A longitudinal study of the mechanisms of action of debrisoquine and propranolol.

1 The mode of action of hypotensive drugs is not necessarily the same early and late in a course of treatment. 2 It was aimed to study this possible difference of effects for the drugs debrisoquine and propranolol, using a clinical trial design and measuring as many cardiovascular functions as possible by noninvasive methods in out-patients. 3 Several well known effects of these drugs were noted; in addition it was found that in some subjects there was a small but progressive salt retention during propranolol treatment, that the displacements of the slopes in baroceptor function tests were different for the two drugs tested, and that venous distensibility was reduced at first with propranolol but soon increased again. 4 It is useful to combine longitudinal measures of body functions with a clinical trial when studying mechanisms of drug action.