Symptoms of overdose can be similar to the medication’s side effects, but are usually more severe. Overdose of anticonvulsants is dangerous and can lead to coma or death. Common symptoms include:

• Nausea
• Vomiting
• Drowsiness
• Confusion
• Over- or underactive reflexes
• Seizures
• Trouble breathing

Regular monitoring of blood levels can help prevent anticonvulsants from building up to toxic levels. Blood levels may be monitored for the first month, and every one to three months thereafter.