Home Drug Guide Lamivudine

Drug Guide

Generic Name

Lamivudine

Brand Names Epivir, Epivir-HBV

Classification

Therapeutic: Antiviral agent, nucleoside analogue

Pharmacological: Reverse transcriptase inhibitor

FDA Approved Indications

Chronic hepatitis B virus (HBV) infection in adults and children aged ≥3 months
HIV-1 infection in adults and pediatric patients

Mechanism of Action

Lamivudine inhibits viral DNA synthesis by mimicking cytidine and incorporating into viral DNA via reverse transcriptase, leading to chain termination.

Dosage and Administration

Adult: 100 mg once daily for HBV; 300 mg once daily or 150 mg twice daily for HIV

Pediatric: 0.5 mg/kg (up to 300 mg) once daily for HBV in children ≥3 months; 2 mg/kg (up to 300 mg) twice daily for HIV in children ≥3 months

Geriatric: Adjust dose based on renal function; no specific age adjustment but caution advised due to renal impairment

Renal Impairment: Reduce dose based on creatinine clearance; typically 25 mg daily if CrCl 15-29 mL/min, and 15 mg daily if CrCl <15 mL/min

Hepatic Impairment: No specific adjustment necessary for hepatic impairment

Pharmacokinetics

Absorption: Orally well absorbed

Distribution: Widely distributed into body tissues and fluids

Metabolism: Negligible metabolism; primarily excreted unchanged

Excretion: Renal excretion via glomerular filtration and active tubular secretion

Half Life: 5-7 hours

Contraindications

Hypersensitivity to lamivudine or any component

Precautions

Lactic acidosis and severe hepatomegaly with steatosis reported with nucleoside analogues; use with caution in patients with renal impairment; monitor renal function regularly

Adverse Reactions - Common

Headache (Common)
Nausea (Common)
Fatigue (Common)

Adverse Reactions - Serious

Lactic acidosis (Rare)
Acute exacerbation of hepatitis B upon discontinuation (Rare)

Drug-Drug Interactions

Emtricitabine (may increase risk of lactic acidosis)

Drug-Food Interactions

N/A

Drug-Herb Interactions

N/A

Nursing Implications

Assessment: Monitor renal function, serum lactate, and hepatic function

Diagnoses:

Risk for impaired renal function

Implementation: Administer as directed; monitor for signs of lactic acidosis or hepatomegaly

Evaluation: Assess viral load and liver function tests periodically to evaluate effectiveness

Patient/Family Teaching

Take medication exactly as prescribed
Report symptoms of lactic acidosis (mġus, muscle pain, difficulty breathing) or hepatomegaly
Maintain regular follow-up appointments

Special Considerations

Black Box Warnings:

Severe acute exacerbations of hepatitis B may occur when used for hepatitis B patients and discontinued

Genetic Factors: None specified

Lab Test Interference: May cause false-positive result for serum hepatitis B surface antigen (HBsAg)

Overdose Management

Signs/Symptoms: Nausea, vomiting, somnolence, dizziness, coma, and lactic acidosis

Treatment: Supportive care; hemodialysis may be considered if significant overdose occurs, especially if renal function is impaired

Storage and Handling

Storage: Store at room temperature 25°C (77°F); keep container tightly closed

Stability: Stable for up to 1 year when stored properly