Common side effects of Dilantin, the drug used to control epileptic seizures

Headache, nausea, vomiting, constipation, dizziness, spinning sensation, drowsiness, slurred speech, loss of balance or coordination, swollen or tender gums, sleep problems (insomnia), nervousness, tremors, rash.

Common side effects include dizziness, nausea, vomiting, tremor, hair loss, weight gain, depression in adults, irritability in children, reduced attention, a decrease in thinking speed. Over the long term, the drug can cause bone thinning, swelling of the ankles, irregular menstrual periods.