The action of SKF 688A (phenoxy-ethyl derivative of dibenamine) upon certain functions of the sympathetic nervous system in man.

A Dibenamine analogue was administered orally to five hypertensive and 10 normotensive subjects over periods from 14 to 21 days. Its adrenergic blocking effect was studied by observing blood pressure , pulse rate, skin temperature of the toes and the pupillary mechanism. Nasal congestion, weakness, listlessness, dizziness, drowsiness and palpitation were persistent sequelae of adrenergic blocking. The drug was found valuable for investigation of autonomous nervous system functions and may hold promise as a therapeutic agent for the treatment of arterial insufficiency and some types of hypertensive subjects. SKF 688A (N-phenoxyisopropyl-N-benzyl-B-chlorethylamine hydrochloride) is a new adrenergic blocking agent. It is structurally and pharmacologically similar to Dibenamine but in contradistinction to Di-benamine, is tolerated orally. In animals, SKF 688A has been shown to be 10 times as potent as Dibenamine intravenously and twice as active by mouth.' The pharmacologic actions of Dibenamine have been described by Nickerson, Goodman, Nomaguchil and others.'-6 Following intravenous injection of Dibenamine in man, a decrease in systolic and diastolic blood pressure was noted in some,3 and orthostatic hypoten-sion and marked pupillary contraction were noted in all patients.4 All authors were able to demonstrate increased peripheral blood flow in patients with peripheral vascular disease. Although Haimovici4 reported orthostatic hypo-tension in all patients tested, significant change in the resting blood pressure occurred only when hypertension was present. A marked reduction in both systolic and diastolic blood pressure was produced in patients with "be-nign" hypertension, but only a slight decrease occurred in those with "malignant" hyperten-sion. Myers and co-workers6 noted temporary symptomatic remission in 7 of 10 patients with hypertensive encephalopathy. More recently, intravenous injection of Dibenainine has been used to reduce intraocular pressure in glau-coma when other medical agents were ineffective .7 8 In general, its use has been limited by the severe systemic manifestations and the necessity for intravenous administration. Preliminary studies with 688A in human subjects9 have shown that postural hypoten-sion, miosis, and vasodilatation follow the use of this drug by mouth as well as intravenously. Moser and co-workers'0 administered 688A to 19 patients. Most cases developed postural tachycardia, miosis and nasal congestion. Extreme postural hypotension developed in one case. The blood pressure fell to normal or slightly above in six of nine hypertensive patients under the age of 50. The fall in blood pressure was maintained as long as the drug was continued, but rose within 36 to 72 hours after the drug had been …