A single-dose study of the
beta-carboline,
ZK 95962, on photosensitive generalized paroxysmal activity in the EEG was conducted in 6 patients with primary
generalized epilepsy. Four of the patients were newly diagnosed and did not receive any
antiepileptic drug or other medication during the study. Two were receiving current
therapy with
carbamazepine. A double-blind cross-over study with 2
injections of
ZK 95962 (20 micrograms/kg
body weight repeated 10 min after 1st injection) and 2 placebo
injections were carried out in a randomized order, with 4 h intervals between the
injections with active
drug and placebo. On the day before the trial, the sensitivity range (standardized photosensitivity range, SPR) was determined hourly using flash frequencies of 2, 6, 8, 10, 15, 20, 30 and 40 Hz for 4 sec in ascending and descending order until generalized spikes or spike waves occurred. A significant reduction in photosensitivity was observed 2-12 min after injection of
ZK 95962 in all patients, lasting 2-3 h. No change in the SPR was observed after placebo
injections. The feelings of uneasiness and
myoclonic jerks, provoked by photostimulation, were also abolished by
ZK 95962, but not by placebo
injections. Side effects, including sedation were not observed. The results suggest that
benzodiazepine receptor ligands such as
ZK 95962 may be potent
antiepileptic drugs.