Phenylpropanolamine and blood pressure: a review of prospective studies

The use of phenylpropanolamine (PPA) as an anorectic has provoked commentary and disagreement. Its use in the last decade has been associated with a series of adverse clinical events. As in all case reports, these associations may be noncausal, particularly in light of PPAs extensive use. We have reviewed prospective clinical trials in which the administration of PPA was planned to assess impact on blood pressure. Many of these employ sedentary, healthy volunteers but also included are studies of overweight, moderately hypertensive, and ambulatory subjects. An analysis of such studies leads us to believe that PPA is an appropriately marketed over-the-counter drug, with an acceptable margin of safety. Further, we have reanalyzed our own earlier published data, which indicate that the margin of safety may actually be increased in subjects with elevated basal sympathetic tone; eg, those who are overweight and those with slight elevations of arterial blood pressure.