Effects of granisetron and lorazepam, alone and in combination, on the EEG of human volunteers.

1. The EEG effects of granisetron, a potent and selective 5-HT3 receptor antagonist (160 micrograms kg-1), and lorazepam (2.5 mg) were examined in 12 healthy male volunteers. 2. The results indicated that lorazepam had a marked effect on the CNS, significantly increasing power in the slow (1-7 Hz) and fast (13-20 Hz; 21-30 Hz) wavebands whilst reducing power in the mid range (8-12 Hz). 3. In contrast there was no demonstrable effect of granisetron on the EEG at the dose tested, and no evidence of a pharmacodynamic interaction between the two compounds.