Dose-related side effects
Side effects most often reported by patients taking Felbatol have included:

• decreased appetite and weight loss
• nausea
• insomnia
• headache

Some other side effects mentioned even less often were:

• poor coordination or tremor
• vision problems
• dizziness
• vomiting
• mood changes or anxiety
• somnolence (when part of polytherapy)

If these problems do not diminish within several days, a reduction in the dose of Felbatol often will solve the problem. Problems with somnolence also may be helped by splitting the dose or giving the largest dose at bedtime.

Idiosyncratic reactions
Rash is seen in a small percentage of patients. This reaction usually occurs early in the course of therapy. Most patients will need to stop taking Felbatol and replace it with a different antiepileptic medication.