Eight patients with hypersomnolent, anergic major depression benefited
markedly from treatment with relatively high doses of phenelzine or
tranylcypromine but experienced intense afternoon somnolence and disrupted
sleep. Reducing the dose of monoamine oxidase inhibitor (MAOI) or
substituting isocarboxazid sometimes provided relief, but altering the
schedule of drugs or meals did not. Bedtime sedation alleviated the
disrupted sleep but had little effect on daytime somnolence. The mechanism
underlying this side effect is unknown; sleep deprivation, narcolepsy, or
hypotension does not account for it. Patients given an MAOI should be
assessed for this disturbance and cautioned to avoid risk of injury when it
occurs.Abstract Teaser