The effect of baclofen on objective and subjective sleep measures in a model of transient insomnia

Insomnia is a common medical complaint. Current pharmacologic treatments have modest efficacy and numerous side effects. Baclofen is a gamma-aminobutyric acid (GABA)b receptor agonist used to treat spasticity in various medical conditions. Several studies noted that baclofen, when used to treat sleep related disorders, resulted in improvement in sleep parameters. Measures of insomnia, however, were not assessed in those studies. To date, baclofen has not been assessed for efficacy in the treatment of insomnia.

We randomized 20 healthy subjects to baclofen or placebo in a cross over design. All subjects underwent two polysomnograms (PSG) assessing sleep parameters. Baclofen or placebo was given 90 min prior to lights out in random order for each subject. Lights out occurred two hours earlier than the subject's median habitual bedtime.

Baclofen resulted in significantly less objective wake after sleep onset and stage 1 sleep, and significantly increased total sleep time (TST), sleep efficiency, and stage 3/4 sleep. There was no effect on sleep onset latency (SOL). Self-report variables indicated significantly less subjective awakenings from sleep and increased subjective sleep quality. There was no effect on subjective TST or subjective SOL.

This study showed that baclofen was superior to placebo with regard to several objective and subjective measures used to assess sleep quality. These data support the notion that baclofen shows promise as an effective hypnotic drug.