Patient Medication Information: uses, side effects, how to take - Retrovir (Azt) (Viiv Healthcare, 100 mg)
Serious Warnings and Precautions
WARNING: RISK OF HEMATOLOGICAL TOXICITY, MYOPATHY, LACTIC ACIDOSIS Hematologic Toxicity (decrease in bone marrow and blood cells) RETROVIR (zidovudine) tablets, capsules, syrup, and injection have been associated with hematologic toxicity including neutropenia (low neutrophils - type of white blood cell) and severe anemia (lowered red blood cell count). This is more common in patients with advanced HIV-1 disease. Myopathy (disease of the muscle) Long term use of RETROVIR has been associated with myopathy (muscle pain, aching or weakness). Lactic Acidosis (high level of acid in the blood) and Severe Hepatomegaly (swollen and enlarged liver) Lactic acidosis and severe hepatomegaly with steatosis (buildup of fat in the liver), including fatal cases, have been reported with the use RETROVIR and other antiretrovirals. Your Healthcare Professional will stop your treatment if clinical or laboratory findings are suggestive of lactic acidosis or pronounced hepatotoxicity (liver damage). |
What is RETROVIR (AZT) used for?
RETROVIR (AZT) is used to treat Human Immunodeficiency Virus (HIV) infection. It is used in combination with other antiretroviral drugs. RETROVIR (AZT) is also used to prevent HIV infection from being passed on from a woman to her baby during pregnancy, labour or after birth.
How does RETROVIR (AZT) work?
RETROVIR (AZT) contains the medicinal ingredient zidovudine. This belongs to a group of antiretroviral medicines called nucleoside analogue reverse transcriptase inhibitors (NRTIs), which are used to treat HIV infection.
HIV is a retrovirus (a type of virus). Infection with HIV damages the immune system and can lead to Acquired Immune Deficiency Syndrome (AIDS) and other related illnesses.
RETROVIR (AZT) does not cure HIV infection, it reduces the amount of virus in your body, and keeps it at a low level. It also increases the CD4 cell count in your blood. CD4 cells are a type of white blood cells that are important in helping your body to fight infection.
What are the ingredients in RETROVIR (AZT)?
Capsules
Medicinal ingredient: zidovudine
Non-medicinal ingredients: corn starch, gelatin, magnesium stearate, microcrystalline cellulose, sodium starch glycolate and titanium dioxide.
Syrup
Medicinal ingredient: zidovudine
Non-medicinal ingredients: artificial candied sugar flavor, citric acid, glycerine, purified water, sodium benzoate (0.2%) added as a preservative, sodium hydroxide, strawberry flavour, sucrose.
Solution for Infusion
Medicinal ingredient: zidovudine
Non-medicinal ingredients: hydrochloric acid or sodium hydroxide water for injection. RETROVIR (AZT) Solution for Infusion contains no preservatives.
RETROVIR (AZT) comes in the following dosage forms:
Capsules: 100 mg
Syrup: 50 mg/5mL
Solution for infusion: 10 mg/mL
Do not use RETROVIR (AZT) if:
- You have, or have ever had life-threatening allergic reactions to this drug or to any ingredient in the formulation, including any non-medicinal ingredients, or component of the container.
- You have neutropenia (low neutrophil counts - type of white blood cell) or low hemoglobin levels (blood component which carries oxygen in the blood).
To help avoid side effects and ensure proper use, talk to your healthcare professional before you take RETROVIR (AZT). Talk about any health conditions or problems you may have, including if:
- You are allergic to any ingredient in this medicine.
- you have bone marrow problems (low blood cell counts).
- you have hepatomegaly (enlarged liver) with steatosis (buildup of fat in the liver), hepatitis (inflamed liver), other hepatic impairments (liver problems) or other known risk factors for liver disease. Your healthcare professional may periodically do blood tests to check your liver function while you are taking RETROVIR (AZT).
- you have kidney disease.
- you are taking other drugs (see The following may interact with RETROVIR (AZT))
- you are pregnant or breastfeeding.
- your baby or infant was exposed to Nucleoside Reverse Transcriptase Inhibitors (NRTIs) during pregnancy or labour.
- you are taking ribavarin as it could cause or worsen anemia (symptoms of tiredness, shortness of breath). Your healthcare professional will advise whether you should stop taking RETROVIR (AZT).
Other warnings you should know about:
RETROVIR (AZT) can cause serious side effects, including:
- Lactic Acidosis and Severe Liver Problems: The class of medicines to which RETROVIR (AZT) belongs (NRTIs) can cause a condition called lactic acidosis (excess of lactic acid in your blood), together with an enlarged liver. Symptoms of lactic acidosis include feeling of weakness, loss of appetite, sudden unexplained weight loss, upset stomach and difficulty breathing or rapid breathing. This rare, but serious side effect occurs more often in women. If you have liver problems you may also be more at risk of getting this condition. If you experience any of these symptoms, stop taking RETROVIR (AZT) and talk to your healthcare professional.
- Lipoatrophy: You may experience lipoatrophy (loss of fat) in your face, limbs and buttocks while taking RETROVIR (AZT). Your healthcare professional will assess you regularly for signs of lipoatrophy.
Blood Disorders such as anemia (low red blood cells count), leucopenia (low white blood cells count), neutropenia (low levels of neutrophils – a type of white blood cell) and rarely red cell aplasia (reduction in number of red blood cells).
If your hemoglobin or neutrophil (type of white blood cell) levels become too low, your healthcare professional may lower your dose of RETROVIR (AZT). Your healthcare professional may also stop your treatment of RETROVIR (AZT).
Immune Reconstitution Inflammatory Syndrome: Changes to your immune system can happen when you start taking HIV-1 medicines. Your immune system may get stronger and begin to fight infections that have been hidden in your body for a long time.
Autoimmune disorders happen when the immune system attacks healthy body tissue. This may happen after you start taking medicines for HIV infection. Examples of this include: Grave's disease (which affects the thyroid gland), Guillain-Barré syndrome (which affects the nervous system), polymyositis (which affects the muscles), or autoimmune hepatitis (which affects the liver). Autoimmune disorders may occur many months after the start of treatment.
- Risk of Infections: You may continue to develop other infections and other illnesses associated with HIV while you are taking RETROVIR (AZT). You should therefore keep in regular contact with your healthcare professional.
See the Serious side effects and what to do about them table, below, for more information on these and other serious side effects.
Blood Tests: Your blood sugar levels (glucose) or level of fats (lipids) in your blood may increase with HIV treatment. Your healthcare professional will decide when to do blood tests, to check for these and other side effects, and will interpret the results.
Myopathy: If you use RETROVIR (AZT) for a long time, you may develop myopathy or myositis. These are muscle diseases.
Solution for Infusion
The rubber stopper of the RETROVIR (AZT) intravenous vials contains latex. Tell your healthcare professional if you are allergic to latex.
Pregnancy and Newborns:
If you are pregnant, planning to become pregnant, or become pregnant while taking RETROVIR (AZT), talk to your healthcare professional before taking RETROVIR (AZT). It is not known if RETROVIR (AZT) can harm your unborn child. You and your healthcare professional will need to decide if taking RETROVIR (AZT) is right for you. If you take RETROVIR (AZT) while you are pregnant, talk to your healthcare professional about how you can be included in the Antiretroviral Pregnancy Registry.
For pregnant women who are considering the use of RETROVIR (AZT) during pregnancy for the prevention of HIV-transmission to their infants, it is important to understand that transmission may still occur in some cases (about 8%) despite using RETROVIR (AZT). The long-term safety of using RETROVIR (AZT) in fetuses, neonates, or infants is not known.
Babies exposed to Nucleoside Reverse Transcriptase Inhibitors (NRTIs) during pregnancy or labour show minor temporary increases in blood levels of lactate. There have been very rare reports of diseases that affect the nervous system such as delayed development and seizures.
These findings do not affect current recommendations to use RETROVIR (AZT) in pregnant women to prevent transmission of HIV to their babies. Talk to your healthcare professional to determine if RETROVIR (AZT) is right for you.
Breastfeeding: HIV-infected women should not breastfeed in order to prevent transmission of HIV to a child who may not yet be infected. The ingredients in RETROVIR (AZT) can also pass into your breast- milk. If you are breastfeeding or planning to breastfeed, talk with your healthcare professional about the best way to feed your baby.
Infecting Others with HIV: RETROVIR (AZT) will not stop you from passing HIV to others. The risk is lower if you take your HIV medicine as instructed by your healthcare professional. However, you should still take steps to avoid infecting others by:
- Using condoms when you have oral or penetrative sex.
- Not reusing or sharing needles, syringes, or other injection equipment.
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 RETROVIR (AZT):
- atovaquone, used to treat parasitic infections such as PCP
- one marrow suppressive agents/cytotoxic agents (such as doxorubicin), used to treat cancer
- clarithromycin or rifampin or trimethoprim-sulfamethoxazole, used as an antibiotics
- fluconazole, used to treat fungal infections
- ganciclovir or interferon-alpha or acyclovir or ribavirin , used to treat virus infections
- lamivudine or stavudine, used to treat HIV infection
- methadone, used as a heroin substitute
- phenytoin, used for treating epilepsy
- probenecid, used to treat gout and similar conditions, and given with some antibiotics to make them more effective
- valproic acid, used to treat seizure disorders
- pyrimethamine, used to treat malaria
How to take RETROVIR (AZT):
- Take RETROVIR (AZT) exactly as directed by your healthcare professional. If you are unsure about how to take it, ask your doctor or pharmacist.
Usual dose:
Oral Administration
Adults and Adolescents 30 kg and Over: 600 mg daily in combination with other antiretroviral agents
- Capsules: three 100 mg RETROVIR (AZT) capsules every 12 hours; OR two 100 mg RETROVIR (AZT) capsules every 8 hours.
- Syrup: 6 teaspoonfuls (30 mL) RETROVIR (AZT) syrup every 12 hours; OR 4 teaspoonfuls (20 mL) RETROVIR (AZT) syrup every 8 hours.
Children and Adolescents weighing at least 4 kg
The recommended oral dose in children weighing at least 4 kg is provided in the table below.
Children should be assessed for the ability to swallow capsules. If a child has difficulty in swallowing a RETROVIR (AZT) capsule, the RETROVIR (AZT) syrup formulation should be used.
RETROVIR (AZT) Syrup is available for dosing children who weigh less than 30 kg. RETROVIR (AZT) Syrup should be used to provide accurate dosage when capsules are not appropriate.
Recommended Dosage of RETROVIR (AZT) in Children and Adolescents weighing at least 4 kg
Body Weight (kg) | Total Daily Dose | Dosage Regimen and Dose | ||||
| (Twice daily) | (three times daily). | |||||
| 4 to less than 9 | 24 mg/kg/day | 12 mg/kg (1.2 mL/kg) | 8 mg/kg (0.8 mL/kg) | |||
| 9 to less than 30 | 18 mg/kg/day | 9 mg/kg (0.9 mL/kg) | 6 mg/kg (0.6 mL/kg) | |||
| 30 or more | 600 mg/day | 300 mg (30 mL) | 200 mg (20 mL) | |||
Alternatively, dosing for RETROVIR can be based on body surface area (BSA) for each child. The usual dose of RETROVIR is 480 mg/m2 per day, divided equally into two or three doses per day. In some cases the dose calculated by mg for each kg will not be the same as that calculated by BSA.
Children weighing less than 4 kg and/or children less and 3 months old
The safety and how well RETROVIR (AZT) syrup works in children infected with HIV weighing less than 4 kg has not been determined. The safety and how well RETROVIR (AZT) solution for infusion works in children infected with HIV less than 3 months old has not been determined.
Solution for Infusion
Adults and Adolescents weighing at least 30 kg
The recommended dose is 1 to 2 mg/kg administered as a 1 hour infusion every 4 hours around the clock (6 times daily). RETROVIR (AZT) solution for infusion is administered intravenously at a constant rate over 1 hour. Rapid infusion or bolus injection should be avoided. RETROVIR (AZT) solution for infusion should not be given intramuscularly.
If you are also taking clarithromycin, your doctor may advise you to take this medication at least 2 hours before or 2 hours after RETROVIR (AZT), to avoid a drug interaction.
Children at least 3 months of age to 12 months of age
120 mg/m2 every 6 hours, infused over 1 hour (480 mg/m2 per day). Do not exceed 160 mg for any individual dose.
Prevention of Maternal-Fetal HIV Transmission
The recommended dosing regimen for administration to pregnant women (greater than 14 weeks of pregnancy) and their newborn infant is:
- Maternal Dosing: 100 mg orally 5 times per day until the start of labour. During labour and delivery, intravenous RETROVIR (AZT) should be administered at 2 mg/kg (total body weight) over 1 hour followed by a continuous intravenous infusion at 1 mg/kg/h (total body weight) until clamping of the umbilical cord.
- Newborn Infant Dosing: 2 mg/kg (0.2 mL/kg) of syrup every 6 hours starting within 12 hours after birth and continuing through 6 weeks of age. The amount of liquid medicine to be given to the infant is very small and an appropriate sized dosing syringe with 0.1 mL graduation should be used. Infants unable to receive oral dosing may be administered RETROVIR (AZT) intravenously at 1.5 mg/kg, infused over 30 minutes, every 6 hours.
Overdose:
| If you think you, or a person you are caring for, have taken too much RETROVIR (AZT), contact a healthcare professional, hospital emergency department, or regional poison control centre immediately, even if there are no symptoms. |
Missed Dose: It is important to take this medicine as prescribed to ensure you get maximum benefit. If you forget to take a dose, take it as soon as you remember, and then continue as before. Do not take a double dose to make up for forgotten individual doses.
What are possible side effects from using RETROVIR (AZT)?
These are not all the possible side effects you may have when taking RETROVIR (AZT). If you experience any side effects not listed here, tell your healthcare professional.
Like all medicines, RETROVIR (AZT) can have side effects. When treating HIV infection, it is not always possible to tell whether some of the side effects that occur are caused by RETROVIR (AZT), by other medicines you are taking at the same time or by the HIV infection. For this reason it is very important that you inform your healthcare professional about any changes in your health.
Side effects may include:
- nausea (feeling sick)
- Vomiting.
- Fever.
- Headache.
- Stomach pain.
- Loss of appetite.
- Muscle pain.
- Decrease in the number of cells involved in blood clotting (thrombocytopenia) or in all kinds of blood cells (pancytopenia), reduction in the number of red blood cells (pure red cell aplasia).
- Failure of the bone marrow to produce new blood cells (aplastic anemia).
- An increase in lactic acid.
- Feeling depressed or anxious.
- Dizziness.
- Not being able to sleep.
- Tingly feelings in the skin (pins and needles).
- Not being able to concentrate.
- Feeling drowsy.
- Seizures.
- Disease of the heart muscle.
- Cough.
- Intestinal gas.
- Changes in the colour of the nails, skin, or the skin inside the mouth.
- Taste disturbance.
- Indigestion.
- Skin rash (red, raised or itchy skin).
- Sweating.
- Passing urine more often.
- Enlarged breasts in men.
- General aches and pain.
- Chills.
- Chest pain.
- Flu-like feeling.
If these become bothersome, consult your healthcare professional
An important but reversible side effect of RETROVIR (AZT), particularly in patients with more severe disease, can be a decrease in certain types of blood counts (including red blood cells, white blood cells and platelets) and increase in certain liver enzymes. Since a reduction in these cells can directly affect your health, it is important to have your blood tested as often as your doctor requests it. In some cases, it may be necessary to adjust the dose of the drug, temporarily discontinue the drug, give a blood transfusion, or stop the drug altogether.
It is important to understand that although these blood effects can occur at any stage, they are much more common in advanced disease and in patients who start RETROVIR (AZT) therapy late in their illness.
Serious side effects and what to do about them
| Symptom / effect | Talk to your healthcare professional | Stop taking drug and get immediate medical help | |
|---|---|---|---|
| Only if severe | In all cases | ||
| COMMON | |||
| Anemia (Lowered red blood cell count): fatigue, breathlessness. Neutropenia (Low white blood cell count): making you more prone to infections. | ✓ | ||
| RARE | |||
| Pancreatitis (inflammation of the pancreas) and hepatitis (inflammation of the liver): nausea, vomiting, and severe stomach cramps. | ✓ | ||
| Lactic acidosis (high level of acid in the blood): weight loss, fatigue, malaise, abdominal pain, shortness of breath. | ✓ | ||
Serious side effects and what to do about them
| Symptom / effect | Talk to your healthcare professional | Stop taking drug and get immediate medical help |
|---|
| Only if severe | In all cases | ||
|---|---|---|---|
| Severe hepatomegaly (swollen and enlarged liver): with symptoms of liver problems such as nausea, vomiting, abdominal pain, weakness and diarrhea. | ✓ | ||
| FREQUENCY NOT KNOWN | |||
| Lipoatrophy (loss of fat from legs, arms and face): loss of fat from your legs, arms, and face. | ✓ | ||
| Immune Reconstitution Inflammatory Syndrome and Autoimmune Disorders: fever, redness, rash or swelling, fatigue, joint or muscle pain , numbness or weakness beginning in the hands and feet and moving up towards the trunk of the body, palpitations, chest pain or rapid heart rate, yellowing of the eyes and skin | ✓ | ||
If you have a troublesome symptom or side effect that is not listed here or becomes bad enough to interfere with your daily activities, tell your healthcare professional.
Reporting Side Effects
You can report any suspected side effects associated with the use of health products to Health Canada by:
NOTE: Contact your health professional if you need information about how to manage your side effects. The Canada Vigilance Program does not provide medical advice. |
Storage:
RETROVIR (AZT) Capsules should be stored at room temperature between 15º and 25ºC and protected from light and moisture.
RETROVIR (AZT) Syrup should be stored at 15º to 25ºC and protected from light. Discard one month after first opening.
RETROVIR (AZT) Solution for Infusion should be stored at room temperature between 15º and 25ºC and protected from light. Do not freeze.
Do not take your medicine after the expiry date shown on the bottle and/or the carton.
Keep out of reach and sight of children.
If you want more information about RETROVIR (AZT):
- Talk to your healthcare professional
- Find the full product monograph that is prepared for healthcare professionals and includes this Patient Medication Information by visiting the Health Canada website: (https://www.canada.ca/en/health-canada/services/drugs-health-products/drug-products/drug-product-database.html); the manufacturer’s website http://www.viivhealthcare.ca, or by calling 1-877-393-8448.
Last Revised June 9, 2021
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