Detailed Drug Information:

DRUG CLASS AND MECHANISM: Lamivudine is an oral medication that is used for the treatment of infections with the human immunodeficiency (HIV) and hepatitis B viruses. It is in a class of drugs called reverse transcriptase inhibitors which also includes zalcitabine (Hivid), zidovudine (Retrovir), didanosine (Videx), and stavudine (Zerit). During infection with HIV, the HIV virus multiplies within the body's cells. The viruses then are released from the cells and spread throughout the body where they infect other cells. In this manner, HIV infection spreads to new, uninfected cells that the body is continually producing, and HIV infection is perpetuated. When producing new viruses, the HIV virus must manufacture new DNA for each virus. Reverse transcriptase is thevirus' enzyme that forms this new DNA. Lamivudine first is converted within the body to its active form, lamivudine triphosphate. This active form is similar to a chemical, deoxycytidine triphosphate, that is used by reverse transcriptase to make new DNA. The reverse transcriptase uses lamivudine triphosphate instead of deoxycytidine triphosphate, and the lamivudine triphosphate interferes with the reverse transcriptase. Lamivudine does not kill existing HIV virus, and it is not a cure for HIV. Lamivudine was approved by the FDA in 1995.

PREPARATIONS: Tablets: 150 mg; oral solution 10 mg/ml

STORAGE: Store tablets and solution at room temperature, 15-30°C (59-86°F).

PRESCRIBED FOR: Lamivudine is used for the treatment of HIV infection, prevention of HIV in those accidentally exposed to HIV, and the treatment of the hepatitis B infection.

DOSING: For the treatment of HIV infection the recommended dose for adults is 150 mg twice daily for those weighing 50 kg or more and 2 mg/kg twice daily if less than 50 kg.

Children (12 to 16 years old) weighing 50 kg or more should receive 150 mg twice daily.

Children ( 3 months to 12 years old) should be treated with 4 mg/kg twice daily up to a maximum dose of 300 mg daily.

For postexposure prevention of HIV infection, 150 mg twice daily of lamivudine is administered in conjunction with 600 mg daily of zidovudine(Retrovir) for 28 days.

Hepatitis B is treated with 100 mg twice daily.

Lamivudine may be administered without regard to meals.

DRUG INTERACTIONS: Trimethoprim/sulfamethoxazole(Bactrim) increases the concentration of lamivudine in the body.

PREGNANCY: Use of lamivudine during pregnancy has not been adequately evaluated.

NURSING MOTHERS: It is not known whether lamivudine is secreted in breast milk. HIV infected mothers should not breast feed because of the potential risk of transmitting HIV to an infant that is not infected.

SIDE EFFECTS: The most severe side effects are pancreatitis, liver failure and metabolic disturbance (lactic acidosis). Lamivudine also causes a decrease in blood cells, muscle pain and weakness, and nerve damage in the extremities (peripheral neuropathy). Symptoms of peripheral neuropathy are tingling, numbness and pain in the feet or hands. Other side effects are fever, abdominal pain, weight loss, nausea, vomiting, diarrhea, hair loss and difficulty sleeping.