Harvoni (ledipasvir and sofosbuvir) appears to have few side effects. In clinical trials, the most common adverse reactions were fatigue and headache. Some people also reported nausea, diarrhea and insomnia. Fewer than 1% of people stopped taking Harvoni because of these problems. However, Harvoni can interact with other medications, and in some cases this can worsen the side effects caused by those drugs. For example, Harvoni can raise the levels of rosuvastatin (Crestor) in the blood, increasing the risk of muscle pain and damage. This, in turn, can lead to liver and kidney problems.
While you are taking Harvoni, if you develop any side effects that concern you or don't go away, be sure to tell your doctor.