Continuous transdermal nitroglycerin therapy for menopausal hot flashes: a single-arm, dose-escalation trial

Abstract

Objective: To describe the efficacy and tolerability of continuous nitroglycerin for treatment of hot flashes.

Methods: Perimenopausal and postmenopausal women reporting at least seven hot flashes per day were recruited into a single-arm, dose-escalation trial of continuous transdermal nitroglycerin. Participants were started on a generic 0.1 mg/hour nitroglycerin patch applied daily without patch-free periods. During 4 weeks, participants escalated dosage weekly to 0.2, 0.4, or 0.6 mg/hour as tolerated, then discontinued nitroglycerin during the final week. Changes in hot flash frequency and severity were assessed using symptom diaries. Paired t tests examined change in outcomes between baseline and maximal-dose therapy and after discontinuation of nitroglycerin.

Results: Of the 19 participants, mean age was 51.4 (±4.3) years. Women reported an average 10.6 (±3.0) hot flashes and 7.1 (±3.8) moderate-to-severe hot flashes per day at baseline. Eleven women escalated to 0.6 mg/hour, three to 0.4 mg/hour, two to 0.2 mg/hour, and one remained on 0.1 mg/hour nitroglycerin. Two discontinued nitroglycerin before the first outcomes assessment. Among the remaining 17 women, the average daily frequency of hot flashes decreased by 54% and the average frequency of moderate-to-severe hot flashes decreased by 69% from baseline to maximum-dose therapy (P < 0.001 for both). After discontinuing nitroglycerin, participants reported an average 23% increase in frequency of any hot flashes (P = 0.041) and 96% increase in moderate-to-severe hot flashes (P < 0.001).

Conclusions: Continuous nitroglycerin may substantially and reversibly decrease hot flash frequency and severity. If confirmed in a randomized blinded trial, it may offer a novel nonhormonal hot flash treatment.

Figure 1

Hot flash frequency and severity were assessed by symptoms diaries in which women recorded each hot flash they experienced and rated its severity as mild, moderate, or severe. The average daily frequency of 1) any hot flashes, and 2) moderate-to-severe hot flashes, was determined over a 7-day period at baseline (pre-treatment), during successive 7-day periods on each dose of nitroglycerin, and during a 7-day period during weaning and discontinuation of nitroglycerin. Among the 17 participants providing outcomes data, maximum dose of nitroglycerin was 0.6 mg/hr for 11 women, 0.4 mg/hr for 3 women, 0.2 mg/hr for 2 women, and 0.1 mg/hr for one woman.