Lamivudine
Lamivudine is an antiviral agent, a synthetic nucleoside analogue, indicated in combination with other antiretroviral agents for the treatment of HIV-1 infection. For a plain-language summary written for patients, see MedlinePlus’s drug information on lamivudine.
Epivir Hbv
Chronic Hepatitis B Virus Infection
100mg · 150mg
Developed to mitigate active hepatitis B replication to support liver cell safety and target viral reverse transcription.
Key points
- Once inside a cell, lamivudine is converted to its active form, a metabolite called lamivudine triphosphate (3TC-TP), which is what acts against the virus.
- Taken by mouth, lamivudine is well absorbed: one study found an absolute bioavailability of around 86% for a 150 mg tablet in adults.
- Lamivudine is not significantly broken down by the liver’s cytochrome P450 enzymes.
- Lamivudine carries a boxed warning: in people also living with hepatitis B, stopping lamivudine can cause the hepatitis to flare up severely, so any change in treatment needs medical supervision.
How it works
Lamivudine is a synthetic nucleoside analogue. Once inside a cell, it is converted into its active form, lamivudine triphosphate (3TC-TP). 3TC-TP works by inhibiting the HIV-1 enzyme reverse transcriptase, stopping the virus from completing new copies of its own DNA, a process known as chain termination.
Safety specific to Lamivudine
Lamivudine’s US prescribing information carries a boxed warning covering three risks.
Lactic acidosis and severe hepatomegaly with steatosis, including fatal cases, have been reported with the use of nucleoside analogues and other antiretrovirals; lamivudine should be discontinued if clinical or laboratory findings suggestive of lactic acidosis or pronounced hepatotoxicity occur. This has been seen more often in women, and obesity and prolonged exposure to nucleoside medicines may be risk factors.
Severe acute exacerbations of hepatitis B have been reported in patients co-infected with hepatitis B virus (HBV) and HIV-1 who have discontinued lamivudine. Anyone stopping lamivudine in this situation needs hepatic function monitored closely, with clinical and laboratory follow-up for at least several months, and may need to start treatment for hepatitis B if appropriate.
Lamivudine is made in different strengths for different uses: lamivudine tablets used to treat HIV-1 infection contain a higher dose of lamivudine than lamivudine-HBV tablets used to treat chronic HBV infection. People with HIV-1 infection should receive only the dosage form appropriate for HIV-1.
Lamivudine has also been linked to pancreatitis. It should be used with caution in children who have had prior antiretroviral nucleoside exposure, a history of pancreatitis, or other significant risk factors, and treatment should be stopped immediately if signs, symptoms or laboratory findings suggestive of pancreatitis occur.
Starting combination antiretroviral therapy, including lamivudine, has been reported to trigger immune reconstitution syndrome: as the immune system recovers, it may mount an inflammatory response to existing, previously silent infections such as Mycobacterium avium infection, cytomegalovirus, Pneumocystis jirovecii pneumonia or tuberculosis, which may need further evaluation and treatment. Autoimmune disorders such as Graves’ disease, polymyositis and Guillain-Barré syndrome have also been reported in this setting, sometimes many months after starting treatment.
Redistribution or accumulation of body fat, including central obesity, fat enlargement at the back of the neck, peripheral and facial wasting, breast enlargement and a cushingoid appearance, has been observed in patients receiving antiretroviral therapy. The mechanism and long-term consequences of these changes are currently unknown, and a causal relationship has not been established.