Zidovudine

• HIV infection

Zidovudine, a nucleoside reverse transcriptase inhibitor, is indicated in combination with other antiretroviral agents for the treatment of HIV-1 infection.Prevention Of Maternal-Fetal HIV-1 Transmission Zidovudine is indicated for the prevention of maternal-fetal ... Read moreZidovudine, a nucleoside reverse transcriptase inhibitor, is indicated in combination with other antiretroviral agents for the treatment of HIV-1 infection.Prevention Of Maternal-Fetal HIV-1 Transmission Zidovudine is indicated for the prevention of maternal-fetal HIV-1 transmission. The indication is based on a dosing regimen that included 3 components: Antepartum therapy of HIV-1–infected mothers Intrapartum therapy of HIV-1–infected mothers Post-partum therapy of HIV-1–exposed neonate Points to consider prior to initiatingZidovudine in pregnant women for the prevention of maternal-fetal HIV-1 transmission include: In most cases,Zidovudine for prevention of maternal-fetal HIV-1 transmission should be given in combination with other antiretroviral drugs. Prevention of HIV-1 transmission in women who have receivedZidovudine for a prolonged period before pregnancy has not been evaluated. Because the fetus is most susceptible to the potential teratogenic effects of drugs during the first 10 weeks of gestation and the risks of therapy withZidovudine during that period are not fully known, women in the first trimester of pregnancy who do not require immediate initiation of antiretroviral therapy for their own health may consider delaying use; this indication is based on use after 14 weeks’ gestation.

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Hypersensitivity; abnormally low neutrophil counts (<0.75 x 109/L) or Hb levels (<7.5 g/dL or 4.65 mmol/L); newborn infants with hyperbilirubinaemia requiring treatment other than phototherapy, or with increased transaminase levels >5 times the ULN. Lactation. Concomitant use with interferon alfa (with or witho ribavirin) in HIV and hepatitis B or C virus co-infected patients.

Zidovudine is converted intracellularly to zidovudine triphosphate, which inhibits replication of retroviruses, including HIV, by interfering with viral RNA-directed DNA polymerase (reverse transcriptase).

Decreased plasma concentration with rifampicin resulting in partial or total loss of efficacy of zidovudine. Increased risk of anaemia with ribavirin in patients co-infected with HCV. Antagonistic effect with stavudine or doxorubicn. Increased plasma level with probenecid, atovaquone, valproic acid, fluconazole, or methadone. May alter phenytoin blood levels. Increased adverse effect with potentially nephrotoxic or myelosuppressive drugs (e.g. systemic pentamidine, dapsone, pyrimethamine, co-trimoxazole, amphotericin, flucytosine, ganciclovir, interferon, vincristine, vinblastine, doxorubicin). Reduced absorption with clarithromycin.

Dizziness, headache, malaise, myalgia, GI symptoms (e.g. abdominal pain, diarrhoea, nausea, vomiting), anorexia, immune reconstitution syndrome, lipodystrophy, metabolic abnormalities, mitochondrial dysfunction, osteonecrosis; raised liver enzymes, creatine phosphokinase; hyperbilirubinaemia, myalgia, myositis. Rarely, aplastic anaemia, pure red cell aplasia, pancytopenia, thrombocytopenia, rhabdomyolysis, cardiomyopathy, convulsions, pancreatitis.

Symptoms: Vomiting, CNS effects (e.g. fatigue, dizziness, drowsiness, lethargy, confusion), haematologic effects (e.g. anaemia, decreased Hb). Bone marrow hypoplasia, mild ataxia, tonic-clonic seizure and increased serum concentration of AST and ALT may also occur. Management: Supportive and symptomatic treatment. Induce emesis and admin activated charcoal to prevent further absorption of unrecovered drug.

Pregnancy Category C. Either studies in animals have revealed adverse effects on the foetus (teratogenic or embryocidal or other) and there are no controlled studies in women or studies in women and animals are not available. Drugs should be given only if the potential benefit justifies the potential risk to the foetus.

Severe renal and hepatic impairment. Childn. Pregnancy.

Renal Impairment: ESRD maintained on haemodialysis or peritoneal dialysis: 100 mg 6-8 hrly. CrCl <10-15 mL/min: 100 mg 6-8 hrly. Hepatic Impairment: Dose reduction may be needed.