Epivir HBV (lamivudine) is a nucleoside reverse transcriptase inhibitor specifically indicated for the treatment of chronic hepatitis B virus (HBV) infection in adults and pediatric patients. This antiviral medication works by inhibiting the reverse transcriptase enzyme, thereby reducing viral replication and liver inflammation. Clinical studies have demonstrated its efficacy in achieving undetectable HBV DNA levels, normalizing ALT levels, and inducing hepatitis B e antigen (HBeAg) seroconversion. Proper patient selection and adherence to treatment guidelines are essential for optimizing therapeutic outcomes and minimizing resistance development.

Features

• Active ingredient: Lamivudine 100 mg
• Formulation: Film-coated tablets and oral solution (5 mg/mL)
• Mechanism: Nucleoside reverse transcriptase inhibitor
• Bioavailability: Approximately 86% for tablet formulation
• Half-life: 5–7 hours in adults with normal renal function
• Metabolism: Minimal hepatic metabolism; primarily renal excretion
• FDA-approved for treatment of chronic hepatitis B infection

Benefits

• Achieves significant reduction in HBV DNA viral load
• Normalizes serum alanine aminotransferase (ALT) levels
• Promotes histological improvement in liver inflammation
• Induces HBeAg seroconversion in appropriate patients
• Well-tolerated profile with established safety data
• Available in pediatric formulation for children aged 2–17 years

Common use

Epivir HBV is primarily prescribed for the management of chronic hepatitis B infection in patients with evidence of viral replication and active liver inflammation. It is indicated for both HBeAg-positive and HBeAg-negative chronic hepatitis B. Treatment is typically initiated in patients with elevated ALT levels (≥2 times upper limit of normal) and detectable HBV DNA. The medication may be used as monotherapy or in combination with other antivirals based on treatment history and resistance profile. Regular monitoring of viral load, liver function tests, and serological markers is essential throughout therapy.

Dosage and direction

The recommended adult dosage is 100 mg orally once daily, with or without food. For pediatric patients aged 2–17 years, the dosage is based on body weight: 3 mg/kg once daily up to a maximum of 100 mg daily. Renal impairment requires dosage adjustment: for creatinine clearance 30–49 mL/min, administer 100 mg first dose then 50 mg daily; for 15–29 mL/min, 100 mg first dose then 25 mg daily; for 5–14 mL/min, 35 mg first dose then 15 mg daily; for <5 mL/min, 35 mg first dose then 10 mg daily. Treatment duration should be individualized based on virological response, serological status, and treatment guidelines.

Precautions

Regular monitoring of HBV DNA levels is crucial to detect virological breakthrough, which may indicate emerging resistance. Liver function tests should be performed every 3–6 months during therapy. Patients with advanced liver disease or cirrhosis require close monitoring for hepatic decompensation. Lactic acidosis and severe hepatomegaly with steatosis, including fatal cases, have been reported with nucleoside analogues. Use with caution in patients with risk factors for liver disease. Exacerbations of hepatitis may occur upon discontinuation of therapy; monitor patients for several months after stopping treatment.

Contraindications

Epivir HBV is contraindicated in patients with known hypersensitivity to lamivudine or any component of the formulation. Concomitant use with other medications containing lamivudine or emtricitabine is contraindicated due to potential additive effects and toxicity. The medication should not be used as monotherapy in HIV-coinfected patients unless combined with a fully suppressive antiretroviral regimen, due to risk of HIV resistance development.

Possible side effect

Common adverse reactions (≥10%) include headache, fatigue, nausea, diarrhea, and cough. Less frequent side effects include neutropenia, anemia, thrombocytopenia, elevated liver enzymes, and pancreatitis. Rare but serious adverse effects include lactic acidosis, severe hepatomegaly with steatosis, and acute exacerbations of hepatitis upon discontinuation. Allergic reactions including Stevens-Johnson syndrome and anaphylaxis have been reported. Peripheral neuropathy and muscle disorders may occur, particularly in pediatric patients.

Drug interaction

Concomitant administration with trimethoprim/sulfamethoxazole increases lamivudine exposure by approximately 40%. Zalcitabine may inhibit the intracellular phosphorylation of lamivudine. Drugs that reduce renal function or compete for active renal tubular secretion may increase lamivudine concentrations. No clinically significant interactions have been observed with interferon alfa, adefovir, or most commonly prescribed medications. However, caution is advised when coadministering with other nephrotoxic agents.

Missed dose

If a dose is missed, patients should take it as soon as remembered, unless it is almost time for the next scheduled dose. In that case, the missed dose should be skipped and the regular dosing schedule resumed. Patients should not double the dose to make up for a missed dose. Consistent adherence to the prescribed dosing schedule is critical for maintaining viral suppression and preventing resistance development.

Overdose

There is limited experience with lamivudine overdose. Reported cases involved doses up to 6 grams daily with no specific symptoms. Hemodialysis removes approximately 70% of lamivudine over 4 hours, with a clearance of 50 mL/min. In case of overdose, standard supportive measures should be implemented, and hemodialysis may be considered if appropriate. Monitor for signs of lactic acidosis and hepatic steatosis, even with single large doses.

Storage

Store tablets and oral solution at controlled room temperature, 20–25°C (68–77°F). Keep the container tightly closed and protect from moisture. The oral solution should be stored in the original container and used within the expiration date. Do not freeze. Keep out of reach of children and pets. Discard any unused medication properly according to local regulations.

Disclaimer

This information is provided for educational purposes only and does not constitute medical advice. Treatment decisions should be made by qualified healthcare professionals based on individual patient characteristics. The prescribing physician should be consulted for complete information regarding indications, dosage, administration, and monitoring requirements. Patients should not alter their treatment regimen without medical supervision.

Reviews

Clinical trials have demonstrated that 52–56% of HBeAg-positive patients achieved HBV DNA suppression to below detection limits after one year of therapy. Histological improvement was observed in 49–56% of patients compared to 23–25% of placebo recipients. HBeAg seroconversion rates range from 16–18% after one year, increasing with longer treatment duration. Resistance development remains a concern, with genotypic resistance observed in 24% of patients after one year and 70% after four years of monotherapy. Real-world evidence supports its efficacy in appropriate patient populations when used according to treatment guidelines.