Side Effects of Zonisamide

While most people have no problems when taking zonisamide, side effects can still occur. Commonly reported side effects include drowsiness, irritability, and fatigue. These side effects are generally mild; however, serious side effects of zonisamide are possible. If you experience side effects such as hallucinations, trouble breathing, or a worsening fever, seek immediate medical attention.

 

Side Effects of Zonisamide: An Introduction

As with any medicine, side effects are possible with zonisamide (Zonegran®); 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 are easily treated by you or your healthcare provider.
 
(This article covers many, but not all, of the possible side effects with zonisamide. Your healthcare provider can discuss a more complete list of zonisamide side effects with you.)
 

Common Side Effects of Zonisamide

Zonisamide 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, the most common side effects of zonisamide included:
 
  • Drowsiness -- in up to 17 percent of people
  • Loss of appetite -- up to 13 percent
  • Headaches -- up to 10 percent
  • Agitation or irritability -- up to 9 percent
  • Nausea -- up to 9 percent
  • Fatigue -- up to 8 percent.
     
Other common side effects (occurring in 2 to 6 percent of people) included:
 
(Side Effects of Zonisamide Continued: Page 2)
Written by/reviewed by: Kristi Monson, PharmD; Arthur Schoenstadt, MD
Last reviewed by: Kristi Monson, PharmD;