DO PSEUDOEPHEDRINE OR PHENYLPROPANOLAMINE IMPROVE MAXIMUM OXYGEN-UPTAKE AND TIME TO EXHAUSTION

Objective: To study the effects of over-the-counter dosages of the pur r alpha(1)-agonists pseudoephedrine (PSE) and phenylpropanolamine (PPA ) on selected parameters of exercise performance. and to establish a r ange of corresponding drug levels in the urine of the athletes who use these drugs. Design: Placebo-controlled, randomized, double-blinded, multiple-dose trial. Setting: The National Institute of Fitness and Sp ort, the Department of Family Medicine, Indiana University, and the Sp orts Medicine Lab, Department of Pathology, Indiana University, Indian apolis, Indiana. Participants: A convenience sample of 20 male cyclist s. aged 18-35, from the local cycling community. Inclusion criteria re quired cycling at least 50 miles a week, no chronic medical problems, and not taking any medications. Subjects were recruited by local ads a nd word of mouth. Intervention: Patients were randomized to one of two groups of 10 subjects. Each subject in both groups performed three se parate bicycle ergometer tests after ingestion of varying dosages of a lpha(1)-agonists. One group performed tests after receiving placebo, 0 .33 mg/kg PPA, and 0.66 mg/kg PPA, whereas the other group received pl acebo, 1 mg/kg PSE, and 2 mg/kg PSE. A minimum 1-week washout period w as required between tests. Urine for drug testing was collected 1 h be fore, immediately afterward, and the next morning after testing. Drug testing was performed by gas GC/MCD at a facility approved by the Inte rnational Olympic Committee. Main outcome measures: Maximum oxygen upt ake (Vo(2)max), time to exhaustion, urine drug levels of PSE and PPA, peak blood pressures (BPs), peak pulse, and Borg scale (rating of perc eived exertion or RPE). Main Results: In the PPA group, the 0.33-mg/kg dose resulted in insignificant changes in peak systolic BP (+5.4 mm H g, p = 0.260), peak diastolic BP (-1.6 mm Hg, p = 0.622), peak pulse ( -2.2 beats/min, p = 0.13), peak Borg (RPE = -0.10 (p = 0.823), time to exhaustion (-16.9 s, p = 0.287), and Vo(2)max (+0.50 ml/kg/min, p = 0 .71). No significant change was noted in any study variable at the 0.6 6-mg/kg PPA dose, and some effects were dissimilar to the lower PPA do se effects. Peak systolic BP increased 2.8 mm He (p = 0.617), diastoli c BP decreased 1.6 mm HE ip = 0.634), peak pulse increased 1.4 beats/m in (p = 0.504), peak Borg RPE decreased 0.80 (p = 0.210), time to exha ustion decreased 2.6 s (p = 0.861), and Vo(2)max decreased 2.92 ml/kg/ min (p = 0.14). In the 1-mg/kg PSE group, there was a significant incr ease in peak systolic BP (+10.6 mm Hg, p = 0.019). No significant chan ges occurred in peak diastolic BP (+2.4 mm Hg) p, 0.333), peak pulse ( +2.2 beats/min, p = 0.306), peak RPE (+0.2, p = 0.62), time to exhaust ion (+21.4 s, p = 0.289), and Vo(2)max (+2.29 ml/kg/min, p = 0.31). In the 2-mg/kg PSE dose trial, there were insignificant changes in peak systolic BP of +2.4 mm Hg (p = 0.559), +3.8 mm Pig in peak diastolic B P (p = 0.106), +1.6 beats/min in peak pulse (p = 0.586), -0.1 in peal; Borg RPE scales(p = 0.76). -10.4 s in time to exhaustion (p = 0.41, a nd +1.79 ml/kg/min in Vo(2)max (p = 0.43). Urine drug levels in those subjects receiving I mg/kg PSE ranged from 7-55 mu g/ml before perform ance and 30-128 mu g/ml after performance to 7-35 mu g/ml the next mor ning. Levels in those receiving 2 mg/kg ranged from 5-160 mu g/ml befo re performance and 44-200 mu g/ml after performance to 8-44 mu g/ml th e next day. In the PPA 0.33-mg/kg dose trials, the levels ranged 1-36 mu g/ml before performance and 9-50 mu g/ml after performance to <1-14 mu g/ml the next morning. In the PPA 0.66-mg/kg dose trials, the leve ls were 4-52 mu g/ml before performance. 8-80 mu g/ml after performanc e, and 6-74 mu g/ml the next day. Conclusions: We found no significant differences between trials in maximum oxygen uptake (Vo(2)max), peak or progression of Borg Scale (RPE), maximum systolic and diastolic BPs , peak pulse, or time to exhaustion among the athletes tested at the d osages studied, Urine drug levels in athletes taking one and two times the over-the-counter dosages of PPA and PSE in all cases exceeded all owable limits according to International Olympic Committee drug-testin g standards.