Zidovir

Description

Zidovudine is a thymidine analogue. In the body, it’s converted into its active form, zidovudine triphosphate, which then interferes with the DNA synthesis of retroviruses by inhibiting DNA replication. Specifically, it targets and inhibits the crucial enzyme reverse transcriptase. It’s important to note that zidovudine inhibits human DNA polymerase at concentrations much higher (100 times) than those needed to inhibit viral reverse transcriptase.

Dosage Information

Zidovir can be taken with or without food.

• Adults with HIV Infection:
  • Oral: 300 mg every 12 hours OR 200 mg every 8 hours (total 600 mg/day).
  • Intravenous (IV): 1 mg/kg/dose 5-6 times per day.
• Maternal Dosing to Prevent Fetal HIV Transmission:
  • FDA-Approved Regimen:
    • 100 mg orally five times a day until labor starts, combined with other antiretroviral (ART) agents.
    • During labor and delivery: 2 mg/kg IV over 1 hour, followed by a continuous IV infusion of 1 mg/kg/hour until umbilical cord clamping.
  • NIH Perinatal Guidelines:
    • Recommended during labor and delivery for women with HIV RNA levels >400 copies/mL, or for those who haven’t received antepartum ART.
    • 2 mg/kg IV loading dose infused over 1 hour, then 1 mg/kg/hour until umbilical cord clamping.
    • Women who have received antepartum ART and have HIV RNA levels <400 copies/mL typically do not require IV zidovudine.
• Children with HIV Infection (Treatment):
  • Ages 4 weeks to 18 years:
    • Oral: 240 mg/m² every 12 hours OR 160 mg/m² every 8 hours. Alternatively, mg/kg dosing:
      • 4 to <9 kg: 12 mg/kg orally every 12 hours OR 8 mg/kg orally three times a day.

      • 9 to <30 kg: 9 mg/kg orally every 12 hours OR 6 mg/kg orally three times a day.

      • 30 kg: 300 mg orally every 12 hours OR 200 mg orally three times a day.

    • IV Intermittent Infusion: 120 mg/m² IV every 6 hours.
    • IV Continuous Infusion: 20 mg/m²/hour IV.
• Children for HIV Perinatal Transmission Prevention (Mother-to-Child):
  • Recommended for all HIV-exposed infants.
  • FDA-Approved Regimen: 2 mg/kg orally every 6 hours OR 1.5 mg/kg IV every 6 hours.
  • NIH Perinatal Guidelines:
    • <30 weeks’ gestation: 2 mg/kg orally or 1.5 mg/kg IV twice daily; after 4 weeks of age, increase to 3 mg/kg orally or 2.3 mg/kg IV every 12 hours.

    • 30 to <35 weeks’ gestation: 2 mg/kg orally twice daily; after 15 days of age, increase to 3 mg/kg orally or 2.3 mg/kg IV every 12 hours.

    • 35 weeks’ gestation: 4 mg/kg orally or 3 mg/kg IV twice daily for 6 weeks.

• Hepatic Impairment: A reduction in daily dose or an extended dosing interval may be necessary.