Bethanidine sulfate, a new drug that inhibits the sympathetic nervous system, was administered alone or in combination with other antipressor agents to 23 hypertensive patients. Its antipressor potency, which was enhanced by concomitant oral administration of a diuretic, was comparable to that of guanethidine sulfate, which it resembles pharmacologically. Both agents produced orthostatic hypotensive symptoms, impotence, and failure of ejaculation. Unlike guanethidine, bethanidine did not cause troublesome diarrhea in any patient. The shorter onset and duration of action of bethanidine make it possible to minimize morning hypotension and afternoon hypertension by giving smaller doses at bedtime than at midday—a manipulation of dosage that is ineffective with guanethidine. While neither bethanidine nor guanethidine was shown to be clearly superior to the other, some patients tolerated one drug better than the other, and consequently it is useful to have both potent antipressor agents available.
Gifford RW. Bethanidine Sulfate— A New Antihypertensive Agent. JAMA. 1965;193(11):901-905. doi:10.1001/jama.1965.03090110039011