The most common side effects are:
- allergic reactions,
- loss of appetite,
- difficulty sleeping,
- muscle pain,
- increased triglyceride levels,
- depression, and
The most serious side effects are severe allergic reactions, pancreatitis, liver failure, and metabolic disturbance (lactic acidosis). Symptoms of an allergic reaction include skin rash, fever, weakness, swelling and difficulty breathing. Abacavir must be stopped as soon an allergic reaction is suspected, and it should not be restarted after an allergic reaction.