What is Zidovudine?

Commonly Used Brand Name(s)Retrovir

Therapeutic ClassificationsAntiretroviral Agent

Pharmacologic ClassificationsNucleoside Reverse Transcriptase Inhibitor

Blackbox WarningTOP

Oral route (Capsule;Tablet;Syrup)

Zidovudine has been associated with hematologic toxicity, including neutropenia and severe anemia, particularly in patients with advanced HIV disease. Prolonged use of zidovudine has been associated with symptomatic myopathy. Lactic acidosis and severe hepatomegaly with steatosis, including fatal cases, have been reported. Suspend treatment if clinical or laboratory findings suggestive of lactic acidosis or pronounced hepatotoxicity occur .

OverviewTOP

Zidovudine (also known as AZT) is used in combination with other anti-virus medicines for the treatment of human immunodeficiency virus (HIV) infection. HIV is the virus that causes acquired immune deficiency syndrome (AIDS). Zidovudine is used to slow the progression of disease in patients infected with HIV who have advanced symptoms, early symptoms, or no symptoms at all. This medicine also is used to help prevent pregnant women who have HIV from passing the virus to their babies during pregnancy and at birth.

Zidovudine will not cure or prevent HIV infection or AIDS. It helps keep HIV from reproducing and appears to slow down the destruction of the immune system. This may help delay the development of problems usually related to AIDS or HIV disease. Zidovudine will not keep you from spreading HIV to other people. People who receive this medicine may continue to have the problems usually related to AIDS or HIV disease.

This medicine is available only with your doctor's prescription.

Proper UseTOP

Take this medicine exactly as directed by your doctor. Do not take more of it, do not take it more often, and do not take it for a longer time than your doctor ordered. Also, do not stop taking this medicine without checking with your doctor first.

This medicine comes with a patient information sheet. Read and follow the instructions carefully. Ask your doctor if you have any questions.

Keep taking zidovudine for the full time of treatment, even if you begin to feel better. Only take medicine that your doctor has prescribed specifically for you. Do not share your medicine with other people.

For patients using zidovudine oral solution:

Shake the oral solution before use. Use a specially marked measuring spoon or other device to measure each dose accurately. The average household teaspoon may not hold the right amount of liquid.

This medicine works best when there is a constant amount in the blood. To help keep the amount constant, do not miss any doses. If you need help in planning the best times to take your medicine, check with your doctor.

DosingTOP

The dose of this medicine will be different for different patients. Follow your doctor's orders or the directions on the label. The following information includes only the average doses of this medicine. If your dose is different, do not change it unless your doctor tells you to do so.

The amount of medicine that you take depends on the strength of the medicine. Also, the number of doses you take each day, the time allowed between doses, and the length of time you take the medicine depend on the medical problem for which you are using the medicine.

For HIV infection:
- For oral dosage forms (capsules, solution, and tablets):
  - Adults—600 milligrams (mg) a day in divided doses in combination with other anti-virus medicine.
  - Children and infants 4 weeks of age and older—Dose is based on body weight or body size and must be determined by your child's doctor. The recommended dose is 18 to 24 milligrams (mg) per kilogram (kg) per day of body weight or 600 mg per day or 480 milligrams per square meter of body surface area (mg/m²) a day in divided doses.
To help prevent pregnant women from passing HIV to their babies during pregnancy and at birth:
- For oral dosage form (capsules):
  - Pregnant women (after 14 weeks of pregnancy, up to the start of labor)—100 milligrams (mg) five times a day, 200 mg every eight hours, or 300 mg every twelve hours until the start of labor.
- For oral dosage form (solution):
  - Pregnant women (after 14 weeks of pregnancy, up to the start of labor)—100 milligrams (mg) five times a day, 200 mg every eight hours, or 300 mg every twelve hours until the start of labor.
  - Newborn infants—Dose is based on body weight and must be determined by your doctor. The usual dose is 2 milligrams (mg) per kilogram (kg) (0.9 mg per pound) of body weight every six hours starting within eight to twelve hours of birth and continuing through 6 weeks of age.

Missed DoseTOP

If you miss a dose of this medicine, take it as soon as possible. However, if it is almost time for your next dose, skip the missed dose and go back to your regular dosing schedule. Do not double doses.

Use & StorageTOP

Store the medicine in a closed container at room temperature, away from heat, moisture, and direct light. Keep from freezing.

Keep out of the reach of children.

Do not keep outdated medicine or medicine no longer needed.

Ask your healthcare professional how you should dispose of any medicine you do not use.

Before UsingTOP

In deciding to use a medicine, the risks of taking the medicine must be weighed against the good it will do. This is a decision you and your doctor will make. For this medicine, the following should be considered:

AllergiesTOP

Tell your doctor if you have ever had any unusual or allergic reaction to this medicine or any other medicines. Also tell your health care professional if you have any other types of allergies, such as to foods, dyes, preservatives, or animals. For non-prescription products, read the label or package ingredients carefully.

PediatricTOP

Appropriate studies performed to date have not demonstrated pediatric-specific problems that would limit the usefulness of zidovudine in children.

GeriatricTOP

Appropriate studies performed to date have not demonstrated geriatric-specific problems that would limit the usefulness of this medicine in the elderly. However, elderly patients are more likely to have age-related liver, kidney, or heart problems which may require caution and an adjustment in the dose for patients receiving zidovudine.

PregnancyTOP

	Pregnancy Category	Explanation
All Trimesters	C	Animal studies have shown an adverse effect and there are no adequate studies in pregnant women OR no animal studies have been conducted and there are no adequate studies in pregnant women.

Breast FeedingTOP

There are no adequate studies in women for determining infant risk when using this medication during breastfeeding. Weigh the potential benefits against the potential risks before taking this medication while breastfeeding.

Drug InteractionsTOP

Although certain medicines should not be used together at all, in other cases two different medicines may be used together even if an interaction might occur. In these cases, your doctor may want to change the dose, or other precautions may be necessary. When you are taking this medicine, it is especially important that your healthcare professional know if you are taking any of the medicines listed below. The following interactions have been selected on the basis of their potential significance and are not necessarily all-inclusive.

Using this medicine with any of the following medicines is usually not recommended, but may be required in some cases. If both medicines are prescribed together, your doctor may change the dose or how often you use one or both of the medicines.

Using this medicine with any of the following medicines may cause an increased risk of certain side effects, but using both drugs may be the best treatment for you. If both medicines are prescribed together, your doctor may change the dose or how often you use one or both of the medicines.

Acetaminophen
Fluconazole
Interferon Beta-1a
Methadone
Nelfinavir
Probenecid
Rifabutin
Rifampin
Rifapentine
Tipranavir
Valproic Acid

Other InteractionsTOP

Certain medicines should not be used at or around the time of eating food or eating certain types of food since interactions may occur. Using alcohol or tobacco with certain medicines may also cause interactions to occur. Discuss with your healthcare professional the use of your medicine with food, alcohol, or tobacco.

PrecautionsTOP

It is very important that your doctor check your or your child's progress at regular visits to make sure that this medicine is working properly. Blood tests may be needed to check for unwanted effects.

Zidovudine may cause blood problems. These problems may result in a greater chance of certain infections and slow healing. Therefore, you should be careful when using regular toothbrushes, dental floss, and toothpicks not to damage your gums. Check with your medical doctor or dentist if you have any questions about proper oral hygiene (mouth care) during treatment.

Zidovudine may cause some serious side effects, including bone marrow problems. Symptoms of bone marrow problems include fever, chills, or sore throat; pale skin; and unusual tiredness or weakness. These problems may require blood transfusions or temporarily stopping treatment with zidovudine. Check with your doctor if any new health problems or symptoms occur while you or your child are taking zidovudine.

HIV may be acquired from or spread to other people through infected body fluids, including blood, vaginal fluid, or semen. If you are infected, it is best to avoid any sexual activity involving an exchange of body fluids with other people. If you do have sex, always wear (or have your partner wear) a condom (“rubber”). Only use condoms made of latex, and use them every time you have vaginal, anal, or oral sex. The use of a spermicide (such as nonoxynol-9) may also help prevent the spread of HIV if it is not irritating to the vagina, rectum, or mouth. Spermicides have been shown to kill HIV in lab tests. Do not use oil-based jelly, cold cream, baby oil, or shortening as a lubricant—these products can cause the condom to break. Lubricants without oil, such as K-Y Jelly, are recommended. Women may wish to carry their own condoms. Birth control pills and diaphragms will help protect against pregnancy, but they will not prevent someone from giving or getting the AIDS virus. If you inject drugs, get help to stop. Do not share needles with anyone. In some cities, more than half of the drug users are infected, and sharing even one needle can spread the virus. If you have any questions about this, check with your doctor.

Two rare but serious reactions to this medicine are lactic acidosis (too much acid in the blood) and liver toxicity, which includes an enlarged liver. These are more common if you are female, very overweight (obese), or have been taking anti-HIV medicines for a long time. Call your doctor right away if you or your child have more than one of these symptoms: abdominal discomfort or cramping; dark urine; decreased appetite; diarrhea; general feeling of discomfort; light-colored stools; muscle cramping or pain; nausea; unusual tiredness or weakness; trouble breathing; vomiting; or yellow eyes or skin.

When you or your child start taking HIV medicines, your immune system may get stronger. If you have infections that are hidden in your body (e.g., pneumonia or tuberculosis), you may notice new symptoms when your body tries to fight them. If this occurs, tell your doctor right away.

This medicine may cause you or your child to have excess body fat. Tell your doctor right away if you notice changes in your body shape, including an increased amount of body fat in the neck or upper back, face, around the chest, or stomach area. You might also lose fat from your legs, arms, or face.

Do not take other medicines unless they have been discussed with your doctor. This includes prescription or nonprescription (over-the-counter [OTC]) medicines and herbal or vitamin supplements.