zidovudine: prescribing and clinical use
Focused clinical detail for use alongside current product information, local policy and patient-specific assessment.
zidovudine: clinical details
Prescribing considerations
- Initiation and supervision should involve clinicians experienced in HIV treatment.
- Use as part of combination antiretroviral therapy; avoid monotherapy where possible.
- Review marrow reserve, renal and hepatic function, hepatitis coinfection, interacting medicines and previous zidovudine-related anaemia.
- Reassess treatment if clinically significant cytopenias, mitochondrial toxicity or lipoatrophy develops.
Contraindications and cautions
- Hypersensitivity to zidovudine or a formulation excipient.
- Neutrophil count below 0.75 × 10^9/L or haemoglobin below 7.5 g/dL.
- In newborn infants, hyperbilirubinaemia requiring treatment beyond phototherapy or transaminases over five times the upper limit of normal.
- The oral solution contains maltitol and is unsuitable in hereditary fructose intolerance.
Monitoring
- Full blood count, particularly haemoglobin, neutrophils and leucocytes.
- Liver function, especially with pre-existing liver disease or hepatitis coinfection.
- Renal function where impairment or nephrotoxic combinations are relevant.
- Clinical evidence of lactic acidosis, pancreatitis, myopathy, lipoatrophy and immune reactivation.
- Antiviral response and resistance within the complete antiretroviral regimen.
Clinical pharmacology
A thymidine analogue activated inside cells by phosphorylation. Its triphosphate metabolite inhibits HIV reverse transcriptase and causes viral DNA chain termination. Metabolism is mainly hepatic glucuronidation, with renal elimination of zidovudine and its inactive metabolite.
Formulation and product differences
- Capsules are swallowed whole; oral solution is available where capsules are unsuitable.
- The sugar-free, strawberry-flavoured oral solution includes a dosing syringe and contains maltitol, sodium benzoate and propylene glycol, with specific neonatal cautions.
- The preservative-free intravenous concentrate requires aseptic dilution and slow intravenous infusion. It must not be administered into muscle.
zidovudine preparations and strengths
Capsule
Route: Oral
Strengths: 100 mg, 250 mg
Oral solution
Route: Oral
Strengths: 100 mg/10 mL
zidovudine interactions
Check prescribed, non-prescription and herbal products with the HIV team or pharmacist. Important examples include:
Rifampicin
Can substantially reduce zidovudine exposure and potentially reduce effectiveness; concomitant use should be avoided.
Stavudine
Has an antagonistic antiviral interaction with zidovudine, so concomitant use should be avoided.
Ribavirin
Increases the risk of anaemia; concomitant use is not recommended.
Probenecid
Raises zidovudine exposure and requires closer monitoring for blood toxicity.
Sources
These sources were used to prepare and review this medicine page.
Prepared and reviewed by the iatroX editorial team.