Zidovudine (Systemic)

Brand Names : Retrovir, Apo-Zidovudine, Novo-AZT, AZT

Before Using This Medicine

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 zidovudine, the following should be considered:

Allergies - Tell your doctor if you have ever had any unusual or allergic reaction to zidovudine. Also tell your health care professional if you are allergic to any other substances, such as foods, preservatives, or dyes.

Pregnancy - Zidovudine crosses the placenta. Studies in pregnant women have shown that zidovudine decreases the chance of passing HIV to your baby during pregnancy and at birth. In these studies, zidovudine did not increase the occurrence of birth defects. In most studies in animals, zidovudine has not been shown to cause birth defects except at extremely high doses; however, it has been shown to decrease the number of successful pregnancies in rats and rabbits at doses many times higher than human doses.

Breast-feeding - Zidovudine passes into breast milk. Breast-feeding is usually not recommended in patients with HIV infection because of the risk of passing HIV to the infant.

Children - Zidovudine can cause serious side effects in any patient. Therefore, it is especially important that you discuss with your child's doctor the good that this medicine may do as well as the risks of using it. Your child must be carefully followed, and frequently seen, by the doctor while he or she is taking zidovudine.

Older adults - Zidovudine has not been studied specifically in older people. Therefore, it is not known whether it causes different side effects or problems in the elderly than it does in younger adults.

Other medicines - 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 zidovudine, it is especially important that your health care professional know if you are taking any of the following:

• Amphotericin B by injection (e.g., Fungizone) or
• Antineoplastics (cancer medicine) or
• Antithyroid agents (medicine for overactive thyroid) or
• Azathioprine (e.g., Imuran) or
• Chloramphenicol (e.g., Chloromycetin) or
• Colchicine or
• Cyclophosphamide (e.g., Cytoxan) or
• Flucytosine (e.g., Ancobon) or
• Ganciclovir (e.g., Cytovene) or
• Interferon (e.g., Intron A, Roferon-A) or
• Mercaptopurine (e.g., Purinethol) or
• Methotrexate (e.g., Mexate) or
• Plicamycin (e.g., Mithracin) - Caution should be used if these medicines and zidovudine are used together; taking zidovudine while you are using or receiving these medicines may make anemia and other blood problems worse

• Clarithromycin (e.g., Biaxin) - Clarithromycin may decrease the amount of zidovudine in the blood

• Probenecid (e.g., Benemid) - Probenecid may increase the amount of zidovudine in the blood, increasing the chance of side effects

• Doxorubicin (e.g., Adriamycin) or
• Ribavirin (e.g., Virazole) - These medicines may cause zidovudine to be less effective

Other medical problems - The presence of other medical problems may affect the use of zidovudine. Make sure you tell your doctor if you have any other medical problems, especially:

• Anemia or other blood problems - Zidovudine may make these conditions worse

• Liver disease - Patients with liver disease may have an increase in side effects from zidovudine

• Low amounts of folic acid or vitamin B₁₂ in the blood - Zidovudine may worsen anemia caused by a decrease of folic acid or vitamin B₁₂