Abacavir — what it is and why it matters

Abacavir is an antiretroviral drug used to treat HIV. It’s part of the NRTI class (nucleoside reverse transcriptase inhibitors). Doctors commonly prescribe it as a single agent combined with other HIV meds, often as a fixed-dose pill with lamivudine or with dolutegravir. The goal is the same: lower your viral load and keep your immune system working.

How abacavir works and typical dosing

Abacavir blocks a key enzyme HIV needs to reproduce. That slows the virus and helps your CD4 counts recover. For adults, the usual total daily dose is 600 mg — either 300 mg twice a day or 600 mg once daily depending on the combination pill you’re given. There’s also an oral solution for people who need it.

Doctors pick abacavir when it fits the whole treatment plan. It’s in many single-tablet regimens, which makes sticking to treatment easier. Still, follow the exact dose and schedule your clinician gives you.

Side effects, testing, and safety tips

The most serious risk with abacavir is a hypersensitivity reaction. It can show up as fever, rash, nausea, stomach pain, and breathing problems. This usually happens in the first six weeks. If you get these symptoms, stop the drug right away and contact your provider. Never restart abacavir after a hypersensitivity reaction — it can be life-threatening.

To prevent that reaction, doctors test for HLA-B*5701 before starting abacavir. If the test is positive, abacavir is not recommended. If it’s negative, the risk drops but you still need to watch for symptoms.

Other side effects can include headache, tiredness, and nausea. Rarely, people can develop serious liver problems or lactic acidosis with NRTIs. Report symptoms like unexplained stomach pain, severe tiredness, or yellowing of the skin right away.

Abacavir has relatively few major drug interactions, but always tell your clinician about other medicines, supplements, and herbal products you take. That includes TB and antifungal treatments. If you’re pregnant, planning pregnancy, or breastfeeding, discuss risks and benefits with your provider — abacavir is used in pregnancy but the care plan should be individualized.

Stick to your meds. Missing doses can let the virus rebound and lead to resistance. Store abacavir at room temperature away from moisture. Keep it in its original container and out of reach of children.

If you’re worried about side effects, affordability, or where to get refills, ask your clinic or pharmacist. Many clinics offer support programs, and combination tablets can cut pill burden. Test for HLA-B*5701 first, know the signs of hypersensitivity, and keep open communication with your care team — that’s the clearest path to safe, effective HIV treatment with abacavir.