ZIDOVIR
ZIDOVUDINE · by A. J. MIRZA
Composition
Cap 100 mg/250 mg: Zidovudine 100 mg/250 mg. Tab 300 mg: Zidovudine 300 mg. Oral Soln: Per 5 ml: Zidovudine 50 mg.
Indications & Dosage
HIV infection in combination with other antiretroviral drugs: Adults & Children 12 yrs: 30 kg body-weight: 250-300 mg twice daily in combination with other antiretrovirals. Children 4-8 kg body-weight: use oral soln; 8-13 kg body-weight: 100 mg twice daily; 14-21 kg body-weight: 100 mg in the morning and 200 mg in the evening; 22-30 kg body-weight: 200 mg twice daily; 28-30 kg body-weight: 250 mg twine daily. Prevention of maternal-fetal HIV transmission: ORAL OR BY IV INF: Adults: 100 mg orally five times daily to mother until beginning of labour, then 2 mg/ kg over 1 hr by IV INF during labour and delivery, followed by 1 mg/kg per hr until cord is clamped. Then to baby, 2 mg/kg orally every 6 hr (or 1.5 mg/kg by IV INF over 30 min every 6 hr) starting within 12 hr after birth and continuing until 6 week old. HIV infection in combination with other antiretroviral drugs in patients temporarily unable to take zidovudine by mouth: BY IV INF: Adult: 0.8-1 mg/kg every 4 hours usually for not more than 2 weeks, dose approximating to 1.2-1.5 mg/kg every 4 hours by mouth.
Contraindications
: Acute porphorias, low neutrophil cell counts or low haemoglobin levels, neonates with hyperbilirubinaemia or increased transaminase levels.
Precautions
Elderly, lactic acidosis, risk of haematological toxicity particularly with high dose and advanced disease, vitamin B12 deficiency (increased risk of neutropenia). Perform blood tests at least every 2 weeks (weekly for infusion) for first three months of therapy and at least monthly thereafter it patient has advanced disease. Adjust dose if anaemia or myelosuppression occurs or is present. Renal or hepatic impairment, pancreatitis, risk of immune reactivation syndrome in patients with severe immune deficiency within first few weeks or months of starting combination antiretroviral therapy, Pregnancy under 14 weeks gestation (only if benefit to mother outweighs risk to foetus). Discontinue if aminotransferase levels rapidly elevating or with progressive hepatomegaly or metabolic lactic acidosis of unknown aetiology. Advise patients to report benign digestive symptoms, respiratory symptoms or neurological symptoms indicative of lactic acidosis development. Risk of osteonecrosis; monitor for signs of joint pain or immobility.
Interactions
Chronic administration of analgesics, particularly paracetamol. Drugs affecting hepatic glucuronidation or inhibiting hepatic microsomal enzymes, other potentially nephrotoxic or myelosuppressive drugs, Probenecid; monitor closely for haematological toxicity, Phenytoin, ribavirin, stavudine, fluconazole, valproic acid, methadone, rifampicin
Side Effects
Anaemia, anxiety, chest pain, convulsions, depression, dizziness, drowsiness, gynaecomastia, influenza-like symptoms, lactic acidosis, lipodystrophy, loss of mental acuity, myopathy, neuropathy, paraesthesia, pigmentation of skin, nails and oral mucosa, pruritus, sweating, taste disturbance, urinary frequency