The Effects of Inhaled Terbutaline on 3-km Running Time-Trial Performance

Abstract

Terbutaline is a prohibited drug except for athletes with a therapeutic use exemption certificate; terbutaline’s effects on endurance performance are relatively unknown. Purpose: To investigate the effects of 2 therapeutic (2 and 4 mg) inhaled doses of terbutaline on 3-km running time-trial performance. Methods: A total of 8 men (age 24.3 [2.4] y; weight 77.6 [8] kg; and height 179.5 [4.3] cm) and 8 women (age 22.4 [3] y; weight 58.6 [6] kg; and height 163 [9.2] cm) free from respiratory disease and illness provided written informed consent. Participants completed 3-km running time trials on a nonmotorized treadmill on 3 separate occasions following placebo and 2- and 4-mg inhaled terbutaline in a single-blind, repeated-measures design. Urine samples (15 min postexercise) were analyzed for terbutaline concentration. Data were analyzed using 1-way repeated-measures analysis of variance, and significance was set at P < .05 for all analyses. Results: No differences were observed for completion times (1103 [201] s, 1106 [195] s, 1098 [165] s; P = .913) for the placebo or 2- and 4-mg inhaled trials, respectively. Lactate values were higher (P = .02) after 4 mg terbutaline (10.7 [2.3] mmol·L−1) vs placebo (8.9 [1.8] mmol·L−1). Values of forced expiratory volume in the first second of expiration (FEV1) were greater after inhalation of 2 mg (5.08 [0.2]; P = .01) and 4 mg terbutaline (5.07 [0.2]; P = .02) compared with placebo (4.83 [0.5] L) postinhalation. Urinary terbutaline concentrations were mean 306 (288) ng·mL−1 and 435 (410) ng·mL−1 (P = .2) and peak 956 ng·mL−1 and 1244 ng·mL−1 after 2 and 4 mg inhaled terbutaline, respectively. No differences were observed between the male and female participants. Conclusions: Therapeutic dosing of terbutaline does not lead to an improvement in 3-km running performance despite significantly increased FEV1. The findings suggest that athletes using inhaled terbutaline at high therapeutic doses to treat asthma will not gain an ergogenic advantage during 3-km running performance.

Annual banned‐substance review – Analytical approaches in human sports drug testing

“…1 kg was determined for the habitual and the resistance training group, suggesting a considerable skeletal muscle growth. Conversely, no effect was reported concerning the endurance‐trained cohort, which matches the observations of Molphy et al, who investigated the effect of inhaled terbutaline (2 mg and 4 mg) on athletes’ 3 km time trial runs . Significantly enhanced values for the forced expiratory volume were recorded, which however did not translate into an ergogenic advantage.…”

Aerobic performance among healthy (non-asthmatic) adults using beta2-agonists: a systematic review and meta-analysis of randomised controlled trials

“…The present meta-analysis consists of 47 RCTs including 43 studies with a crossover design (16-58) of which eight studies comparing two (33,35,39,44,46,53,55,58) and one study comparing three different interventions (40) with placebo, and four studies with parallel design (59-62) (one with both acute and multiple week intervention ( 62)). The meta-analysis of aerobic performance include 60 different randomized and placebo controlled comparisons with beta2-agonists comprising 607 participants in crossover trials including 99 participants in three-way crossover trials comparing two different treatments with placebo and 27 participants in a four-way crossover comparing three different beta2-agonist treatments with placebo.…”

Prevalence of Prohibited Substance Use and Methods by Female Athletes: Evidence of Gender-Related Differences

“…This study highlighted relatively greater use of beta-2 agonists in women vs. men, with a higher use of terbutaline. The effects of beta-2 agonists on aerobic performance have been investigated in both male and female athletes after acute therapeutic inhalation of salbutamol (Koch et al, 2015 , 2016 ) and terbutaline (Molphy et al, 2019 ), with no performance change noted whatever the gender (Koch et al, 2015 , 2016 ; Molphy et al, 2019 ). However, acute salbutamol intake induced a significant increase in both anaerobic peak power and capacity in women (Le Panse et al, 2007 ), whereas only improvement in peak power was reported in men (Collomp et al, 2005 ).…”