Children and zonisamide
Although the FDA has not officially approved zonisamide for children, a number of research studies in children of various ages (even infants) have shown generally good results. It has been effective in reducing many types of seizures, especially primarily generalized seizures, absence seizures, infantile spasms, and myoclonic seizures.
If the dosage is carefully controlled, side effects should not be a problem for most children. In one large study that included children as young as 1 month, side effects were reported for fewer than 20% of children who took zonisamide alone and about 30% who took it along with one or more other seizure medicines. The most common side effects in this study involved problems with thinking or behavior, followed by stomach upset. One dangerous side effect, decreased sweating with fever, occasionally affects young children, but not adults, leading to high fever and possible heatstroke. Advise parents whose children are given zonisamide also to watch for the other symptoms of rare but serious reactions that are listed in the package insert.
Standard dosing recommendations in children are to start zonisamide at 2 to 4 mg/kg per day. The dosage is increased by a similar amount every 2 weeks, depending on how well the child's seizures are controlled and whether any side effects have appeared. Most children do best at about 8 mg/kg per day. The highest dose recommended is 12 mg/kg per day.
In the past, administering low doses to children was difficult, since zonisamide was available only as 100-mg capsules. Smaller capsules, 25 mg and 50 mg, became available in the United States in December 2003.