A patient showing sleep paralysis associated with the reversible MAO-A inhibitor moclobemide is presented. A MEDLINE search did not ยฎnd 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 ยฎrst 300 mg he had ยฎve 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 ยฎve 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;. This onยฑoยฑonยฑo 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 . It may respond to REM-suppressing antidepressants (Sharpley and Cowen, 1995):