Side Effects of Famciclovir
Side effects of famciclovir may include migraines, vomiting, and gas. Headaches and nausea were among the most common side effects reported during clinical studies. A few less common but more serious famciclovir side effects include aggressiveness or agitation, yellow eyes or skin, hallucinations, and any signs of an allergic reaction. If you experience these or any other serious side effects, let your healthcare provider know.
As with any medicine, side effects are possible with famciclovir (Famvir®); however, not everyone who takes the medication will experience side effects. In fact, most people tolerate it quite well. If side effects do occur, in most cases they are minor and either require no treatment or can easily be treated by you or your healthcare provider.
(This article covers many, but not all, of the possible side effects with famciclovir. Your healthcare provider can discuss a more complete list of famciclovir side effects with you.)
Famciclovir has been studied thoroughly in clinical trials. In these studies, the side effects that occur in a group of people taking the drug are documented and are then compared to side effects that occur in another group of people not taking the medicine. This way, it is possible to see what side effects occur, how often they appear, and how they compare to the group not taking the medicine.
In these studies, some of the most common side effects of famciclovir included:
- Headaches -- in up to 22.7 percent of people
- Nausea -- up to 12.5 percent
- Diarrhea -- up to 7.7 percent
- Painful menstrual cramps -- up to 7.6 percent
- Vomiting -- up to 4.8 percent
- Fatigue -- up to 4.8 percent
- Gas -- up to 4.8 percent.
Some other common famciclovir side effects, occurring in 1 percent to 4 percent of people, included:
- Unusual sensations, such as numbness, burning, or tingling
- Migraine headaches
- Abdominal pain (or stomach pain).