A double-blind comparison of chlormethiazole and dichloralphenazone: a sedative/hypnotic in geriatric medicine.

In a double-blind crossover trial, chlormethiazole was compared with dichloralphenazone and placebo in 38 elderly patients requiring night-time sedation. Chlormethiazole was significantly superior to dichloralphenazone and placebo for the parameters 'heavy sleep' and'time of onset of sleep'. The incidence of side-effects did not significantly differ whilst on placebo. Because of the high incidence of "placebo reactors', a sub-group who slept badly whilst on placebo were further analysed. The data indicated a definitive trend suggesting that the difference found in the overall material was valid for the sub-group of 17 subjects. Problems of placebo reactors in clinical trials are discussed and the view supported that 'placebo reactors' should be excluded by a preliminary screening test before admission to double-blind controlled trials evalvuating hypnotic drugs.