| ZIDOVUDINE (formerly AZIDOTHYMIDINE, AZT)
Classifications: antiviral; nucleoside reverse transcriptase inhbitor; Therapeutic: antiviral; nrti
Pregnancy Category: C
300 mg tablets; 100 mg capsules; 50 mg/5 mL syrup; 10 mg/mL injection
Appears to act by being incorporated into growing DNA chains by viral reverse transcriptase, thereby terminating viral replication.
Zidovudine has antiviral action against HIV, LAV (lymphadenopathy-associated virus), and ARV (AIDS-associated retrovirus).
Patients who are HIV positive and have a CD4 count ≤500/mm3, asymptomatic HIV infection, early and late symptomatic HIV disease, prevention of perinatal transfer of HIV during pregnancy.
Pediatric patients, postexposure chemoprophylaxis.
Life-threatening allergic reactions to any of the components of the drug; lactic acidosis; pregnancy (category C), lactation.
Impaired renal or hepatic function, alcoholism; anemia; chemotherapy; radiation therapy; bone marrow depression.
Route & Dosage
|Symptomatic HIV Infection
Adult: PO 300 mg b.i.d. OR 200 mg t.i.d. IV 12 mg/kg q4h (1200 mg/d)
Child (3 mo13 y): PO 160 mg/m2 q8h IV 120 mg/m2 q6h
Prevention of Maternal-Fetal Transmission
Neonate: PO Full term: 2 mg/kg q6h for 6 wk beginning within 12 h after birth; 3035 wk gestation: 2 mg/kg q12h for 2 wk, then q8h for 4 wk; <30 wk gestation: 2 mg/kg q12h for 4 wk, then q8h for 2 wk IV Full term: 1.5 mg/kg q6h x 6 wk
Maternal: PO 100 mg 5 times daily OR 300 mg b.i.d. from 14 wk gestation until delivery IV During labor, 2 mg/kg loading dose, then 1 mg/kg/h
- Do not expose capsules and syrup to light during drug preparation.
PREPARE: Intermittent: Withdraw required dose from vial and dilute with D5W to a concentration not to exceed 4 mg/mL.
ADMINISTER: Intermittent for HIV infection: Give calculated dose at a constant rate over 60 min; avoid rapid infusion. IV Infusions for Prevention of Maternal-Fetal Transmission: Give maternal loading dose over 1 h, then continuous infusion at 1 mg/kg/h. Intermittent Infusion for Prevention of Maternal Transmission of HIV to Neonate: Give calculated dose at a constant rate over 30 min.
INCOMPATIBILITIES Solution/additive: Meropenem. Y-site: Meropenem.
- Store at 15°25° C (59°77° F) and protect from light. Store diluted IV solutions refrigerated
for 24 h.
Adverse Effects (≥1%) Body as a Whole: Fever,
myopathy. CNS: Headache, insomnia
, dizziness, paresthesias, mild confusion, anxiety, restlessness, agitation. GI: Nausea,
diarrhea, vomiting, anorexia,
GI pain. Hematologic: Bone marrow depression, granulocytopenia, anemia. Respiratory: Cough, wheezing. Skin: Rash,
InteractionsDrug: Acetaminophen ganciclovir, interferon-alfa
may enhance bone marrow
suppression; atovaquone, amphotericin B, aspirin, dapsone, doxorubicin, fluconazole, flucytosine, indomethacin, interferon alfa, methadone, pentamidine, vincristine, valproic acid
may increase risk of AZT toxicity; probenecid
will decrease AZT elimination, resulting in increased serum levels and thus toxicity. Nelfinavir, rifampin, ritonavir
may decrease zidovudine (AZT) concentrations; other antiretroviral agents
may cause lactic acidosis and severe hepatomegaly with steatosis; stavudine, doxorubicin
may antagonize AZT effects.
Readily from GI tract; 6070% reaches systemic circulation (first-pass metabolism). Peak:
0.51.5 h. Distribution:
Crosses bloodbrain barrier and placenta. Metabolism:
In liver. Elimination:
6395% in urine. Half-Life:
Assessment & Drug Effects
- Evaluate patient at least weekly during the first month of therapy.
- Lab tests: Baseline and frequent (at least q2wk) blood counts, CD4 (T4) lymphocyte count, Hgb, and granulocyte count to detect hematologic toxicity.
- Myelosuppression results in anemia, which commonly occurs after 46 wk of therapy, and granulocytopenia in 68
wk. Frequently, both respond to dosage adjustment. Significant anemia (Hgb <7.5 g/dL or reduction >25% of baseline value),
or granulocyte count <750/mm3 (or reduction >50% of baseline) may require temporary interruption of therapy and transfusions.
- Monitor for common adverse effects, especially severe headache, nausea, insomnia, and myalgia.
Patient & Family Education
- Contact physician promptly if health status worsens or any unusual symptoms develop.
- Understand that this drug is not a cure for HIV infection; you will continue to be at risk for opportunistic infections.
- Do not share drug with others; take drug exactly as prescribed.
- Drug does NOT reduce the risk of transmission of HIV infection through body fluids.