Younger Females Are at Greater Risk of Vasodilation-Related Adverse Symptoms Caused by Dihydropyridine Calcium Channel Blockers: Results of a Study of 11,918 Japanese Patients

Adequate control of blood pressure in younger females is of crucial importance, because they are at higher risk of hypertensive target organ damage compared with males of similar age. In addition, female sex is a risk factor for adverse effects of antihypertensive drugs, especially dihydropyridines. This study set out to assess the incidence of adverse reactions during dihydropyridine use in a real-life clinical setting, focusing on the influence of female sex and age. The incidence of adverse reactions to dihydropyridine calcium channel blockers were investigated in 11,918 Japanese patients who participated in the Drug Event Monitoring project of the Japan Pharmaceutical Association conducted in Kumamoto prefecture. A multiple logistic regression analysis was used to determine the association between the incidence of adverse symptoms and female sex, with adjusted odds ratios (ORs) and 95 % confidence intervals (95 % CIs). Vasodilation-related adverse symptoms occurred significantly more often in females than in males (OR 1.87, 95 % CI 1.28-2.71, p = 0.001). Furthermore, among females only, the younger age group (< 50 years) complained of vasodilation-related symptoms more frequently (OR 2.39, 95 % CI 1.02-5.59, p = 0.045) and the older age group (a parts per thousand yen80 years) complained of vasodilation-related symptoms less frequently (OR 0.56, 95 % CI 0.33-0.95, p = 0.030) than the middle age group (50-79 years). To the best of our knowledge, this is the first report showing that younger females are at high risk for vasodilation-related adverse symptoms during dihydropyridine use in a real-life clinical setting. These results should be verified in clinical studies using larger samples of young patients and more parameters.