The effects of two single doses of tramadol on sleep: a randomized, cross-over trial in healthy volunteers

Background and aim The effects of analgesic drugs on sleep are poorly under stood. We investigated short- and medium-term effects of tramadol on sleep structure. Methods Eight healthy volunteers received a placebo (predrug placebo-night) , then, in a randomized, double-blind, cross-over fashion a single oral dos e of tramadol 50 mg or 100 mg (drug-night), and finally, again a placebo (p ostdrug placebo-night). Standardized polysomnography (electroencephalogram, electro-oculogram, submental electromyogram) was continuously recorded dur ing placebo- and drug-nights. Results During drug-nights both doses of tramadol significantly increased t he duration of stage 2 sleep, and significantly decreased the duration of s low-wave sleep (stage 4). Tramadol 100 mg but not 50 mg significantly decre ased the duration of paradoxical (rapid eye movement) sleep. In the placebo -night after tramadol 100 mg (but not after 50 mg) duration of stage 2 slee p was significantly shorter, and duration of stage 4 sleep was significantl y longer compared with the predrug placebo-night. Conclusion In healthy volunteers, a single dose of tramadol 50 mg disturbs sleep in the night of drug application. With 100 mg, sleep is disturbed in both the night of drug application and in the subsequent night.