Salbutamol, Pharmacogenetics and Breathing Mechanics

Phase 4

Completed

• Conditions: Bronchoconstriction; Inhaled Salbutamol; Cycling Performance
• Interventions: Drug: Salbutamol; Drug: Placebo

• Registration Number: NCT01903785
• Lead Sponsor: University of British Columbia

Brief Summary

Athletes using asthma medications called β2-agonists win a disproportionately high number of medals at Olympic Games. Due to a large variety in the genes that affect how individuals respond to β2-agonists, the investigators will look at variations in the genetic response to these medications by dividing athletes into high-responders and low-responders. The investigators will then compare athletic performance after the inhalation of β2-agonists to placebo. Furthermore, the investigators will analyze the effect of β2-agonists on breathing mechanics. Due to differences in their anatomy females may decrease the energy needed for breathing during high-intensity exercise to a greater extent compared to male athletes after the inhalation of β2-agonists.

Detailed Description

Not available

Study Timeline

• Study Start: 2013-05
• Study First Submitted: 2013-07-08
• Study First Submitted QC: 2013-07-17
• Study First Posted: 2013-07-19
• Primary Completion: 2014-12
• Study Completion: 2016-08
• Status Verified: 2016-10
• Last Update Submitted: 2016-10-31
• Last Update Posted: 2016-11-02

Recruitment & Eligibility

• Status: COMPLETED
• Sex: All
• Target Recruitment: 94

Inclusion Criteria

• trained, experienced cyclists
• maximal oxygen consumption of at least 50ml/kg/min or 4l/min for women; and 60ml/kg/min or 5l/min for men
• athletes with and without exercise-induced bronchoconstriction

Exclusion Criteria

• any uncontrolled heart or lung condition
• maximal oxygen consumption of less than 50ml/kg/min or 4L/min for women; and less than 60ml/kg/min or 5L/min for men
• pregnancy
• smoking

Study & Design

• Study Type: INTERVENTIONAL
• Study Design: CROSSOVER

Arm && Interventions

Group	Intervention	Description
Salbutamol	Salbutamol	400ug of salbutamol (one single inhalation) will be inhaled 60min prior to the begin of a time trial. Mean power output during the following 10km time trial will be described to 1600ug salbutamol and placebo.
Placebo	Placebo	400ug of placebo (one single inhalation) will be inhaled 60min prior to the begin of a time trial. Mean power output during the following 10km time trial will be described to 400ug and 1600ug salbutamol.

Primary Outcome Measures

Name	Time	Method
The effect of inhaled salbutamol on work of breathing (WOB) and expiratory flow limitation (EFL) in female and male athletes	WOB and EFL will be assessed during an incremental exercise test. Exercise will start at 0 Watts and will then be increased every 2.5min by 30 Watts until maximal exertion.	EFL and WOB will be assessed with the help of an esophageal balloon and mouth pressure.
The effect of inhaled salbutamol on mean power output during cycling performance in female and male athletes	Mean power output is assessed over the duration of a 10km time trial (start of time trial until completion of time trial) on a bike ergometer.	Athletes perform a two time trials, each on a separate day. The time trials are performed 60min after the inhalation of salbutamol or placebo.

Secondary Outcome Measures

Name	Time	Method
The effect of inhaled salbutamol on minute ventilation in asthmatic and non-asthmatic trained, female and male cyclists	Minute ventilation will be assessed during two 10km time trials (one time trial will be started 60min after the inhalation of salbutamol, the second time trial will be started 60min after the inhalation of placebo).

Trial Locations

Locations (1)

Environmental Physiology Laboratory, University of British Columbia; 🇨🇦 Vancouver, British Columbia, Canada