THOMPSON MEDICAL PHENYLPROPANOLAMINE STUDY BLOOD PRESSURE RESULTS

THOMPSON MEDICAL PHENYLPROPANOLAMINE STUDY BLOOD PRESSURE RESULTS show no statistically significant differences between treatment groups and placebo, the firm reported in a June 20 submission of a recently completed study of 244 patients. The subjects, evaluated over a 12-hour period, were randomized to receive either 75 mg sustained release phenylpropanolamine followed by two doses of placebo, 25 mg phenylpropanolamine t.i.d., or placebo t.i.d. "Differences in blood pressure between drug treatment groups were small and not statistically significant," the firm said. "Overall differences in pulse rate between treatment groups averaged less than" two beats per minute, the firm stated. The one "statistically reliable difference in blood pressure response attributable to drug condition" occurred with the 75 mg sustained release dosage, which "was associated with slightly higher values than the other drug treatments (mean difference from placebo of 3.65 mm Hg)," Thompson Medical reported. The firm maintained that "both the small magnitude and lack of consistency [across weight classes] of this effect indicate that it is not of clinical significance." Thompson Medical stated that changes in blood pressure, checked 11 times during the 12-hour study period, were "not related to drug treatment condition, and all fell well within the range of normal circadian variation." Subjective ratings of drug effect revealed that "the effects of the two [phenylpropanolamine] treatments were not differentiated from that of placebo treatment," the firm stated. Thompson Medical's submission presents the results from one site of a four-site trial involving a total of 864 subjects. The firm explained that the present study is an extension of previously submitted trials to examine effects of phenylpropanolamine on blood pressure, pulse, and subjective evaluation of side effects. The agency requested such additional information in a 1982 Federal Register notice. More recently, however, at a December 1983 feedback meeting with Thompson Medical and Robins, FDA recommended that a pilot study be conducted to determine the dosage level that produces adverse effects.