Last Updated June 10, 2016
Nucleoside reverse transcriptase inhibitor antiretroviral
Indication: treatment of HIV infection in combination with other antiretrovirals, reduction of perinatal transmission of HIV, postexposure prophylaxis in combination with other antiretrovirals.
Mechanism of action*: a thymidine analogue that is phosphorylated intracellularly to zidovudine 5’-triphosphate which interferes with HIV viral RNA–dependent DNA polymerase inhibiting viral replication.
Pharmacokinetics: metabolized in the liver via glucuronidation to inactive metabolite GZDV; 65% to 75% of GZDV is excreted in the urine. Half-life: serum = 1.1 hours; intracellular = 7 hours. Good cerebrospinal fluid penetration.
Adult Dose for Treatment of HIV:
Adult Dose for Prevention of Mother-to-Child Transmission:
Take without regard to meals.*
Use in Renal or Hepatic Insufficiency: Decrease dose by 50% or double dosage interval if significant liver disease.†
Dosage for patients with chronic kidney disease or end-stage renal disease‡:
Use in Pregnancy and Breastfeeding: Category C. Excreted in breast milk.*
Use in Children:
Prevention of mother-to-child HIV transmission (in neonates): Note: start as soon as possible after birth, preferably within 6-12 hours of delivery. Continue dose from birth through 6 weeks of age.
Intravenous (infants unable to receive oral dosing):
Paediatric dose (3 months to 12 years): 180 mg/m2 twice daily orally (maximum: 800 mg/day) (suspension may be given with food).
US Prescribing Information Boxed Warning*: haematologic toxicity including neutropenia and severe anaemia have been associated with zidovudine.
Oesophageal ulceration may occur unless adequate fluid is ingested with oral doses.
US Prescribing Information Boxed Warning*: symptomatic myopathy associated with prolonged use of zidovudine.
US Prescribing Information Boxed Warning*: lactic acidosis/hepatomegaly with steatosis has been reported with nucleoside analogues with fatal cases reported. Use in caution with patients with risk factors for liver disease and suspend treatment if a patient develops signs and symptoms.
Precautions: ganciclovir (potential for increased haematologic toxicity), ribavirin (inhibits phosphorylation of zidovudine and increased haematologic toxicity),* myelosuppressive agents (increased risk of bone marrow suppression), probenecid (delayed excretion), valproate (zidovudine levels significantly increased).
See above for pregnancy and lactation.
Bone marrow suppression, nausea, vomiting, headache, insomnia, nail pigmentation, fat redistribution, myopathy.
*Information from US prescribing information.
†Recommendation from Southern African HIV Clinician Society Guidelines.
‡Recommendation from South African Renal Society, 2008.