Exacerbation of human cataplexy by prazosin.

A middle-aged woman with narcolepsy developed a pronounced exacerbation of cataplexy within 3 days of beginning treatment for hypertension with prazosin, an alpha 1-adrenoceptor antagonist. At times, episodes of cataplexy were virtually continuous (status cataplecticus), and there was only partial amelioration with tricyclic antidepressants. Cataplexy improved when prazosin was discontinued. These findings are similar to the reported effects of prazosin on cataplexy in narcoleptic dogs; they support a role for altered alpha 1-adrenoceptor function in narcolepsy.