lamivudine

lamivudine /la·miv·u·dine/ (lah-miv´u-den) a nucleoside analogue that inhibits reverse transcriptase, used as an antiviral agent in the treatment of chronic hepatitis B and, in combination with zidovudine, the treatment of HIV infection and AIDS.

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la·miv·u·dine (l-mvy-dn)

n.

An antiretroviral drug that is a nucleoside analog and inhibits replication of HIV.

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lamivudine (3TC),

n brand name: Epivir;
drug class: antiviral, nucleoside analog;
action: inhibition of HIV reverse transcriptase; also inhibits RNA- and DNA-dependent DNA polymerase;
use: in combination with zidovudine for the treatment of HIV infection.

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lamivudine

Epivir, Epivir-HBV, 3TC (CA), Zeffix (UK)

Pharmacologic class: Nucleoside reverse transcriptase inhibitor

Therapeutic class: Antiretroviral

Pregnancy risk category C

FDA Boxed Warning

• Lactic acidosis and severe hepatomegaly with steatosis (including fatal cases) have occurred when drug was used alone or in combination with other nucleoside analogues.
• Epivir tablets and oral solution (used to treat human immunodeficiency virus [HIV] infection) contain higher dose of active ingredient (lamivudine) than Epivir-HBV tablets and oral solution (used to treat chronic hepatitis B). Patients with HIV should receive only dosing forms appropriate for HIV treatment.
• After Epivir discontinuation, severe acute hepatitis B exacerbations have occurred in patients co-infected with hepatitis B virus (HBV) and HIV. Monitor hepatic function closely for at least several months in these patients. If appropriate, begin anti-hepatitis B therapy.

Action

Inhibits HIV reverse transcription by viral DNA chain termination. Impedes RNA- and DNA-dependent DNA polymerase activities.

Availability

Oral solution: 5 mg/ml and 10 mg/ml in 240-ml bottles

Tablets: 100 mg, 150 mg, 300 mg

⊘Indications and dosages

➣ HIV infection (given with other antiretrovirals)

Adults and children older than age 16: 150 mg P.O. b.i.d. or 300 mg P.O. daily

Children ages 3 months to 16 years: 4 mg/kg P.O. b.i.d. to a maximum of 150 mg P.O. b.i.d.

➣ Chronic HBV

Adults: 100 mg (Epivir-HBV) P.O. once daily

Children ages 2 to 17: 3 mg/kg (Epivir-HBV) P.O. once daily, to a maximum of 100 mg P.O. daily

Dosage adjustment

• Renal impairment

Contraindications

• Hypersensitivity to drug or its components

Precautions

Use cautiously in:
• impaired renal function, history of hepatic disease, obesity, granulocyte count below 1,000/mm³
• long-term therapy
• elderly patients
• women (especially if pregnant)
• children.

Administration

• Give with or without food.
☞ Be aware that Epivir contains 150 mg lamivudine and Epivir-HBV contains 100 mg lamivudine. Strengths are not interchangeable.
☞ Know that when given to patients with unrecognized or untreated HIV, Epivir-HBV is likely to cause rapid emergence of HIV resistance.

Route	Onset	Peak	Duration
P.O.	Unknown	0.9 hr	12 hr

Adverse reactions

CNS: fatigue, headache, insomnia, malaise, asthenia, depression, dizziness, paresthesia, peripheral neuropathy, seizures

GI: nausea, vomiting, diarrhea, anorexia, abdominal discomfort, dyspepsia, splenomegaly, pancreatitis

Hematologic: anemia, neutropenia

Hepatic: hepatomegaly with steatosis

Metabolic: hyperglycemia, lactic acidosis

Musculoskeletal: muscle, joint, or bone pain; muscle weakness; myalgia; rhabdomyolysis

Respiratory: cough, abnormal breath sounds, wheezing

Skin: alopecia, rash, urticaria, erythema multiforme, Stevens-Johnson syndrome

Other: lymphadenopathy, body fat redistribution, hypersensitivity reactions including anaphylaxis

Interactions

Drug-drug. Co-trimoxazole: increased lamivudine blood level

Zalcitabine: interference with effects of both drugs

Drug-diagnostic tests. Alanine aminotransferase, alkaline phosphatase, aspartate aminotransferase, bilirubin, creatine kinase, liver function tests: increased levels

Hemoglobin, hematocrit, neutrophils: decreased levels

Patient monitoring

• Check vital signs regularly.
• Monitor CBC and platelet count frequently. Watch for evidence of bone marrow toxicity.
• Monitor blood glucose level and kidney and liver function test results.
• Assess neurologic and mental status. Report signs or symptoms of depression.
• Closely monitor obese patients, women, and patients with a history of hepatic disease; they're at increased risk for lactic acidosis and severe hepatomegaly with steatosis.
• Monitor HIV patients for co-infection with HBV (which may recur when drug is withdrawn).

Patient teaching

• Tell patient he may take with or without food.
• Advise patient to minimize GI upset by eating small, frequent servings of healthy food and drinking plenty of fluids.
• Tell HIV patient that drug doesn't cure virus or prevent its transmission and that opportunistic infections may occur. Advise him to take appropriate precautions during sex.
• Caution patient to avoid driving and other hazardous activities until he knows how drug affects concentration and alertness.
• Caution HIV patient not to breastfeed, because of risk of passing infection 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.