Robaxisal C 1/2: Uses, Side Effects and Dosage

SERIOUS WARNINGS AND PRECAUTIONS

What is Robaxisal C ½ used for?

Robaxisal C ½ is indicated for moderate pain due to or associated with skeletal muscle spasm: acute torticollis, acute strains and sprains, acute low back pain, acute tenosynovitis, ankle sprain, fracture, trauma, acute bursitis, acute myositis, whiplash injury.

How does Robaxisal C ½ work?

Robaxisal C ½ consists of codeine, acetylsalicylic acid (ASA), and methocarbamol.

Codeine is a painkiller belonging to the class of drugs known as opioids. It relieves pain by acting on specific nerve cells of the spinal cord and brain. ASA reduces pain, fever and inflammation. Methocarbamol is a muscle relaxant.

What are the ingredients in Robaxisal C ½?

Medicinal ingredients: methocarbamol, acetylsalicylic acid (ASA) and codeine phosphate

Non-medicinal ingredients: Cellulose, cornstarch, FD&C Blue No. 1, FD&C Red No. 40, FD&C Yellow No. 6, magnesium stearate, polyethylene glycol, povidone, sodium starch glycolate and stearic acid.

Robaxisal C ½ comes in the following dosage forms:

Tablet, each of which contains methocarbamol 400 mg, ASA 325 mg and codeine phosphate 32.4 mg

Do not use Robaxisal C ½ if:

• your doctor did not prescribe it for you
• you are allergic to methocarbamol, ASA, codeine phosphate or any of the other ingredients in Robaxisal C ½
• you can control your pain by the occasional use of other pain medications. This includes those available without a prescription
• you have severe asthma, trouble breathing, or other breathing problems
• you have any heart problems
• you have bowel blockage or narrowing of the stomach or intestines
• you have severe pain in your abdomen
• you have a head injury
• you are at risk for seizures

• you suffer from alcoholism

• you are taking or have taken within the past 2 weeks a Monoamine Oxidase inhibitor (MAOi) (such as phenelzine sulphate, tranylcypromine sulphate, moclobemide or selegiline)
• you are going to have, or recently had, a planned surgery
• you are less than 18 years old and are having (or have recently had) your tonsils or adenoids removed because of frequent interruption of breathing during sleep
• have a blood clotting disorder (such as hemophilia, von Willebrand’s disease, thrombocytopenia, or severe vitamin K deficiency)
• you have had an allergic reaction (such as problems breathing, itchiness, rash, swelling) to ASA or other nonsteroidal anti-inflammatory drugs (NSAIDs) or to tartrazine dye.
• you have stomach ulcers or other serious stomach or bowel sores.
• you have been told by your doctor that you break down codeine rapidly. This can lead to codeine overdose even at the usual adult dose.
• you are pregnant or planning to become pregnant or you are in labour
• you are breastfeeding. The use of codeine-containing products while breast-feeding may harm your baby. If you breastfeed and take Robaxisal C ½, seek immediate medical care for your baby if they are overly drowsy, sedated, have difficulty breast-feeding, have breathing difficulties, and are floppy (have decreased muscle tone). This is very serious for the baby and can lead to death. Tell the baby’s doctor that you are breastfeeding and took Robaxisal C ½.

• Children, teenagers, and young adults with varicella or influenza, unless directed by a physician.

To help avoid side effects and ensure proper use, talk to your healthcare professional before you take Robaxisal C ½. Talk about any health conditions or problems you may have, including if you:

• have a history of illicit or prescription drug or alcohol abuse
• have severe kidney, liver or lung disease
• have low blood pressure
• have past or current depression
• suffer from chronic or severe constipation
• are taking tranquilizers, sedatives, sedating antihistamines, other depressants, other salicylates, or 3 or more alcoholic beverages per day
• have a history of sleep apnea
• have asthma associated nasal polyps, as this means an increased risk of sensitivity to ASA
• have a history of bleeding or are taking blood thinners
• suffer from migraines
• are pregnant, planning on becoming or become pregnant while taking Robaxisal C ½.

Other warnings you should know about:

Robaxisal C ½ is not recommended for anyone who has or is at risk for breathing problems such as:

• lung infections, or respiratory conditions
• neuromuscular disorders
• severe heart problems
• recent multiple traumas or extensive surgical procedures

Some people metabolize codeine at a much faster rate than the general population, which may lead to accidental overdose, if this should happen to you, seek help immediately (see Overdose, for symptoms of overdose and what to do if it happens). If you know that you metabolize codeine rapidly, tell your doctor BEFORE starting this medication.

Opioid dependence and addiction: There are important differences between physical dependence and addiction. It is important that you talk to your doctor if you have questions or concerns about abuse, addiction, or physical dependence.

Reye's syndrome: ASA may increase the risk of Reye's syndrome, a rare but often fatal condition. Caution should be used in administering ASA-containing medications to young adults who have fever, flu, or chicken pox. Robaxisal C ½ should not be administered to children.

Do not take this medicine for 5 to 7 days before any surgery, including dental surgery, unless otherwise directed by your physician or dentist.

Medical tests: Before you have any medical tests done, tell the person in charge that you are taking Robaxisal C ½. ASA and codeine may interfere with the results of certain tests done in blood and urine.

Testing and check-ups: Your healthcare professional will regularly monitor your health. This includes monitoring for signs of:

• misuse and abuse.
• sleep apnea (a sleep disorder which causes pauses in breathing or shallow breathing while sleeping).
• respiratory depression and sedation (e.g., slow, shallow, or weak breathing).

Pregnancy, nursing, labour and delivery: Do not use Robaxisal C ½ while pregnant, nursing, during labour or delivery. Opioids can be transferred to your baby through breast milk, or while still in the womb. Robaxisal C ½ can then cause life-threatening breathing problems in your unborn baby or nursing infant.

Driving and using machines: Before you do tasks, which may require special attention, you should wait until you know how you react to Robaxisal C ½. Robaxisal C ½ can cause:

• drowsiness
• dizziness or
• lightheadedness

This can usually occur after you take your first dose and when your dose is increased.

Disorder of the adrenal gland: You may develop a disorder of the adrenal gland called adrenal insufficiency. This means that your adrenal gland is not making enough of certain hormones. You may experience symptoms such as:

• nausea, vomiting
• feeling tired, weak, or dizzy
• decreased appetite

You may be more likely to have problems with your adrenal gland if you have been taking opioids for longer than one month. Your doctor may do tests, give you another medication, and slowly take you off Robaxisal C ½.

Serotonin toxicity (also known as serotonin syndrome): Codeine, one of the ingredients of Robaxisal C ½ can cause serotonin toxicity (also known as serotonin syndrome), a rare but potentially life-threatening condition. It can cause serious changes in how your brain, muscles and digestive system work. You may develop serotonin toxicity (also known as serotonin syndrome) if you take Robaxisal C ½ with certain antidepressants or migraine medications.

Serotonin toxicity (also known as serotonin syndrome) symptoms include:

• involuntary eye movements
• fever (>38°C), heavy sweating, flushing, shivering, diarrhea, nausea, vomiting.
• muscle shakes, jerks, twitches or stiffness, overactive reflexes, loss of coordination.
• fast heartbeat, changes in blood pressure.
• confusion, agitation, restlessness, hallucinations, mood changes, unconsciousness and coma.

Sexual Function/Reproduction: Long term use of opioids may lead to a decrease in sex hormone levels. It may also lead to low libido (desire to have sex), erectile dysfunction or being infertile.

Sleep apnea: Opioids can cause a problem called sleep apnea (stopping breathing from time to time while sleeping). Tell your doctor if you have a history of sleep apnea or if anyone notices that you stop breathing from time to time while sleeping.

Serious Skin Reactions: In rare cases, serious or life-threatening skin reactions listed below have been reported with some NSAIDs, such as Robaxisal C ½.

• Drug reaction with eosinophilia and systemic symptoms (DRESS)
• Stevens-Johnson syndrome (SJS),
• toxic epidermal necrolysis (TEN),
• exfoliative dermatitis and
• erythema multiforme

You may be at a greater risk of experiencing a serious skin reaction usually during the first month of treatment. See the Serious side effects and what to do about them table, below, for more information on these and other serious side effects.

Worsened Pain: Taking opioids for pain can sometimes have the unintended effect of making your pain feel worse (opioid-induced hyperalgesia), even though your opioid dose has been unchanged or increased. This can also include feeling pain in new places in your body, or feeling pain from something that would not normally hurt, for example, feeling pain from clothing touching your skin. Tell your doctor if you notice a change like this in your pain while you are taking Robaxisal C ½.

Tell your healthcare professional about all the medicines you take, including any drugs, vitamins, minerals, natural supplements, or alternative medicines.

The following may interact with Robaxisal C ½:

• Alcohol. This includes prescription and non-prescription medications that contain alcohol. Do not drink alcohol while you are taking Robaxisal C ½. It can lead to:

  • drowsiness
  • unusually slow or weak breathing
  • serious side effects or
  • a fatal overdose
• other sedative drugs which may enhance the drowsiness caused by Robaxisal C ½.
• other opioid analgesics (drugs used to treat pain)
• general anesthetics (drugs used during surgery)
• benzodiazepines (drugs used to help you sleep or that help reduce anxiety)
• antidepressants (for depression and mood disorders). Do not take Robaxisal C ½ with MAO inhibitors (MAOi) or if you have taken MAOi’s in the last 14 days.
• antiepileptics (medicines used to prevent and control seizures e.g., gabapentinoids such as gabapentin and pregabalin).
• drugs used to treat serious mental or emotional disorders (such as schizophrenia)
• antihistamines (drugs used to treat allergies)
• anti-emetics (drugs used for the prevention of vomiting)
• drugs used to treat muscle spasms and back pain
• tranquilizers, sedatives, sedating antihistamines, other depressants, other salicylates
• some heart medications (such as beta blockers)
• drugs used to treat migraines (eg. triptans)
• warfarin (such as Coumadin) and other anticoagulants (used for prevention or treatment of blood clots)
• St. John’s Wort

How to take Robaxisal C ½:

Robaxisal C ½ should not be used in children less than 12 years old.

Codeine, including Robaxisal C ½, should be prescribed at the lowest effective dose for the shortest period of time. Dosing should be as needed every 6 to 8 hours and not on scheduled intervals.

Adults

1 or 2 caplets every 6-8 hours. Do not exceed 8 caplets in 24 hours.

Swallow whole. Do not cut, break, crush, chew or dissolve the tablet. This can be dangerous and can lead to death or seriously harm you.

Usual Adult Starting Dose:

Your dose is personalized just for you. Be sure to follow your doctor’s dosing instructions exactly. Do not increase or decrease your dose without consulting your doctor.

Your doctor will prescribe the lowest dose that works to control your pain. It is recommended that you only take Robaxisal C ½ for up to 7 days. If you need to take Robaxisal C ½ for longer, your doctor will determine the best dose for you to lower the risk of side effects and overdose. Higher doses can lead to more side effects and a greater chance of overdose.

Review your pain regularly with your doctor to determine if you still need Robaxisal C ½. Be sure to use Robaxisal C ½ only for the condition for which it was prescribed.

If your pain increases or you develop any side effect as a result of taking Robaxisal C ½, tell your doctor immediately.

Stopping your Medication

If you have been taking Robaxisal C ½ for more than a few days, you should not stop taking it all of a sudden. Your doctor will monitor and guide you on how to slowly stop taking Robaxisal C ½. You should do it slowly to avoid uncomfortable symptoms such as having:

• body aches
• diarrhea
• goosebumps
• loss of appetite
• nausea
• feeling nervous or restless
• runny nose
• sneezing
• tremors or shivering
• stomach cramps
• rapid heart rate (tachycardia)
• having trouble sleeping
• an unusual increase in sweating
• heart palpitations
• an unexplained fever
• weakness
• yawning

By reducing or stopping your opioid treatment, your body will become less used to opioids. If you start treatments again, you will need to start at the lowest dose. You may overdose if you restart at the last dose you took before you slowly stopped taking Robaxisal C ½.

Refilling your Prescription for Robaxisal C ½:

A new written prescription is required from your doctor each time you need more Robaxisal C ½. Therefore, it is important that you contact your doctor before your current supply runs out.

Only obtain prescriptions for this medicine from the doctor in charge of your treatment. Do not seek prescriptions from other doctors unless you switch to another doctor for your pain management.

Overdose:

Signs of overdose may include:

• unusually slow or weak breathing
• dizziness
• confusion
• extreme drowsiness
• pinpoint pupils
• nausea and vomiting
• low blood pressure

Missed Dose:

If you miss one dose, take it as soon as possible. However, if it is almost time for your next dose, then skip the missed dose. Do not take two doses at once. If you miss several doses in a row, talk to your doctor before restarting your medication.

What are possible side effects from using Robaxisal C ½?

These are not all the possible side effects you may feel when taking Robaxisal C ½. If you experience any side effects not listed here, contact your healthcare professional.

Side effects may include:

• Drowsiness
• Insomnia
• Dizziness
• Fainting
• Nausea, vomiting, or a poor appetite.
• Dry mouth
• Headache
• Problems with vision
• Weakness, uncoordinated muscle movement
• Itching
• Sweating
• Constipation
• Low sex drive, impotence (erectile dysfunction), infertility

Talk with your doctor or pharmacist about ways to prevent constipation when you start using Robaxisal C ½.

Serious side effects and what to do about them

Serious side effects and what to do about them

If you have a troublesome symptom or side effect that is not listed here or becomes bad enough to interfere with your daily activities, talk to your healthcare professional.

Reporting Side Effects

Storage:

• Keep unused or expired Robaxisal C ½ in a secure place to prevent theft, misuse, or accidental exposure.
• Store at room temperature (15-30°C).
• Keep Robaxisal C ½ under lock, out of sight and reach of children and pets.
• Never take medicine in front of small children as they will want to copy you. Accidental ingestion by a child is dangerous and may result in death. If a child accidentally takes Robaxisal C ½, get emergency help right away.

Disposal:

Robaxisal C ½ should never be thrown into household trash, where children and pets may find it. It should be returned to a pharmacy for proper disposal.

If you want more information about Robaxisal C ½:

• Talk to your healthcare professional.
• Find the full product monograph that is prepared for healthcare professionals and includes this consumer medication information by visiting the Health Canada website (https://health-products.canada.ca/dpd-bdpp/), or by contacting the sponsor, GlaxoSmithKline Consumer Healthcare ULC, Mississauga, Ontario L5R 4B2, or by calling 1-888-275-9938.

Last Revised: March 5, 2024