Effect of Amlodipine on Blood Pressure Responses in Local and Whole-body Cooling in Normotensive Men

Abstract

The objective of this study was to determine the ability of amlodipine (CAS 88150-42-9, Norvasc) to affect the cold-induced rise of blood pressure and heart rate in normotensive men. Fourteen normotensive men underwent a one-hand cold pressor test (+10 degrees C, 5 min) and a whole-body cold air exposure test (+5 degrees C, 45 min) in a crossover study with and without amlodipine at a seven-day interval. Amlodipine decreased the levels of initial systolic and diastolic blood pressure before both tests, but it had no influence on heart rate. During the cold pressor test, amlodipine lowered the peak diastolic pressure from 96 +/- 10 mmHg (mean +/- SD) to 92 +/- 10 mmHg (p = 0.024). The rise of diastolic blood pressure was 13 +/- 7 mmHg with amlodipine and 16 +/- 8 mmHg without amlodipine (p = 0.138). During the whole-body cold air exposure test, amlodipine decreased the systolic pressure from 135 +/- 2 mmHg to 133 +/- 3 mmHg (p = 0.008) and the diastolic pressure from 88 +/- 2 mmHg to 86 +/- 1 mmHg (p = 0.005). However, the cold-induced rise of blood pressure in whole-body cooling was not affected by amlodipine, because it also decreased the initial values. Amlodipine did not affect the initial or cold-induced changes of heart rate in these tests. In conclusion, in normotensive men amlodipine lowers the peak of diastolic blood pressure in a cold pressor test. In whole-body cold air exposure, amlodipine slightly decreases the levels of both systolic and diastolic pressures, but has no effect on the cold-induced rise of blood pressure. Amlodipine does not prevent the cold-induced physiological responses of blood pressure or heart rate.