Salbutamol, Pharmacogenetics and Breathing Mechanics

The Pharmacogenetic Effects of Inhaled Salbutamol on Breathing Mechanics and Cycling Performance

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.

Study Overview

• Status: Completed
• Conditions: Bronchoconstriction; Inhaled Salbutamol; Cycling Performance
• Intervention / Treatment: Drug: Placebo; Drug: Salbutamol

• Study Type: Interventional
• Enrollment (Actual): 94
• Phase: Phase 4

Contacts and Locations

Study Locations

• Canada
  • British Columbia
    • Vancouver, British Columbia, Canada, V6T 1Z1
      • Environmental Physiology Laboratory, University of British Columbia

Participation Criteria

Eligibility Criteria

• Ages Eligible for Study: 19 years to 45 years (ADULT)
• Accepts Healthy Volunteers: Yes
• Genders Eligible for Study: All

Description

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 Plan

How is the study designed?

Design Details

• Primary Purpose: BASIC_SCIENCE
• Allocation: RANDOMIZED
• Interventional Model: CROSSOVER
• Masking: DOUBLE

Number of Arms

2

Arms and Interventions

Participant Group / Arm	Intervention / Treatment
EXPERIMENTAL: 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.	Drug: Salbutamol; 60 minutes prior to the start of a 10km cycling time trial on a bike ergometer, subjects will inhale either 400ug of salbutamol 1600ug of salbutamol or 400ug of placebo in a randomly assigned manner in a single dose.; Other Names: ventolin
PLACEBO_COMPARATOR: 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.	Drug: Placebo

What is the study measuring?

Primary Outcome Measures

Outcome Measure	Measure Description	Time Frame
The effect of inhaled salbutamol on mean power output during cycling performance in female and male athletes	Athletes perform a two time trials, each on a separate day. The time trials are performed 60min after the inhalation of salbutamol or placebo.	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.
The effect of inhaled salbutamol on work of breathing (WOB) and expiratory flow limitation (EFL) in female and male athletes	EFL and WOB will be assessed with the help of an esophageal balloon and mouth pressure.	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.

Secondary Outcome Measures

Outcome Measure	Time Frame
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).

Collaborators and Investigators

• Sponsor: University of British Columbia
• Collaborators: World Anti-Doping Agency

Study record dates

Study Major Dates

• Study Start: May 1, 2013
• Primary Completion (ACTUAL): December 1, 2014
• Study Completion (ACTUAL): August 1, 2016

Study Registration Dates

• First Submitted: July 8, 2013
• First Submitted That Met QC Criteria: July 17, 2013
• First Posted (ESTIMATE): July 19, 2013

Study Record Updates

• Last Update Posted (ESTIMATE): November 2, 2016
• Last Update Submitted That Met QC Criteria: October 31, 2016
• Last Verified: October 1, 2016

More Information

Terms related to this study

• Keywords: cycling; exercise-induced bronchoconstriction (EIB); inhaled salbutamol; performance enhancing
• Additional Relevant MeSH Terms: Pathologic Processes; Respiratory Tract Diseases; Respiration Disorders; Respiratory Aspiration; Physiological Effects of Drugs; Adrenergic Agents; Neurotransmitter Agents; Molecular Mechanisms of Pharmacological Action; Autonomic Agents; Peripheral Nervous System Agents; Adrenergic Agonists; Bronchodilator Agents; Anti-Asthmatic Agents; Respiratory System Agents; Reproductive Control Agents; Adrenergic beta-2 Receptor Agonists; Adrenergic beta-Agonists; Tocolytic Agents; Albuterol
• Other Study ID Numbers: H09-01154-A009