Action

Inhibits replication of human immunodeficiency virus (HIV) by interfering with the enzyme reverse transcriptase, thereby terminating DNA chain

Availability

Capsules: 15 mg, 20 mg, 30 mg, 40 mg

Powder for oral solution: 1 mg/ml

Indications and dosages

➣ HIV-1 infection

Adults weighing 60 kg (132 lb) or more: 40 mg P.O. q 12 hours

Adults and children weighing less than 60 kg (132 lb): 30 mg P.O. q 12 hours

Children weighing 30 kg (66 lb) or more: 30 mg P.O. q 12 hours

Children 14 days and older who weigh less than 30 kg (66 lb): 1 mg/kg P.O. q 12 hours

Newborns to infants 13 days old: 0.5 mg/kg P.O. q 12 hours

Dosage adjustment

• Renal impairment

• Elderly patients

Contraindications

• Hypersensitivity to drug or its components

Precautions

Use cautiously in:

• advanced HIV infection, bone marrow depression, renal failure, peripheral neuropathy, hepatic dysfunction, hyperlactatemia, lactic acidosis

• concurrent use of hydroxyurea or didanosine (avoid use)

• elderly patients (with renal impairment)

• pregnant or breastfeeding patients.

Administration

• Give with or without food.

• Know that drug is usually given with other antiretrovirals.

Adverse reactions

CNS: headache, insomnia, peripheral neuropathy

GI: nausea, vomiting, diarrhea, abdominal pain, anorexia, pancreatitis

Hematologic: anemia, leukopenia, thrombocytopenia

Hepatic: hepatic steatosis, hepatitis, hepatic failure

Metabolic: increased glucose tolerance, lactic acidosis

Musculoskeletal: myalgia

Skin: rash

Other: body fat redistribution or accumulation, chills, fever, allergic reaction, immune reconstitution syndrome

Interactions

Drug-drug. Chloramphenicol, dapsone, didanosine, ethambutol, hydralazine, hydroxyurea, lithium, phenytoin, vincristine, zalcitabine: increased risk of peripheral neuropathy

Doxorubicin, ribavarin, zidovudine: inhibition of stavudine's absorption and metabolism

Myelosuppressants: increased bone marrow depression

Drug-diagnostic tests. Alanine aminotransferase, amylase, aspartate aminotransferase, bilirubin, gamma-glutamyl transferase, lipase: increased levels

Neutrophils, platelets: decreased counts

Patient monitoring

See Monitor closely for signs and symptoms of lactic acidosis, hyperlactatemia, or pronounced hepatotoxicity (which may include hepatomegaly and steatosis even in the absence of marked transaminase elevations). Consult prescriber about suspending drug if these occur. Consider permanent discontinuation of drug for patients with confirmed lactic acidosis.

• Monitor patient for signs and symptoms of immune reconstitution syndrome.

• Watch for and report onset and worsening of peripheral neuropathy.

See Monitor CBC. Report evidence of bone marrow depression.

• Monitor liver function tests and blood chemistry results.

Patient teaching

• Tell patient he may take with or without food.

See Teach patient to recognize and promptly report signs and symptoms of lactic acidosis (such as fatigue, GI distress, and difficult or rapid breathing), hepatotoxicity, immune reconstitution syndrome, and pancreatitis.

• Instruct patient to report numbness or tingling in arms, legs, hands, or feet.

• Caution female patient not to breastfeed, because she may transmit drug effects and HIV to infant.

• As appropriate, review all other significant and life-threatening adverse reactions and interactions, especially those related to the drugs and tests mentioned above.