Nicotinic acid treatment of skin disorders

Abstract

Nicotinic add treatment of cutaneous disorders of vascular origin of the lower extremities has been widely proposed (Winkelmann et al, 1974; Physicians Desk Reference, 1976) but this therapy has not been subjected to a controlled critical evaluation. Since the therapeutic effect of nicotinic acid is proposed to be relaxation of vascular smooth muscle, we undertook to examine the effect of nicotinic acid on the pretibial arteriolar pressure in maximally vasodilated skin (Nickerson, 1970). We examined six patients with stasis dermatitis. The patients were given nicotinic acid, 100 mg four times daily, for 2 weeks and placebo, four times daily for 2 weeks in a double-blind crossover fashion. The pretibial arteriolar pressure in maximally dilated skin was measured using a modification of the method of Chavatzas & Jamieson (1974). This technique consists of visualizing a histamineinduced flare through a transparent window in a sphygmomanometer cuff. The pressure at which the flare reappeared after occlusion was recorded. This method correlated well with xenon-washout studies (Chavatzas & Jamieson, 1976). The pretibial arteriolar pressure and the ratio of pretibial arteriolar pressure to brachial systolic pressure were examined at weekly intervals during nicotinic acid treatment and control (placebo) periods. We investigated the pretibial arteriolar pressure and the ratio of pretibial arteriolar pressure to brachial systolic pressure after a single dose of nicotinic acid, 100 mg by mouth. We also monitored the degree of cutaneous involvement, viz., a subjective quantification of dermatitis. We examined the fasting sera at weekly intervals for changes in triglycerides and cholesterol. Finally, one of us recorded the incidence of side effects. Since flushing was felt to be so common, the tabulator of side effects was not involved in the collection of any of the other data. In analysis of the data we foimd no consistent changes in pretibial arteriolar pressure, brachial systolic pressure, their ratio, cutaneous lesions, or serum lipids. Flushing was reported by all patients. Pruritus and nausea with occasional emesis were also reported by some patients. In summary, we found no effect of nicotinic acid on the pretibial arteriolar pressure, which should reflect the proposed therapeutic relaxation of vascular smooth muscle. The general use of nicotinic acid treatment for cutaneous disorders of vascular origin must remain questionable until further studies are done. (Author's note: Data available upon request.)