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Pharmacologic class: Nucleoside reverse transcriptase inhibitor
Therapeutic class: Antiretroviral
Pregnancy risk category C
FDA Box Warning
• Drug has been linked to hematologic toxicity (including neutropenia and severe anemia), particularly in patients with advanced human immunodeficiency virus (HIV) infection.
• Prolonged use is associated with symptomatic myopathy.
• Lactic acidosis and severe hepatomegaly with steatosis (including fatal cases) have occurred with use of nucleoside analogs alone or in combination, including zidovudine and other antiretrovirals.
After conversion to its active metabolite, inhibits activity of HIV reverse transcriptase and terminates viral DNA growth
Capsules: 100 mg
Injection: 10 mg/ml in 20-ml vial
Syrup: 50 mg/5 ml
Tablets: 300 mg
Indications and dosages
➣ HIV-1 infection
Adults and children older than age 12: 600 mg P.O. total daily dosage divided into either b.i.d. or t.i.d. dosing; or 1 mg/kg I.V. five to six times daily; in combination with other antiretrovirals
Children ages 4 weeks to younger than 18 years weighing 30 kg (66 lb) or more: 600 mg P.O. total daily dosage divided into either b.i.d. or t.i.d. dosing; or 480 mg/m2 total daily dosage divided into either b.i.d. or t.i.d. dosing. Don't exceed recommended adult dosage.
Children ages 4 weeks to younger than 18 years weighing 9 kg (20 lb) to less than 30 kg (66 lb): 18 mg/kg/day total daily dosage divided into either b.i.d. or t.i.d. dosing; or 480 mg/m2 total daily dosage divided into either b.i.d. or t.i.d. dosing. Don't exceed recommended adult dosage.
Children ages 4 weeks to younger than 18 years weighing 4 kg (9 lb) to less than 9 kg (20 lb): 24 mg/kg/day total daily dosage divided into either b.i.d. or t.i.d. dosing; or 480 mg/m2 total daily dosage divided into either b.i.d. or t.i.d. dosing. Don't exceed recommended adult dosage.
➣ To prevent maternal-fetal HIV transmission
Pregnant women (more than 14 weeks of pregnancy): 500 mg P.O. daily in divided doses (usually as five 100-mg doses) until labor begins; then 2 mg/kg I.V. over 1 hour followed by a continuous infusion of 1 mg/kg/hour until umbilical cord is clamped
Neonates: 2 mg/kg P.O. q 6 hours starting within 12 hours of delivery and continuing for 6 weeks. For neonates unable to receive oral dosing, 1.5 mg/kg by I.V. infusion over 30 minutes q 6 hours
• End-stage renal disease in patients maintained on hemodialysis or peritoneal dialysis
• Hematologic toxicity
• Concurrent use of drugs (such as fluconazole or valproic acid) in patients experiencing pronounced anemia
• Occupational exposure to HIV
• Patients who have had potentially life-threatening allergic reactions (such as anaphylaxis, Stevens-Johnson syndrome) to drug or its components
Use cautiously in:
• renal or hepatic impairment, known risk factors for liver disease, decreased bone marrow reserve, hemoglobin less than 9.5 g/dl, granulocyte count less than 1,000 cells/mm3
• concurrent use of Combivir or Trizivir (zidovudine-containing products) or interferon- and ribavirin-based regimens
• pregnant or breastfeeding patients.
☞ For I.V. use, remove dose from vial and add to I.V. solution containing dextrose 5% in water, to yield a final concentration no higher than 4 mg/ml. Infuse over 1 hour. Avoid rapid infusion or bolus injection. Don't give by I.M. route.
• In adults, give by I.V. route only until patient can tolerate oral dose.
• If a child is unable to reliably swallow a capsule or tablet, give syrup formulation.
CNS: headache, paresthesia, malaise, insomnia, dizziness, drowsiness, asthenia, seizures
GI: nausea, vomiting, constipation, abdominal pain, dyspepsia, anorexia, pancreatitis
Hematologic: severe anemia (necessitating transfusions), agranulocytopenia, severe bone marrow depression
Hepatic: severe hepatomegaly with steatosis
Metabolic: lactic acidosis
Musculoskeletal: myalgia, back pain, myopathy
Skin: diaphoresis, rash, altered nail pigmentation
Other: abnormal taste, fever, immune reconstitution syndrome
Drug-drug. Acetaminophen, aspirin, indomethacin: increased risk of zidovudine toxicity
Amphotericin B, dapsone, flucytosine, pentamidine: increased risk of nephrotoxicity and bone marrow depression
Cyclosporine: extreme drowsiness, lethargy
Cytotoxic drugs, myelosuppressants, nephrotoxic drugs (such as ganciclovir, interferon alfa): increased risk of hematologic toxicity
Fluconazole, methadone, probenecid, valproic acid: increased zidovudine blood level, greater risk of toxicity
Ribavirin: antagonism of zidovudine's antiviral activity
Drug-diagnostic tests. Granulocytes, hemoglobin, platelets: decreased levels
Drug-herbs. St. John's wort: decreased zidovudine efficacy
• Monitor neurologic status, especially for signs and symptoms of impending seizure.
☞ Periodically assess CBC and kidney and liver function tests. Be aware that drug can cause hepatotoxicity.
☞ Watch for signs and symptoms of pancreatitis, immune reconstitution syndrome, and lactic acidosis.
• Tell patient he may take with or without food.
• Instruct patient to take capsules with at least 4 oz of fluid and to stay upright after taking.
• Explain therapy to patient. Emphasize that drug doesn't cure HIV infection.
• Urge patient to take drug exactly as prescribed.
☞ Teach patient to recognize and immediately report signs and symptoms of serious side effects, such as seizures.
• Stress importance of follow-up laboratory testing.
• Advise female of childbearing age to use effective contraception.
• Inform pregnant patient that drug reduces risk of, but may not prevent, HIV transmission to neonate.
• As appropriate, review all other significant and life-threatening adverse reactions and interactions, especially those related to the drugs, tests, and herbs mentioned above.
AZTA nucleoside analogue used with other anti-HIV agents to manage AIDS and HIV infection.
Long-term AZT use is associated with muscle loss, nausea, anaemia, myelosuppression, oral ulcers, bone marrow damage and headache.