The Pressor Effect of Phenylpropanolamine-Reply

In Reply. — The argument by Drs Pentel and O'Connell states that variability in the response to PPA—especially at higher doses than used in our study— may be associated with a sharp increase in blood pressure in certain individuals. Unfortunately, this conclusion is based on an inadequate sample size. The study by Pentel et al 1 used a crossover design involving 10 healthy subjects and reported 3 (30%) of 10 cases with an increase of at least 20 mm Hg in systolic blood pressure for PPA vs placebo. Similarly, O'Connell et al 2 found such increases in 4 (40%) of 10 cases. The two-sided 95% confidence intervals for these proportions are 7% to 67% for the study by Pentel et al and 11% to 75% for the study by O'Connell et al. Thus, we are uncertain whether this large variation is a true biologic difference in the response to PPA