Zidovudine

HIV-1, with other antiretrovirals: 300 mg orally twice daily. When oral therapy cannot be used, 1 mg/kg IV at a constant rate over 1 hour every 4 hours, only until oral therapy is feasible.

Dilute the dose from the 20 mL vial in D5W to no greater than 4 mg/mL. The source reports physical/chemical stability 24 hours at room temperature or 48 hours at 2-8 C, but recommends administration within 8 hours at 25 C or 24 hours refrigerated as a microbial-contamination precaution. Inspect for particles/discoloration and discard if present. No rapid infusion, bolus or IM use.

Calculate carefully, check order transcription/dispensing/instructions, and do not exceed the adult dose. Assess ability to swallow capsules; use syrup when capsules are unsuitable.

Weight 4 to under 9 kg: 24 mg/kg/day as 12 mg/kg twice daily or 8 mg/kg three times daily.

Weight 9 to under 30 kg: 18 mg/kg/day as 9 mg/kg twice daily or 6 mg/kg three times daily.

Weight at least 30 kg: 600 mg/day as 300 mg twice daily or 200 mg three times daily.

Alternative BSA dosing: 480 mg/m2/day as 240 mg/m2 twice daily or 160 mg/m2 three times daily. BSA and weight calculations may differ.

The source describes maternal treatment after 14 weeks of pregnancy: 100 mg orally five times daily until labor. During labor/delivery: 2 mg/kg total body weight IV over 1 hour, then 1 mg/kg/hour continuously until cord clamping.

Begin neonatal treatment within 12 hours after birth through age 6 weeks. Its reproduced table gives oral 2 mg/kg every 6 hours (8 mg/kg/day). It mentions IV administration if oral dosing is impossible, but does not reproduce a neonatal IV numeric row; none is inferred.

Toxicity depends on pretreatment marrow reserve, dose and duration. With poor reserve or advanced symptomatic HIV, monitor frequently. Hemoglobin may decline within 2-4 weeks; neutropenia usually appears after 6-8 weeks.

Significant anemia (hemoglobin below 7.5 g/dL or reduction greater than 25%) or neutropenia (granulocytes below 750/mm3 or reduction greater than 50%) may require interruption until marrow recovery. Interruption does not eliminate transfusion needs. Resumption may be considered after recovery, with measures such as recommended-dose epoetin alfa according to erythropoietin levels, indices and tolerability. Consider reducing zidovudine for pronounced anemia with interacting chronic therapy such as fluconazole or valproic acid.

Hepatic dysfunction/cirrhosis: insufficient data for a specific dose adjustment; frequently monitor hematologic toxicity.

Cockcroft-Gault CrCl below 15 mL/min, HD or PD: 100 mg orally every 6-8 hours. The source describes an approximate IV equivalent of 1 mg/kg every 6-8 hours.