Comparison of the acute physical and mental effects of ephedrine, fenfluramine, phentermine and prolintane.

Physical and mental effects of a single oral dose of ephedrine (ephedrine HCl 30 or 40 mg), fenfluramine (fenfluramine HCl 15 or 20 mg), phentermine (7.5 or 11.25 mg) and prolintane (prolintane HCl 10 or 20 mg) were compared in a double-blind placebo-controlled study. Each group consisted of 16-43 healthy volunteer medical students. The subjects fasted for at least 3 hr before drug administration and further until the end of the experiment. All the parameters were measured just prior to giving the drug, and 1.5 hr and 2.5 hr afterwards. Ephedrine significantly increased systolic blood pressure (p less than 0.05) and heart rate (p less than 0.01), whereas the other sympathomimetics affected these parameters only slightly or negligibly. None of the drugs markedly changed the tapping rate of the dominant hand. Mental activity was evaluated with a self-rating check list consisting of various mental modalities. None of the sympathomimetics significantly modified the mental activity. Memory, learning and concentration ability were evaluated with sign recording and digit span tests. In the digit span test no changes were obtained. In the sign recording test (for 3 min), phentermine increased significantly the recording score at both 1.5 hr (p less than 0.05) and 2.5 hr (p less than 0.005), and prolintane at 2.5 hr (p less than 0.05) after drug administration. The results suggest that in the doses given, which are commonly used in medical practice, ephedrine has the most pronounced cardiovascular effects, while phentermine and prolintane seem to be most active in the performance of some mental tasks.

RCT Entities:   Population Interventions Outcomes