Seizures caused by accidental dimenhydriante intoxication

The safety of dimenhydrinate is supposed to be excellent. Typical side effects are sedation and an anticholinergic syndrome. A 13-months-old girl suffered from three generalized tonic-clonic seizures for several minutes within a total period of nine hours. History revealed that the child received a total of five Vomex® suppositories à 40mg during the previous two days (i.e. 23mg dimenhydrinate per kg body weight). The first seizure occurred ten hours after the last administration. The plasma level of dimenhydrinate was 210µg/l approximately one hour after the first seizure. Electroencephalography showed no pathological signs and an MRI scan of the brain was normal except of several small gliotic spots. There were no further seizures in the next 12 months.

Infants have an increased risk to develop dimenhydrinate intoxication, especially in cases where suppositories were given repeatedly because of intermittent defecation.