The following is not a full list of side effects. Side effects cannot be anticipated. If any develop or change in intensity, tell your healthcare provider as soon as possible. Only your healthcare provider can determine if it is safe for you to continue taking this medication.
Hepsera can cause a serious condition called lactic acidosis (a build-up of an acid in the blood). This can be a medical emergency and may need to be treated in the hospital. Call your healthcare provider right away if you feel very weak, tired, dizzy, or lightheaded; have unusual muscle pain or stomach pain with nausea and vomiting; trouble breathing; you feel cold, especially in your arms and legs; or have a fast or irregular heartbeat.
Hepsera can also cause serious liver problems, with liver enlargement and fat in your liver. Call your healthcare provider right away if you develop yellowing of your skin or the whites of your eyes, dark-colored urine or light-colored stools, loss of appetite for several days or longer, feel sick to your stomach, or have lower abdominal (stomach area) pain.
If you have HBV infection and you stop taking Hepsera, you may get a "flare-up" of your hepatitis. A "flare-up" is when the disease suddenly returns in a worse way than before. If you have HBV and stop taking Hepsera, your healthcare provider may monitor you closely for several months to check for hepatitis that could be getting worse. Talk to your healthcare provider about appropriate HBV treatment if necessary.
Hepsera may cause serious kidney problems. Your healthcare provider will order tests to check your kidney function during your treatment with Hepsera.
More common side effects may include: weakness, headache, stomach pain, diarrhea, nausea, indigestion, increased intestinal gas.
Less common side effects may include: muscle pain or weakness, weakening of bones, inflammation of your pancreas.