Moclobemide-associated sleep paralysis

Abstract

Sirs,A patient showing sleep paralysis associated with the reversible MAO-A inhibitor moclobemide is presented. A MEDLINE search did not ®nd similar reports.A 70-year-old man with major depressive disorder recurrence was treated with moclobemide, 150 mg/day for 1 week, then 300 mg/day in the morning. The night he took his ®rst 300 mg he had ®ve episodes during sleep, each one lasting for seconds, of wakefulness associated with inability to move, speak, breathe, and terror. He had never had similar episodes in the past. He continued to take moclobemide for a week, and every night sleep was interrupted by four to ®ve brief episodes of paralysis and terror. Then moclobemide was discontinued for 3 days, during which the sleep episodes did not reappear. Moclobemide was then restarted, 300 mg/ day in the morning, for 2 weeks. Sleep episodes reappeared. Moclobemide was again discontinued. During the following 3 weeks, sleep episodes did not reappear. During this trial he remained mildly depressed. He had been taking the angiotensin converting enzyme (ACE) inhibitor fosinopril, 20 mg/day, for 3 years, for hypertension. This patient's sleep episodes correspond to descriptions of sleep paralysis (American Psychiatric Association, 1994;Dahlitz and Parkes, 1993). This on±o±on±o trial suggests a causal relationship between moclobemide and sleep paralysis. During this period he did not have sleep disorders associated with sleep paralysis (narcolepsy, cataplexy, sleep-related hallucinations).Sleep paralysis is caused by a dissociation between alertness and rapid eye movements (REM)-associated muscle atonia (Hishikawa and Shimizu, 1995). It may respond to REM-suppressing antidepressants (Sharpley and Cowen, 1995): tricyclic antidepressants (Aldrich, 1992;Mitler et al., 1990). irreversible nonselective MAO inhibitors (Gernaat et al., 1995), and selective serotonin reuptake inhibitors (Koran and Raghavan, 1993;Dahlitz and