Side Effects of Valacyclovir: An Introduction
As with any medicine, there are possible side effects of
valacyclovir hydrochloride (
Valtrex®). However, not everyone who takes this drug will experience side effects. In fact, most people tolerate
valacyclovir quite well. If side effects do occur, in most cases, they are minor, meaning they require no treatment or are easily treated by you or your healthcare provider.
(The valacyclovir side effects discussed below are not a complete list of reported side effects. Your healthcare provider can discuss a more complete list with you.)
Common Side Effects of Valacyclovir
Valacyclovir has been thoroughly studied in clinical trials, with many people being evaluated. In these studies, side effects occurring in the group of people taking the drug are always documented and compared to the side effects that occurred in a similar group of people not taking the medicine. Based on these studies, the most common valacyclovir side effects include:
- Headache -- occurring in up to 38 percent of people
- Nausea (upset stomach) -- in up to 15 percent
- Abdominal pain (or stomach pain) -- in up to 11 percent
- Painful menstrual periods -- in up to 8 percent
- Depression -- in up to 7 percent (see Valtrex and Depression)
- Vomiting -- in up to 6 percent
- Joint pain -- in up to 6 percent
- Increased liver enzymes -- in up to 4.1 percent
- Dizziness -- in up to 4 percent.
People with
HIV who take valacyclovir may have additional side effects or side effects that occur more frequently. Other common side effects include an unexplained rash, fatigue (tiredness), and decreased blood counts.
