Age and severe adverse drug reactions caused by nifedipine and verapamil. Gruppo Italiano di Farmacovigilanza nell' Anziano (GIFA).

The association of age with risk for severe adverse drug reactions (SADRs) was studied in 2371 and 862 hospitalized patients taking nifedipine and verapamil, respectively. Nifedipine caused hypotension (n = 22), tachycardia (n = 3), and acute renal failure (n = 1) (total SADR rate, 1.1%, 26/2371). Verapamil caused hypotension (n = 3), bradycardia (n = 9), and atrioventricular blocks (n = 2) (total SADR rate, 1.6%, 14/862). The mean age of patients with and without SADRs was for nifedipine 77.1 +/- 1.7 and 71.8 +/- 0.8 years, respectively (p < 0.05), and for verapamil 73.4 +/- 2.9 and 73.1 +/- 0.4 years, respectively. Sex, length of stay, comorbidity, polypharmacy, intake of slow-release preparations, daily dosage, and new intake of calcium antagonists were examined as potential confounders of the age-SADR association. After adjusting for potential confounders, age was significantly and independently associated with SADRs caused by nifedipine, but not with SADRs caused by verapamil (OR = 1.69, 95% CI = 1.05-2.72 and OR = 1.06, 95% CI = 0.63-1.68 for 10-year increase, respectively). Although nifedipine and verapamil did not have significantly different rates of SADRs, an age-related gradient was found only for nifedipine.