Lamivudine: What It Is, How It Works, and What You Need to Know

When you hear lamivudine, a nucleoside reverse transcriptase inhibitor used to treat HIV and chronic hepatitis B. Also known as 3TC, it's one of the most widely used antiviral drugs in the world—often combined with other medications to stop viruses from multiplying. It doesn’t cure HIV or hepatitis B, but it keeps them under control, helping people live longer, healthier lives. If you’re on a combo pill for HIV, chances are lamivudine is in it—usually paired with tenofovir or emtricitabine.

Lamivudine works by blocking an enzyme called reverse transcriptase, which both HIV and hepatitis B need to copy themselves. Without that enzyme, the virus can’t spread in your body. That’s why it’s used in HIV treatment, a combination therapy designed to suppress viral load and prevent drug resistance. For hepatitis B, it reduces liver damage and lowers the chance of cirrhosis or liver cancer. But it’s not a one-size-fits-all solution. Some people develop resistance over time, especially if doses are missed. That’s why sticking to the schedule matters more than you might think.

What you might not realize is how often lamivudine interacts with other drugs. It’s commonly taken with antiretroviral drugs, medications that target different stages of the HIV life cycle, but combining it with certain kidney-affecting meds or other antivirals can raise your risk of side effects. It’s also linked to rare but serious issues like lactic acidosis and liver problems—especially in people with existing liver disease. That’s why regular blood tests and open talks with your doctor are non-negotiable.

You’ll find plenty of posts below that dig into how lamivudine fits into bigger picture issues: why some patients need to switch from brand to generic versions, how drug quality can vary between manufacturers, and what happens when you mix it with herbal supplements or other prescriptions. There are also guides on managing side effects, understanding FDA approvals for generics, and what to do if your insurance denies coverage. Whether you’re just starting treatment or have been on lamivudine for years, these resources help you ask the right questions and stay in control of your health.