Hi, Thanks for posting in HCM. I understand your concern. Phenytoin is an anti-epileptic medication which is administered to prevent occurrence of seizures (convulsions) by slowing down impulses in the brain. Commonly encountered side effects which one needs to be aware of while taking this medication include: hepatic necrosis, depression, confusion, fatigue, enlarged gums, constipation, giddiness, ataxia, muscle weakness, hypertrichosis (increased hair growth), nervousness, tremor of hands, numbness, dizziness, drowsiness, tremor, irritability, excitement, mood changes and restlessness. Any side effect which becomes bothersome or makes one intolerant should make you seek medical attention promptly. Phenytoin is a known teratogen. Hence its intake during pregnancy causes congenital anomalies in growing infant. Hope the information provided would be helpful. All the best.