Clavulin 125 F Oral Sus Product Monograph

Recent Major Label Changes

Table of Contents

Certain sections or subsections that are not applicable at the time of the preparation of the most recent authorized product monograph are not listed.

Recent Major Label Changes ................................................................................................... 2

Table of Contents ................................................................................................................... 2

Part 1: Healthcare Professional Information ........................................................................... 4

1. 1.

   Indications .................................................................................................................. 4

   1.1. Pediatrics .............................................................................................................. 4

   1.2. Geriatrics .............................................................................................................. 4

2. 2. Contraindications ........................................................................................................ 4
3. 3. Serious Warnings and Precautions Box ....................................................................... 5
4. 4.

   Dosage and Administration ......................................................................................... 5

   4.2. Recommended Dose and Dosage Adjustment ..................................................... 5

   4.3. Reconstitution ...................................................................................................... 8

   4.4. Administration ...................................................................................................... 9

   4.5. Missed Dose ......................................................................................................... 9

5. 5. Overdose..................................................................................................................... 9
6. 6. Dosage Forms, Strengths, Composition, and Packaging ............................................. 10
7. 7.

   Warnings and Precautions ......................................................................................... 11

   General ........................................................................................................................... 11

   Cardiovascular ................................................................................................................ 11

   Hepatic/Biliary/Pancreatic ............................................................................................. 11

   Immune .......................................................................................................................... 12

   Monitoring and Laboratory Tests ................................................................................... 13

   Renal .............................................................................................................................. 13

   Sensitivity/Resistance ..................................................................................................... 13

   Skin ................................................................................................................................. 13

   7.1. Special Populations ............................................................................................. 13

   7.1.1. Pregnancy ....................................................................................................... 13

   7.1.2. Breastfeeding ................................................................................................. 13

   7.1.3. Pediatrics ........................................................................................................ 14

8. 8.

   Adverse Reactions ..................................................................................................... 14

   8.2. Clinical Trial Adverse Reactions .......................................................................... 14

   8.2.1. Clinical Trial Adverse Reactions - Pediatrics .................................................... 14

   8.5. Post-Market Adverse Reactions ......................................................................... 14

9. 9.

   Drug Interactions ...................................................................................................... 15

   9.3. Drug-Behaviour Interactions .............................................................................. 15

   9.4. Drug-Drug Interactions ....................................................................................... 16

   9.5. Drug-Food Interactions ....................................................................................... 16

   9.6. Drug-Herb Interactions ....................................................................................... 16

   9.7. Drug-Laboratory Test Interactions ...................................................................... 16

10. 10.

    Clinical Pharmacology ............................................................................................... 16

    10.1. Mechanism of Action ...................................................................................... 16

    10.3. Pharmacokinetics ........................................................................................... 16

11. 11. Storage, Stability, and Disposal ................................................................................. 18

Part 2: Scientific Information ................................................................................................ 19

1. 13. Pharmaceutical Information ...................................................................................... 19
2. 14. Clinical Trials ............................................................................................................. 19
3. 15. Microbiology ............................................................................................................. 20
4. 16. Non-Clinical Toxicology ............................................................................................. 23

Patient Medication Information ........................................................................................... 29

Part 1: Healthcare Professional Information

1. Indications

CLAVULIN (amoxicillin / clavulanate potassium) is indicated for the treatment of the following infections when caused by CLAVULIN-susceptible strains of the designated bacteria:

• Sinusitis when caused by β-lactamase producing strains of H. influenzae or Moraxella (Branhamella) catarrhalis.
• Otitis Media when caused by β-lactamase producing strains of H. influenzae or Moraxella (Branhamella) catarrhalis.
• Lower Respiratory Tract Infections when caused by β-lactamase producing strains of H. influenzae, K. pneumoniae, S. aureus or Moraxella (Branhamella) catarrhalis.
• Skin and Soft Tissue Infections when caused by β-lactamase producing strains of S. aureus.
• Urinary Tract Infections when caused by β-lactamase producing strains of E. coli.

While CLAVULIN is indicated only for the conditions listed above, infections caused by ampicillin (amoxicillin) susceptible organisms are also amenable to CLAVULIN treatment due to its amoxicillin content. Furthermore, mixed infections caused by organisms susceptible to ampicillin (amoxicillin) and β-lactamase producing organisms susceptible to CLAVULIN should not require the addition of another antibiotic.

To reduce the development of drug-resistant bacteria and maintain the effectiveness of CLAVULIN and other antibacterial drugs, CLAVULIN should be used only to treat infections that are proven or strongly suspected to be caused by susceptible bacteria. When culture and susceptibility information are available, they should be considered in selecting or modifying antibacterial therapy. In the absence of such data, local epidemiology data, susceptibility patterns, and local official antibiotic prescribing guidelines, may contribute to the empiric selection of therapy.

1.1. Pediatrics

Pediatrics (< 18): See 4.2. Recommended Dose and Dosage Adjustment, Pediatrics, 7.1.3. Pediatrics.

1.2. Geriatrics

Geriatrics: See 7. Warnings and Precautions, Hepatic/Biliary/Pancreatic.

2. Contraindications

CLAVULIN is contraindicated in patients:

• with a history of hypersensitivity to the penicillin, or cephalosporin group of β-lactams, or to any ingredients contained in the preparation or component of the container. For a complete listing, see 6. Dosage Forms, Strengths, Composition, and Packaging.
• where infectious mononucleosis is either suspected or confirmed.
• with a previous history of CLAVULIN-associated jaundice/hepatic dysfunction.

3. Serious Warnings and Precautions Box

• Hypersensitivity: Serious and occasionally fatal hypersensitivity (anaphylactic) and severe cutaneous adverse reactions (SCAR) have been reported in patients receiving therapy with beta-lactams, including amoxicillin. See 7. Warnings and Precautions, Hypersensitivity Reactions and 7. Warnings and Precautions, Skin.

4. Dosage and Administration

4.2. Recommended Dose and Dosage Adjustment

Pediatrics (3 months and older)

In infants 12 weeks (3 months) of age or older and in children, b.i.d. use of the CLAVULIN 200 mg and 400 mg formulations is recommended because of a significantly reduced incidence of diarrhea with the b.i.d. regimen (see 8. Adverse Reactions).

Based on the amoxicillin component, CLAVULIN should be dosed as follows in patients aged 12 weeks (3 months) and older:

* The bid regimen is recommended as it is associated with significantly less diarrhea.

**Duration of therapy studied and recommended for acute otitis media is 10 days.

The normal duration of treatment was 7 to 10 days. However, in general, treatment should be continued for a minimum of 48 to 72 hours beyond the time that the patient becomes asymptomatic or evidence of bacterial eradication has been obtained. It is recommended that there be at least 10 days treatment for any infection caused by β-hemolytic streptococci to prevent the occurrence of acute rheumatic fever or glomerulonephritis.

The children's dosage should not exceed that recommended for adults. Children weighing more than 38 kg should be dosed according to adult recommendations.

Table 1 below may be used as a guide to determine the dosage of oral suspension (CLAVULIN -125F or CLAVULIN -250F) according to body weight.

Table 1 – Pediatric Dosage Schedule for CLAVULIN -125F and CLAVULIN -250F Oral Suspensions^a

^a Based on amoxicillin component

^b Dosages are expressed in terms of amoxicillin plus clavulanic acid. These two ingredients are in a ratio of 4:1 in both oral suspensions, CLAVULIN-125F and CLAVULIN-250F.

Twenty (20) mL of reconstituted CLAVULIN -125F oral suspension or ten (10) mL of reconstituted CLAVULIN -250F oral suspension are equivalent to one (1) amoxicillin and clavulanate potassium-500 mg/ 125 mg tablet.

Table 2 below may be used as a guide to determine the dosage of oral suspension (CLAVULIN -200 or CLAVULIN -400) according to body weight.

Table 2 – Pediatric Dosage Schedule for CLAVULIN-200 and CLAVULIN-400 Oral Suspensions

^a Based on amoxicillin component

^b Dosages are expressed in terms of amoxicillin plus clavulanic acid. These two ingredients are in a ratio of 7:1 in both oral suspensions, CLAVULIN-200 and CLAVULIN-400.

A calibrated dropper should be used to measure the appropriate volume for dosing.

Pediatrics (Neonates and children aged <12 weeks (3 months))

Due to incompletely developed renal function affecting elimination of amoxicillin in this age group, the recommended dose of CLAVULIN is 30 mg/kg/day divided q12h, based on the amoxicillin component. Clavulanate elimination is unaltered in this age group. Experience with the 200 mg/5 mL formulation in this age group is limited and, thus, use of the 125 mg/5 mL oral suspension is recommended.

Renal Insufficiency

Dosage adjustment in renal impairment is based on the maximum recommended level of amoxicillin. CLAVULIN presentations with a 7:1 ratio of amoxicillin:clavanulate (i.e. CLAVULIN -200 and -400 oral suspensions) should be used only in patients with a creatinine clearance of more than 30 ml/min.

Pediatrics

4.3. Reconstitution

Reconstitute Powder for Oral Suspension with purified water.

CLAVULIN -125F Powder for Oral Suspension:

The approximate average concentration after reconstitution is 125 mg of amoxicillin (as the trihydrate) and 31.25 mg of clavulanic acid (as the potassium salt) per 5 mL.

Bottle Size

Volume to be added

100 mL

92 mL

CLAVULIN -200 Powder for Oral Suspension:

The approximate average concentration after reconstitution is 200 mg of amoxicillin (as the trihydrate) and 28.5 mg of clavulanic acid (as the potassium salt) per 5 mL.

Bottle Size

Volume to be added

70 mL

64 mL

CLAVULIN -250F Powder for Oral Suspension

The approximate average concentration after reconstitution is 250 mg of amoxicillin (as the trihydrate) and 62.5 mg of clavulanic acid (as the potassium salt) per 5 mL.

Bottle Size

Volume to be added

100 mL

90 mL

CLAVULIN -400 Powder for Oral Suspension

The approximate average concentration after reconstitution is 400 mg of amoxicillin (as the trihydrate) and 57 mg of clavulanic acid (as the potassium salt) per 5 mL.

Bottle Size

Volume to be added

70 mL

62 mL

Shake vigorously.

The reconstituted CLAVULIN -125F and CLAVULIN -250F oral suspension should be stored under refrigeration (2°C to 8°C) and should be used within 10 days. Discard unused suspension after 10 days. The reconstituted CLAVULIN -200 and CLAVULIN -400 oral suspension should be stored under refrigeration (2°C to 8°C) and should be used within 7 days. Discard unused suspension after 7 days (see 11. Storage, Stability, and Disposal).

4.4. Administration

While CLAVULIN can be given without regard to meals, absorption of clavulanic acid when taken with food is greater relative to the fasted state. Dosing in the fasted or fed state has minimal effect on the pharmacokinetics of amoxicillin. The safety and efficacy of CLAVULIN have been established in clinical trials where CLAVULIN was taken without regard to meals.

To minimize potential gastrointestinal intolerance, administer at the start of a meal.

4.5. Missed Dose

If a dose is missed, it should be taken as soon as remembered unless it is almost time for the next dose. The dose should not be doubled to make up for a missed dose.

5. Overdose

Activated charcoal may be administered to aid in the removal of unabsorbed drug. General supportive measures are also recommended.

Many patients have been asymptomatic following overdosage or have experienced primarily gastrointestinal symptoms including stomach and abdominal pain, vomiting, and diarrhea. Rash, hyperactivity, or drowsiness have also been observed in a small number of patients. Amoxicillin crystalluria, in some cases leading to renal failure, has been observed (see 7. Warnings and Precautions).

In the case of overdosage, discontinue CLAVULIN, treat symptomatically, and institute supportive measures as required. If gastrointestinal symptoms and disturbance of the fluid and electrolyte balances are evident, they may be treated symptomatically. CLAVULIN can be removed from the circulation by hemodialysis. A prospective study of 51 pediatric patients at a poison center suggested that overdosages of less than 250 mg/kg of amoxicillin are not associated with significant clinical symptoms and do not require gastric emptying.

Interstitial nephritis resulting in oliguric renal failure has been reported in a small number of patients after overdosage with amoxicillin. Renal impairment appears to be reversible with cessation of drug administration. High blood levels may occur more readily in patients with impaired renal function because of decreased renal clearance of both amoxicillin and clavulanate. Both amoxicillin and clavulanate are removed from the circulation by hemodialysis.

For the most recent information in the management of a suspected drug overdose, contact your regional poison control centre or Health Canada’s toll-free number, 1-844 POISON-X (1-844-764-7669).

1. 6. Dosage Forms, Strengths, Composition, and Packaging

Table 3 – Dosage Forms, Strengths, and Composition

*see section 7. Warnings and Precautions, General

Description

CLAVULIN -125F and 250F are available in bottles of 100 mL.

CLAVULIN -200 and 400 are available in bottles of 70 mL.

7. Warnings and Precautions

Please see 3. Serious Warnings and Precautions Box.

General

The possibility of superinfections with mycotic or bacterial pathogens should be kept in mind during therapy with CLAVULIN. If superinfection should occur (usually involving Enterobacter (Aerobacter), Pseudomonas or Candida), the administration of CLAVULIN should be discontinued and appropriate therapy instituted.

Prolonged use may also occasionally result in overgrowth of non-susceptible organisms.

CLAVULIN, which contains aspartame, should be used with caution in patients with phenylketonuria.

The occurrence of a morbilliform rash following the use of ampicillin in patients with infectious mononucleosis is well documented. This reaction has also been reported following the use of amoxicillin. A similar reaction would also be expected with CLAVULIN.

Clostridium difficile-associated disease

Clostridium difficile -associated disease (CDAD) has been reported with the use of many antibacterial agents, including CLAVULIN. CDAD may range in severity from mild diarrhea to fatal colitis. It is important to consider this diagnosis in patients who present with diarrhea, or symptoms of colitis, pseudomembranous colitis, toxic megacolon, or perforation of colon subsequent to the administration of any antibacterial agent. CDAD has been reported to occur over 2 months after the administration of antibacterial agents.

Treatment with antibacterial agents may alter the normal flora of the colon and may permit overgrowth of Clostridium difficile. Clostridium difficile produces toxins A and B, which contribute to the development of CDAD. CDAD may cause significant morbidity and mortality. CDAD can be refractory to antimicrobial therapy.

If the diagnosis of CDAD is suspected or confirmed, appropriate therapeutic measures should be initiated. Mild cases of CDAD usually respond to discontinuation of antibacterial agents not directed against Clostridium difficile. In moderate to severe cases, consideration should be given to management with fluids and electrolytes, protein supplementation, and treatment with an antibacterial agent clinically effective against Clostridium difficile. Surgical evaluation should be instituted as clinically indicated, as surgical intervention may be required in certain severe cases (see 8. Adverse Reactions).

Cardiovascular

Abnormal prolongation of prothrombin time (increased international normalized ratio (INR)) has been reported in patients receiving CLAVULIN and oral anticoagulants. Appropriate monitoring should be undertaken when anticoagulants are prescribed concurrently. Adjustments in the dose of oral anticoagulants may be necessary to maintain the desired level of anticoagulation.

Kounis syndrome (see 7. Warnings and Precautions, Hypersensitivity Reactions).

Hepatic/Biliary/Pancreatic

Transient hepatitis and cholestatic jaundice have been reported rarely. These events have been noted with other penicillins and cephalosporins. Hepatic injury events associated with CLAVULIN may be severe, and occur predominantly in males and elderly patients and may be associated with prolonged treatment. These events have been very rarely reported in children. Signs and symptoms usually occur during or shortly after treatment, but in some cases may not become apparent until several weeks after treatment has ceased. Hepatic toxicity associated with the use of CLAVULIN is usually reversible. On rare occasions, deaths have been reported (less than 1 death reported per estimated 4 million prescriptions worldwide). These have generally been cases associated with serious underlying diseases or concomitant medications (see 2. Contraindications and 8.5. Post-Market Adverse Reactions, Liver).

CLAVULIN should be used with caution in patients with evidence of hepatic dysfunction.

Immune

Hypersensitivity Reactions

Serious and occasionally fatal hypersensitivity reactions, including:

• angioedema
• anaphylactic/anaphylactoid reactions
• severe cutaneous adverse reactions (SCAR) (e.g., acute generalized exanthematous pustulosis (AGEP), Stevens-Johnson syndrome (SJS), toxic epidermal necrolysis (TEN), and drug reaction with eosinophilia and systemic symptoms (DRESS)). These have been reported in patients on penicillin therapy, including CLAVULIN (amoxicillin / clavulanate potassium).
• Kounis syndrome, a serious allergic reaction that can result in myocardial infarction. Presenting symptoms of such reactions can include chest pain occurring in association with an allergic reaction to amoxicillin-clavulanate.

• Drug-induced enterocolitis syndrome, an allergic reaction with the leading symptom of protracted vomiting (1-4 hours after medicinal product administration), in the absence of allergic skin or respiratory symptoms, has been reported mainly in children receiving amoxicillin-clavulanate. Further symptoms could comprise abdominal pain, lethargy, diarrhea, hypotension or leucocytosis with neutrophilia. In severe cases, drug-induced enterocolitis syndrome can progress to shock.

  (See 8.5. Post-Market Adverse Reactions)

Although these reactions are more frequent following parenteral therapy, they have occurred in patients receiving penicillins orally. These reactions are more apt to occur in individuals with a history of sensitivity to multiple allergens. There have been reports of individuals with a history of cephalosporin hypersensitivity who have experienced severe reactions when treated with penicillins. Before initiating therapy with CLAVULIN, careful inquiry should be made concerning previous hypersensitivity reactions to penicillins, cephalosporins, or other allergens (see 2. Contraindications).

If an allergic reaction occurs, the administration of CLAVULIN should be discontinued and appropriate alternative therapy should be instituted. Serious anaphylactic/anaphylactoid reactions require immediate emergency treatment with epinephrine. Oxygen, intravenous steroids and airway management, including intubation should also be used as indicated.

Haemophagocytic Lymphohistiocytosis/Macrophage Activation Syndrome

Haemophagocytic lymphohistiocytosis (HLH)/macrophage activation syndrome (MAS) has been reported in patients receiving CLAVULIN (see 8.5. Post-Market Adverse Reactions). HLH/MAS is a life-threatening syndrome of pathological immune activation characterized by clinical signs and symptoms of excessive systemic inflammation and is associated with high mortality rates if not recognized early and treated. Clinical signs and symptoms include fever, rash, neurological symptoms, hepatosplenomegaly, lymphadenopathy, cytopenias, high serum ferritin, hypertriglyceridaemia, hypofibrinogenaemia, haemophagocytosis, and abnormalities of liver function and coagulation.

Patients who develop these signs and symptoms should be immediately evaluated and HLH/MAS diagnosis considered. CLAVULIN therapy should be discontinued unless an alternative aetiology for HLH/MAS can be established.

Monitoring and Laboratory Tests

Periodic assessment of renal, hepatic, and hematopoietic function should be made during prolonged therapy with CLAVULIN.

Renal

CLAVULIN is excreted mostly by the kidney. In renal impairment, dosage adjustments should be made based on the maximum recommended level of amoxicillin (see 4.2. Recommended Dose and Dosage Adjustment, Renal Insufficiency).

In patients with reduced urine output, crystalluria has been observed very rarely, predominantly with parenteral therapy. During the administration of high doses of amoxicillin, it is advisable to maintain adequate fluid intake and urinary output in order to reduce the possibility of amoxicillin crystalluria (see 5. Overdose).

Sensitivity/Resistance

Prescribing CLAVULIN in the absence of a proven or strongly suspected bacterial infection is unlikely to provide benefit to the patient and risks the development of drug-resistant bacteria.

Skin

Severe cutaneous adverse reactions (SCAR) have been reported with CLAVULIN (see 7. Warnings and Precautions, Hypersensitivity Reactions).

7.1. Special Populations

7.1.1. Pregnancy

In a single study in women with preterm, premature rupture of the fetal membranes (pPROM), it was reported that prophylactic treatment with CLAVULIN may be associated with an increased risk of necrotising enterocolitis in neonates. Use should be avoided in pregnancy, unless considered essential by the physician.

7.1.2. Breastfeeding

Penicillins (including ampicillin) have been shown to be excreted in human breast milk. It is not known whether clavulanic acid is excreted in breast milk. Caution should be exercised if CLAVULIN is to be administered to a nursing mother.

7.1.3. Pediatrics

Because of incompletely developed renal function in neonates and young infants, the elimination of amoxicillin may be delayed. Dosing of CLAVULIN should be modified in pediatric patients younger than 12 weeks (3 months), see 4.2. Recommended Dose and Dosage Adjustment, Pediatrics (Neonates and children aged <12 weeks (3 months)).

8. Adverse Reactions

8.2. Clinical Trial Adverse Reactions

Clinical trials are conducted under very specific conditions. Therefore, the frequencies of adverse reaction observed in the clinical trials may not reflect frequencies observed in clinical practice and should not be compared to frequencies reported in clinical trials of another drug.

8.2.1. Clinical Trial Adverse Reactions - Pediatrics

A U.S./Canadian clinical trial compared a 10-day CLAVULIN b.i.d. regimen (45/6.4 mg/kg/day q12h) with a 10-day CLAVULIN t.i.d. regimen (40/10 mg/kg/day q8h) in 575 patients with acute otitis media, aged 2 months to 12 years. The incidence of diarrhea was significantly lower in patients who received the b.i.d. regimen compared to patients who received the t.i.d. regimen (9.6% vs. 26.7%; p<0.001). Significantly fewer patients who received the b.i.d. regimen withdrew due to diarrhea compared to patients receiving the t.i.d. regimen (2.8% vs. 7.6%; p=0.009). The incidence of related/possibly related diaper rash was also lower in patients who received the b.i.d. regimen compared to patients who received the t.i.d. regimen (3.1% vs. 6.6%; p =0.054).

8.5. Post-Market Adverse Reactions

The following adverse reactions have been observed during therapy with CLAVULIN.

Black hairy tongue has been reported very rarely. Tooth discolouration has been reported very rarely in children and adults. Good oral hygiene may help to prevent tooth discolouration as it can often be removed by brushing.

Central Nervous System Effects

Aseptic meningitis.

Convulsions may occur with impaired renal function or in those receiving high doses.

Gastrointestinal

Diarrhea has been reported very commonly in adults and commonly in children. Nausea and vomiting have been reported commonly in adults and children. Mucocutaneous candidiasis has been reported commonly. Abdominal cramps, flatulence, constipation, anorexia, colic pain, acid stomach, intestinal candidiasis, antibiotic-associated colitis (including pseudomembranous colitis and haemorrhagic colitis), have been reported rarely. Drug-induced enterocolitis syndrome has been reported (see 7. Warnings and Precautions, Hypersensitivity Reactions). Indigestion has been reported as an uncommon occurrence. If gastrointestinal reactions are evident, they may be reduced by taking CLAVULIN at the start of the meal.

Hemic and Lymphatic Systems

As with other β-lactams, anemia, hemolytic anemia thrombocytopenia, thrombocytopenic purpura, eosinophilia, leukopenia, lymphocytopenia, basophilia, slight increase in platelets, neutropenia and agranulocytosis have been reported rarely during therapy with the penicillins. These reactions are usually reversible on discontinuation of therapy and are believed to be hypersensitivity phenomena. Prolongation of bleeding time and prolongation of prothrombin time have also been reported.

Immune

Note: If any hypersensitivity dermatitis reaction occurs, treatment with CLAVULIN should be discontinued (see 7. Warnings and Precautions, Hypersensitivity Reactions).

General hypersensitivity reactions: Erythematous maculopapular rash, urticaria, anaphylaxis (see 7. Warnings and Precautions, Hypersensitivity Reactions), hypersensitivity vasculitis and pruritus.

Other immune system disorders: A morbilliform rash in patients with mononucleosis. Interstitial nephritis can occur rarely, Kounis syndrome (7. Warnings and Precautions, Hypersensitivity Reactions), Serum sickness-like syndrome.

Haemophagocytic lymphohistiocytosis/macrophage activation syndrome (7. Warnings and Precautions, Haemophagocytic Lymphohistiocytosis/Macrophage Activation Syndrome).

Skin and subcutaneous tissue disorders

Severe cutaneous adverse reactions (SCAR): Rarely erythema multiforme and Stevens-Johnson syndrome (SJS) have been reported. Other reactions including angioedema, toxic epidermal necrolysis (TEN), bullous exfoliative dermatitis, and acute generalised exanthematous pustulosis (AGEP) as in the case of other β-lactam antibiotics, have been seen rarely. Drug reaction with eosinophilia and systemic symptoms (DRESS) has also been reported.

Symmetrical drug-related intertriginous and flexural exanthema (SDRIFE) has been reported.

Linear IgA disease has also been reported.

Liver

Transient hepatitis and cholestatic jaundice have been reported rarely. These events have been noted with other penicillins and cephalosporins. Moderate rises in AST (SGOT), alkaline phosphatase, lactic dehydrogenase, and/or ALT (SGPT) have been noted in patients treated with ampicillin class antibiotics. The significance of these findings is unknown.

Other

Vaginitis, headache, bad taste, dizziness, malaise, glossitis, and stomatitis.

Renal and Urinary Tract Disorders

Very rare: crystalluria and interstitial nephritis (see 5. Overdose).

9. Drug Interactions

9.3. Drug-Behaviour Interactions

The interaction of CLAVULIN with individual behavioural risks (e.g. cigarette smoking, cannabis use, and/or alcohol consumption) has not been studied.

9.4. Drug-Drug Interactions

In common with other broad spectrum antibiotics, amoxicillin-clavulanate may reduce the efficacy of combined oral contraceptives by altering the gut-flora to result in lower estrogen reabsorption. Concomitant use of probenecid is not recommended, and may result in increased and prolonged blood levels of amoxicillin, but not of clavulanic acid.

Increases in prothrombin time, INR or bleeding have been reported in patients maintained on coumarin anticoagulants, such as acenocoumarol and warfarin and then coadministered amoxicillin or CLAVULIN. If coadministration is necessary, the prothrombin time or INR should be carefully monitored upon antibiotic addition or withdrawal.

Reduction in the median pre-dose concentration of the mycophenolic acid (MPA), the active metabolite of mycophenolate mofetil, of approximately 54% has been reported in renal transplant recipients in the days immediately following the commencement of oral amoxicillin-clavulanic acid.

These reductions in pre-dose MPA concentrations from baseline (mycophenolate mofetil alone) tended to diminish with continued antibiotic use and cease after discontinuation. The change in pre-dose level may not accurately represent changes in overall MPA exposure; therefore, clinical relevance of these observations is unclear.

Penicillins may reduce the excretion of methotrexate causing a potential increase in toxicity.

9.5. Drug-Food Interactions

This drug may be taken with or without food, however absorption of clavulanic acid when taken with food is greater relative to the fasted state (see 4.4. Administration).

9.6. Drug-Herb Interactions

Interactions with herbal products have not been established.

9.7. Drug-Laboratory Test Interactions

CLAVULIN may:

• cause false-positive reactions when testing for the presence of glucose in urine.
• distort assay results for estriol in pregnant women.

10. Clinical Pharmacology

10.1. Mechanism of Action

Amoxicillin exerts a bactericidal action against sensitive organisms during the stage of active multiplication through the inhibition of the biosynthesis of bacterial cell wall mucopeptides. Clavulanic acid inhibits specific β-lactamases of some microorganisms and allows amoxicillin to inhibit amoxicillin (ampicillin) resistant organisms which produce clavulanic acid sensitive β-lactamases.

10.3. Pharmacokinetics

There is no significant difference between the absorptions of amoxicillin and clavulanic acid, whether administered separately or as a combination in CLAVULIN.

The half-life of amoxicillin in adults when given alone is 1.2 hours and 1.3 hours when given in the form of amoxicillin and clavulanate potassium. The half-life of clavulanic acid alone is 1.0 hour. Time above the minimum inhibitory concentration of 1.0 mcg/mL for amoxicillin has been shown to be similar after corresponding b.i.d. and t.i.d. dosing regimens of amoxicillin and clavulanate potassium in adults and children.

Concurrent administration of probenecid delays amoxicillin excretion but does not delay renal excretion of clavulanic acid.

Neither component of CLAVULIN is highly protein-bound; clavulanic acid has been found to be approximately 30% bound to human serum protein and amoxicillin approximately 20% bound.

Special populations and conditions

Pediatrics

The plasma concentrations of amoxicillin and clavulanic acid following single doses of an oral suspension containing amoxicillin and clavulanic acid in a ratio of 4:1 are given in Table 4 below.

Table 4 – Mean Plasma Concentrations of Amoxicillin and Clavulanic Acid

* A single dose of 6.6 mg/kg of amoxicillin plus 1.7 mg/kg of clavulanic acid is equivalent to one third of the daily dose of 25 mg/kg of CLAVULIN oral suspension (4:1 ratio). A single dose of 13.3 mg/kg of amoxicillin plus 3.3 mg/kg of clavulanic acid is equivalent to one third of the daily dose of 50 mg/kg of CLAVULIN oral suspension (4:1 ratio).

Some pharmacokinetic parameters for these children are given in Table 5 below.

Table 5 – Summary of amoxicillin and clavulanic acid pharmacokinetic parameters in children

The steady state pharmacokinetic profiles of amoxicillin and clavulanic acid were compared after dosing CLAVULIN oral suspension at a dose of 45/6.4 mg/kg/day (7:1 ratio) q12h and 40/10 mg/kg/day (4:1 ratio) q8h in pediatric patients with age ranges from 1 month to 12 years. The elimination kinetics of amoxicillin and clavulanic acid in b.i.d. or t.i.d. regimens to pediatric patients aged 4 months or greater were similar to those of adults. However, in infants younger than 4 months, half-lives were delayed due to the relative immaturity of renal function in these infants.

1. 11. Storage, Stability, and Disposal

Store powder in a dry place at room temperature (15°C – 25°C). Use the powder only if its appearance is white to off-white.

The reconstituted CLAVULIN -125F and CLAVULIN -250F oral suspension should be stored under refrigeration (2°C to 8°C) and should be used within 10 days. Discard unused suspension after 10 days.

The reconstituted CLAVULIN -200 and CLAVULIN -400 oral suspension should be stored under refrigeration (2°C to 8°C) and should be used within 7 days. Discard unused suspension after 7 days.

Keep bottle tightly closed at all times.

Keep out of reach and sight of children.

Part 2: Scientific Information

13. Pharmaceutical Information

Drug Substance

Non-proprietary name of the drug substance(s): amoxicillin / clavulanate potassium

Amoxicillin:

Chemical name: Trihydrate of 6-[(-)-α-amino-4-hydroxy-phenylacetamido]-penicillanic acid]

Molecular formula and molecular mass: C₁₆H₁₉N₃O₅S.3H₂O / 419.47 (trihydrate) and 365.41 (anhydrous)

Structural formula:

Physicochemical properties: Amoxicillin trihydrate is a white or slightly off-white highly hygroscopic powder.

Clavulanate Potassium:

Chemical name: Potassium (Z)-(2R,5R)-3-(2-hydroxyethylidene)-7- oxo-4-oxa-1-azabicyclo[3,2,0]-heptane-2-carboxylate

Molecular formula and molecular mass: C₈H₈NO₅K / 199.16 (free acid) and 237.25 (potassium salt)

Structural formula:

Physicochemical properties: A white to pale yellow powder.

14. Clinical Trials

Clinical Trial information was not included in Product Monograph at the time of initial authorization.

15. Microbiology

In the list below, organisms are categorised according to their in vitro susceptibility to amoxicillin-clavulanate based mainly on studies published during 2001-2011.

Table 6 – In vitro susceptibility of micro-organisms to amoxicillin-clavulanate

Where clinical efficacy of amoxicillin-clavulanate has been demonstrated in clinical trials this is indicated with an asterisk (*).

Organisms that do not produce beta-lactamase are identified (with ^†). If an isolate is susceptible to amoxicillin, it can be considered susceptible to amoxicillin-clavulanate.

Commonly susceptible species

Gram-positive aerobes:

Enterococcus faecalis

Streptococcus bovis

Streptococcus pyogenes^†

Streptococcus agalactiae^†

Streptococcus spp. (other β-hemolytic) ^†

Staphylococcus aureus (methicillin susceptible)*

Staphylococcus saprophyticus (methicillin susceptible)

Coagulase negative staphylococcus (methicillin susceptible)

Gram-negative aerobes:

Haemophilus influenzae*

Haemophilus parainfluenzae

Moraxella catarrhalis*

Pasteurella multocida

Proteus mirabilis

Gram positive anaerobes:

Clostridium spp.

Peptostreptococcus spp.

Gram-negative anaerobes:

Eikenella corrodens

Fusobacterium spp.

Porphyromonas spp.

Prevotella spp.

Species for which acquired resistance may be a problem

Gram-positive aerobes:

Streptococcus pneumoniae^†

Viridans group streptococcus

Gram-negative aerobes:

Escherichia coli*

Klebsiella oxytoca

Klebsiella pneumoniae*

Klebsiella spp.

Proteus vulgaris

Salmonella spp.

Shigella spp.

Gram-negative anaerobes:

Bacteroides fragilis

Bacteroides spp.

Bacteroides thetiotamicron

Inherently resistant organisms

Gram-positive aerobes:

Enterococcus faecium

Gram-negative aerobes:

Acinetobacter spp.

Aeromonas spp.

Citrobacter spp.

Enterobacter spp.

Hafnia alvei

Morganella morganii

Providencia rettgeri

Providencia stuartii

Pseudomonas spp.

Serratia marcescens

Susceptibility Testing

Interpretive Criteria for Dilution and Disk Diffusion Testing

MIC and disk diffusion results should be interpreted according to Table 7 and are based on CLSI methodologies (CLSI M7-A9 and M2-A10). The recommended dilution pattern utilizes a constant amoxicillin/clavulanate potassium ratio of 2 to 1 in all tubes with varying amounts of amoxicillin. MICs are expressed in terms of the amoxicillin concentration in the presence of clavulanic acid at a constant 2 parts amoxicillin to 1 part clavulanic acid. The disk procedure uses paper disks impregnated with 30 mcg amoxicillin/clavulanate potassium (20 mcg amoxicillin plus 10 mcg clavulanate potassium).

A report of S (“Susceptible”) indicates that the antimicrobial is likely to inhibit growth of the pathogen if the antimicrobial compound in the blood reaches the concentration usually achievable. A report of I (“Intermediate”) indicates that the result should be considered equivocal, and, if the microorganism is not fully susceptible to alternative, clinically feasible antimicrobials, the test should be repeated. This category implies possible clinical applicability in body sites where the drug is physiologically concentrated or in situations where high doses of antimicrobial can be used. This category also provides a buffer zone that prevents small uncontrolled technical factors from causing major discrepancies in interpretation. A report of R (“Resistant”) indicates that the antimicrobial is not likely to inhibit growth of the pathogen if the antimicrobial compound in the blood reaches the concentration usually achievable; other therapy should be selected.

Table 7 – Susceptibility Test Result Interpretive Criteria for Amoxicillin/Clavulanate Potassium

Note 1: β-lactamase–negative, ampicillin-resistant H. influenzae isolates must be considered resistant to amoxicillin/clavulanate potassium

Note 2: Staphylococci which are susceptible to amoxicillin/clavulanate potassium but resistant to methicillin or oxacillin must be considered as resistant

Note 3: Susceptibility of S. pneumoniae should be determined using a 1-mcg oxacillin disk. Isolates with oxacillin zone sizes of ≥ 20 mm are susceptible to amoxicillin/clavulanate potassium. An amoxicillin/clavulanate potassium MIC should be determined on isolates of S. pneumoniae with oxacillin zone sizes of ≤ 19 mm.

Quality Control Reference Ranges

Standardized susceptibility test procedures require the use of quality control microorganisms to determine the performance of the test procedures. The expected quality control results based on CLSI MIC and disk diffusion methods are shown in Table 8 (CLSI M100-S21).

Table 8 – Acceptable Quality Control Ranges for Amoxicillin/Clavulanate Potassium

ATCC is a trademark of the American Type Culture Collection.

Note 1: When using Haemophilus Test Medium (HTM)

16. Non-Clinical Toxicology

General toxicology

Single Dose

The acute toxicity of amoxicillin trihydrate and potassium clavulanate, formulated in a 2:1 and 4:1 ratio, was determined in mice and rats dosed orally and intravenously. LD_50's are shown in Table 9.

Table 9 – Acute Toxicity

* estimated

** calculated in terms of amoxicillin and clavulanic acid.

All animals were observed for 14 days. Soft faeces which were observed in rats at the beginning of the observation period regained good general condition by the end of the observation period. All mice showed a slight dose-related loss of condition for up to 72 hours after dosing, thereafter remaining in good condition for the duration of the study. Animals, dosed by the intravenous route, which survived were observed to have mild convulsions and abnormal gait 2-3 minutes after dosing. Those, which did not survive, convulsed immediately on dosing and died within 1 minute.

The LD₅₀ of clavulanate potassium administered orally to 4 day old rats was determined to be 1,360 mg/kg. This compares with an oral LD₅₀ of greater than 10,000 mg/kg for adult rats. In these neonates, weight loss, diarrhea and abdominal distension were frequently observed following dosing.

Repeat Dose

Rats

Amoxicillin trihydrate and clavulanate potassium formulated in a 2:1 ratio were administered orally by gavage to 3 groups of rats each comprising 10 males and 10 females at doses of 20/10, 60/30 or 180/90 mg/kg/day for 4 weeks. A fourth group served as a control. Clinical condition and laboratory determinations were monitored and post-mortem and histopathologic determinations were carried out. There were no deaths during the study. Apart from the passage of slightly soft faeces in all treated groups, there were no adverse clinical signs. Body weight gain and food intake were comparable with controls. Water intake was increased in the male high dose group (8%, 16.3%, 16.8% and 12.2% for weeks 1, 2, 3 and 4, respectively). Female rats showed an overall increase in water consumption of 22%, 11% and 13% for low, intermediate and high dose groups, respectively. Hematology and blood chemistry parameters were comparable to controls and within accepted normal limits. There was a statistically significant increase in urine output in the low and high dose male groups compared to controls. Macroscopic examination revealed an increased incidence of caecal enlargement in all treated groups and was marginally greatest at the high dose level. There was a statistically significant decrease in relative liver weights in both sexes (-9%, -14% and -9% for high, intermediate and low dose male groups, respectively and -12%, -16% and -6% for equivalent female groups). The mean relative thymus weight in the high dose male group was also significantly decreased by 21% and the relative heart weight in the intermediate dose female group was significantly reduced by 12% compared with control. Histological examination of the kidneys revealed minimal chronic inflammatory cell infiltration in a proportion of animals from all groups and was associated with occasional distended tubules and tubules characterized by basophilic staining of the cells of the epithelium.

Amoxicillin trihydrate and clavulanate potassium formulated in a 2:1 ratio were administered orally by gavage to four groups of Sprague-Dawley rats, each comprising 15 males and 15 females, at doses of 20/10, 40/20, 100/50 or 800/400 mg/kg/day for 26 weeks. A fifth group served as a control. Five male and 5 female rats were added to each of the high dose and control groups to determine the effect of drug withdrawal. At the end of the treatment period, these two groups were left undosed for a period of four weeks before sacrificing. Clinical condition and laboratory determinations were monitored and post-mortem and histopathologic determinations were carried out.

There were 4 deaths during the treatment period: one male and two females in the 20/10 mg/kg/day group and one female in the 40/20 mg/kg/day group. There were no deaths during the withdrawal period. Salivation immediately after dosing was noted in both male and female high dose groups. For males receiving 800/400 mg/kg/day, 21% lower body weight gains were recorded from week 3 onwards and 10% lower body weight gains were recorded in the 100/50 mg/kg/day group. Females receiving 800/400 mg/kg/day had lower body weight gains of 62% recorded from week 13.

Decreased urine volumes (males - 30%, females - 54%) were recorded in the 800/400 mg/kg/day group. A statistically significant increase in osmolality was noted in the female high dose group compared to controls.

There was an increase in total white blood cell count associated with an increase in lymphocytes in male rats from the high dose group. This group also had shorter APTT (Activated Partial Thromboplastin Time) while a non-dose related shortened PT (Prothrombin Time) was observed for males receiving 800/400, 100/50, or 40/20 mg/kg at various intervals during treatment, and for all treated males after 24 weeks. At the end of the withdrawal period, values for all parameters were similar to controls. Blood chemistry investigations revealed lower serum albumin (5 to 16%) and higher globulin levels (16 to 30%) during weeks 12 and 24 for male animals receiving 800/400 mg/kg, with an associated decrease in A/G ratios.

A similar effect was seen at week 24 for males receiving 100/50 mg/kg. High dose female rats had globulin levels and A/G ratios similar to controls. However, total protein levels were lower than controls, with an associated decrease in serum albumin levels. At the end of the withdrawal period the only difference from controls was a reduction in total serum protein in females.

At post-mortem examination, a prominent limiting ridge was seen in the stomachs of nearly all the high dose group rats and 1 male dosed at 100/50 mg/kg. Distension of the caecum was seen at all dose levels in a dose-related fashion. At the end of the withdrawal period these findings were no longer observed. Significantly increased liver weights (males - 40%; females - 22%), spleen weights (females - 23%) and kidney weights (males - 10%) were recorded for the high dose group. There was an increase of 30% in liver weights in high dose females and an increase of 26% in kidney weights of high dose males at the end of the withdrawal period. Treatment related microscopic effects were seen in high dose rats of both sexes.

These were hepatocyte enlargement in centrilobular and mid-zonal areas of the liver, hyperplasia of the non-glandular epithelium of the stomach in the region of the limiting ridge and distension of the lumen of the caecum. The only persistent change present after the withdrawal period was hepatocyte enlargement in all previously dosed males.

A study of similar design was carried out in which identical doses of only the clavulanic acid component of the combination described above were administered. In general, the results were similar to those reported above for the combination.

Dogs

Amoxicillin trihydrate and clavulanate potassium formulated in a 2:1 ratio were administered orally by gavage to 3 groups of beagle dogs, each comprising 2 males and 2 females, at doses of 20/10, 60/30 or 180/90 mg/kg/day for 28 days. A fourth group served as a control. Clinical condition and laboratory determinations were monitored and post-mortem and histopathologic determinations were carried out. There were no deaths during the study. The high dose animals showed immediate signs of excessive salivation and severe vomiting was seen up to 2-1/2 hours after dosing. Vomiting was present but less severe in the female intermediate dose group. Body weight gain, food and water consumption and hematology were unaffected by treatment. The blood glucose level of the 60/30 mg/kg dosed male dogs was raised 25% on day 13 and 11% on day 27. These two dogs also showed increases in mean BUN (70%), total protein (5%) and albumin (10%) concentrations at the terminal bleed. The high dose group had reduced total protein (11%) and albumin (10%) levels on day 27. Female dogs dosed at 180/90 mg/kg had total protein levels reduced by 4% and total albumin levels reduced by 12% and 10% at interim and terminal bleeds.

All dose groups had SGOT activity slightly reduced on days 13 and 27. A pronounced enzymuria and minor proteinuria was seen in one male dog of the low dose group. All dosed groups had slight elevation in osmolality and electrolyte excretion. The low dose female group had a slight elevation in urinary alkaline phosphatase (UAP) activity while the urine concentration capacity of test animals was marginally raised. Macroscopic post-mortem examinations did not reveal any treatment-related changes. Histological examination revealed that in the colon of two female dogs in the high dose group, distended glands were prominent and were associated with chronic inflammatory changes both in the colon and in the mucosa of the duodenum in one instance. No other changes were observed that would be considered to be related to the administration of the test compound.

Amoxicillin trihydrate and clavulanate potassium formulated in a 2:1 ratio were administered orally by gavage to four groups of Beagle dogs, each comprising 4 females and 4 males, at doses of 10/5, 20/10, 40/20 or 100/50 mg/kg/day for 26 weeks. A fifth group served as a control. Three male and 3 female dogs were added to each of the high dose and control groups to determine the effect of drug withdrawal. At the end of the treatment period, these two groups were left undosed for a period of 30 days before sacrificing. Clinical condition and laboratory determinations were monitored and post-mortem and histopathologic determinations were carried out.

There were no deaths during the study. Salivation and emesis including the occasional presence of blood streaks (1 mL) in the vomitus were observed in the high dose groups. A low incidence of fecal occult blood was observed in both treated and control animals but the highest incidence occurred in the high dose group after 3 months of treatment. Abnormal granulations in segmented neutrophils were observed most frequently in animals from the high dose group.

Serum glucose levels in males from all treated groups and females from the low and high dose groups were found to be 8 - 29% greater than in controls on some of the assessment occasions during treatment. Similarly, high dose males and females had decreased total protein levels of 9 - 13% on various occasions during treatment. In both cases the absolute magnitude of the change was small with the observed values not falling outside of normal ranges for Beagle dogs. Focal reddening and petechiation of the mucosa of the pyloric antrum, the presence of white patchy areas in the liver and the presence of white streaks along the cortico-medullary junctions of the kidneys were recorded more frequently for animals of the treated groups than for control animals. At the end of the recovery period kidney changes and some GI effects remained. Histopathological studies revealed hepatic and renal changes in the form of cytoplasmic glycogen diminution or disappearance and tubular vacuolization. The kidney and liver changes identified in dogs killed after 6 months of treatment were not observed in dogs of the regression group. Histopathological examination of the GI tract revealed capillary congestion and some extravasation of erythrocytes in the superficial mucosa of the fundus and pylorus in both treated and control dogs.

A study of similar design was carried out in which identical doses of only the clavulanic acid component of the combination described above were administered. In general, the results were similar to those reported above for the combination.

Reproductive and developmental toxicology

Fertility and General Reproductive Performance

Amoxicillin trihydrate and clavulanate potassium in a 2:1 ratio were administered orally by gavage to 3 groups of rats, each comprising 24 males and 24 females, at doses of 20/10, 100/50 or 800/400 mg/kg/day. A fourth group served as a control. Male rats were dosed daily for a minimum of 63 days prior to mating and continuing until weaning of offspring on day 21. Female rats were treated for 15 days prior to mating until weaning or until selected for caesarean section at the end of gestation. On gestation day 20, 10 females/group were sacrificed, a caesarean section was carried out and the remaining 14 females/group were allowed to litter normally. Two high dose males died, one each during study week 11 and 15. Necropsy indicated impaction of the caecal content for one while the other showed pulmonary hemorrhage. Treatment related effects in the high dose males included a slight increase in wheezing and hair loss, decrease in mean body weight gain (21%) and a moderate increase in soft stools.

A slight increase in hair loss was noted in the 100/50 and 800/400 mg/kg/day females. Fertility and general reproductive performance was not affected by treatment as assessed by pregnancy rate and duration of gestation. Male and female mean pup body weights were statistically significantly higher in the 100/50 mg/kg/day group when compared to control. Although not statistically significant, a decrease, which tended to be dose related, was observed with respect to viable fetuses, total implantations and corpora lutea per dam. Two F₁ fetuses, from the 800/400 mg/kg dose group, had malformations (one had a malformed scapula and the other a thread-like tail and small anus). Litter size, foetal loss and development and behaviour of pups were not adversely affected by treatment.

A study of similar design was carried out in which identical doses of only the clavulanic acid component of the combination described above were administered. The results were generally similar to those reported above for the combination with the addition that 2 fetuses from the 400 mg/kg/day dose group exhibited scoliosis.

Teratology

Three groups of 30 female rats were mated and amoxicillin trihydrate and clavulanate potassium in a 2:1 ratio were then administered from day 6 to day 15 of gestation at doses of 20/10, 100/50 or 800/400 mg/kg/day. A fourth group served as a control. On day 20 of gestation, 20 females/group were sacrificed and a caesarean section was carried out while the remaining 10/group were allowed to litter normally. One dam in the 100/50 mg/kg/day group died; however, the dam was normal internally. Maternal observations revealed a dose related loss of hair, a reduction (11 to 23%) in mean maternal body weight gain for gestation days 6 to 20 and a decrease in food consumption. Slight increases in post-implantation losses were seen in the treated groups, but these were neither dose-related nor statistically significant. Pregnancy rate, litter size, foetal loss and mean pup weights were not affected by the treatment.

The incidence of bent ribs was dose-related and scoliosis was observed in three offspring of dams dosed at 100/50 and 800/400 mg/kg/day. Other offspring abnormalities included extra sternebrae (1 pup), numerous petechiae on the stomach and misplace sternebrae (1 pup) and cleft lip with several skeletal anomalies involving the vertebrae, ribs, skull and sternum (1 pup).

A study of similar design was carried out in which identical doses of only the clavulanic acid component of the combination described above were administered. The results were generally similar to those reported above for the combination with the addition that a dose related reduction in ossification and a statistically significant decrease in mean pup body weight were also observed.

Perinatal and Postnatal Studies

Amoxicillin trihydrate and clavulanate potassium in a ratio of 2:1 were administered orally by gavage to 3 groups, each comprising 20 pregnant rats, at doses of 20/10, 100/50 or 800/400 mg/kg/day from day 15 of gestation, through lactation to 21 days post-partum. A fourth group served as a control. Among parent animals, no deaths were observed but there was a slight decrease (17%) of mean body weight in the 800/400 mg/kg/day group on gestation days 15 to 20 and lactation days 0 to 4. Among the litters, 6 deaths were observed; 5 in the 100/50 mg/kg/day group and 1 in the 800/400 mg/kg/day group. A statistically significant decrease in mean number of viable pups per litter in the high dose group was observed. There was a statistically significant decrease in pup survival in the 100/50 mg/kg/day dose group on lactation days 4, 8, 12 and 21 and a small statistically insignificant decrease in the 800/400 mg/kg/day group. In the F1 generation animals, which were mated, a statistically significant decrease in total implantations per dam and corpora lutea was observed for animals in dams of the 800/400 mg/kg/day group compared to control. The F1 generation parameters revealed no other biologically meaningful differences or dose-related trends in litter observations, behavioural and developmental indices, neuropharmacological responses or reproductive capability of any treatment group when compared with control.

A study of similar design was carried out in which identical doses of only the clavulanic acid component of the combination described above were administered. The maternal effects observed were, in general, similar to those reported above for the combination preparation. In the F1 generation, 1 pup from each of the 50 and 400 mg/kg dosage groups had bilateral rudimentary ribs and 1 pup from the 400 mg/kg dosage group had hydrocephaly in addition to bilateral rudimentary ribs.