Side effects and their incidence levels vary depending on the type of anticonvulsant being taken. For example, up to 30 percent of patients taking carbamazepine may experience side effects.

Some of the more common side effects associated with anticonvulsant use include:

• Gastrointestinal complaints (e.g., nausea, vomiting, diarrhea). These common side effects generally improve if the medication is taken with milk or food. Lowering dosage levels or taking the medication at bedtime can also reduce these side effects.
  
  
• Central nervous system (CNS) complaints. These may include sedation, dizziness, drowsiness, blurred vision and lack of coordination. Lowering dosage levels can also reduce these side effects.
  
  
• Skin changes. Some anticonvulsants, especially lamotrigine,  may cause a potentially dangerous rash that may develop into Stevens Johnson syndrome, an extremely rare but potentially fatal skin disease. Because of this link, most of these medications are discontinued when a rash develops. Anticonvulsants may also make a person’s skin more sensitive to sunlight.
  
  
• Changes in blood chemistry. Most anticonvulsants require frequent blood tests to monitor their blood, chemical and compositional levels (e.g., calcium levels, white blood cell count, red blood cell count, liver enzymes). Most of these changes are harmless, but some can be quite dangerous. Divalproex can reduce the ability of the blood to clot in some patients. In rare cases, carbamazepine can result in significant and dangerous drops in levels of white or red blood cells.

Other common side effects of anticonvulsants include:

• Drowsiness
• Weight gain
• Hair loss
• Dizziness
• Incoordination
• Blurred vision
• Shaky hands (tremors)
• Liver disease or failure (rare)

CNS effects, cardiovascular effects and gastrointestinal effects are potential side effects associated with nearly all anticonvulsants. Other major side effects associated with specific anticonvulsants used for mental health disorders are as follows: