Treatment of neurogenic orthostatic hypotension with amezinium metilsulfate, a new indirect sympathomimetic drug

Amezinium metilsulfate is a new, indirectly acting sympathomimetic drug which exclusively affects postganglionic sympathetic neurons and inhibits both intraneuronal monoamine oxidase and norepinephrine reuptake. We examined the short-term effects of amezinium in five patients with severe neurogenic orthostatic hypotension. Single-dose administration of amezinium (10 mg) raised both the supine and sitting mean blood pressures by 15 to 45 mm Hg for 8 hours, with a slight increase in the plasma norepinephrine level. Repeated administration of amezinium (10 to 40 mg/d) produced an increase in sitting blood pressure in three patients and improvement of the orthostatic symptoms in all patients without remarkable recumbent hypertension. The heart rate was increased in two patients. The results indicate that amezinium is of therapeutic value for the treatment of neurogenic orthostatic hypotension. The adrenergic effect of amezinium on the blood pressure and heart rate apparently was related to a slight increase in endogenous norepinephrine in the presence of alpha- and beta-adrenoreceptor supersensitivity.