Adrenergic blocking agents in the treatment of hypertension

The adrenergic blocking agents, bretylium tosylate and guanethidine, have been studied in 50 patients. They are both potent hypotensive agents. In so far as they cause no constipation, dryness of the mouth, or paralysis of visual accommodation, they constitute a distinct advance beyond the ganglionic blocking agents. Of the two compounds studied, guanethidine is, on the whole, to be preferred, as it can be given once daily and appears to have a more even action throughout the 24 hours. However, marked tolerance with either compound occurs within 3 to 9 months; thus treatment becomes progressively more difficult. This and the initially required careful titration suggest that both agents should be used only under conditions where good medical control and patient cooperation are available. Under such conditions, and in combination with a thiazide diuretic, these compounds may be of use in the treatment of hypertension, in cases where renal function remains reasonably normal. Given too freely, these interesting new pharmacologic agents may quickly fall into disrepute. Only upon recognition of their limitations will they be given their rightful place in the pharmacopeia.