Hi, I had gone through your question and understand your concern for your mother. I think you are talking of TENOFOVIR (brand name - Viread). She is probably suffering from chronic hepatitis due to hepatitis B virus infection. Yes it has adverse effects.The most common side effects associated with tenofovir include nausea, vomiting, diarrhea, and asthenia. Less frequent side effects include hepatotoxicity, abdominal pain, and flatulence. Do not worry. It would have been great had I examined your mother on my own. Your doctor must have prescribed it after examining her and after considering the benefits and adverse effects. These antiviral drugs like tenofovir and entecavir are prescribed in chronic Hep-B patients. I would suggest you to stick to the doctor s advice. If there are unbearable adverse effects , talk to your doctor. He/she can examine her and correlate clinically. Hope this answers your question. If you have additional questions or follow up questions then please do not hesitate in writing to us. I will be happy to answer your questions. Wishing your mom s good health.