Comparative effects of H2-receptor antagonists on subjective and objective assessments of sleep

Clinically, it is common for patients to experience drowsiness in association with consumption of H1-receptor antagonists. Reported side-effects with H2-receptor antagonists include insomnia and somnolence. The present study was designed to assess and compare the effects of three H2-receptor antagonists (cimetidine, famotidine, and ranitidine) on nocturnal and daytime sleepiness.

This is a double-blind crossover study on 12 normal volunteers. Subjects were studied under conditions of placebo, cimetidine (400 mg b.d.), famotidine (20 mg b.d.), and ranitidine (150 mg b.d.) for one week. Sleep was assessed at the end of each one-week interval via polysomnographic evaluation conducted on nights 6 and 7 of drug administration. On the day between the two nights in the sleep laboratory, a multiple sleep latency test was conducted.

The results revealed a significant reduction in the sleep onset latency with famotidine administration, but since there were no effects of any of the medications in the multiple sleep latency test, this finding is of dubious clinical significance. Cimetidine revealed a small increase in subjective estimates of sleepiness. No effects on sleep-related respiratory parameters were noted.

This study demonstrates the lack of effect of peripheral administration of H2-receptor antagonists on sleep stages, while subjective or objective assessment of daytime alertness revealed small effects of famotidine and cimetidine.