Lamivudine: What It Is, How It Works, and What Alternatives Exist

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 oldest and most trusted antiviral drugs still in use today. Unlike newer pills that target multiple stages of the virus, Lamivudine works by blocking the enzyme HIV and HBV need to copy themselves. It doesn’t cure either infection, but it stops them from spreading fast enough to wreck your immune system or liver.

Lamivudine rarely stands alone. It’s almost always paired with other drugs — like tenofovir or efavirenz — in combo regimens. That’s because using it by itself lets the virus mutate and become resistant. You’ll find it in pills like Trizivir and Epzicom, where it teams up with other antivirals to keep the virus under control. For hepatitis B, it’s often the first choice for people who can’t take stronger meds, especially if they’re pregnant or have kidney issues. But even then, doctors watch closely. Long-term use can lead to resistance, and some people report headaches, nausea, or tiredness early on.

Related to Lamivudine are other antiretroviral drugs like Tenofovir, a backbone drug in modern HIV treatment that’s less likely to cause resistance, and Emtricitabine, a close cousin of Lamivudine that works the same way but is often preferred in newer regimens. Then there’s Entecavir, a top choice for hepatitis B when Lamivudine stops working. These aren’t just alternatives — they’re upgrades, designed to be stronger, longer-lasting, and harder for the virus to escape.

If you’re on Lamivudine, you’re not just taking a pill. You’re part of a long-term strategy. That means sticking to your schedule, getting regular blood tests, and knowing when to switch. Many people start here because it’s affordable and well-studied, but if resistance shows up, your doctor will move you to something like tenofovir or dolutegravir. The goal isn’t just to keep the virus low — it’s to keep you healthy for decades.

Below, you’ll find real comparisons and guides that break down how Lamivudine stacks up against other options, what side effects actually matter, and how to spot when it’s time to change course. These aren’t theory pieces — they’re practical tools from people who’ve lived with these treatments, fought resistance, and found what works.