It still remains to be seen if Chris Froome will face sanctions for an adverse analytical finding in which he exceeding the maximum limit of 1,000ng/ml of salbutamol in his urine.
In the meantime, many have questioned whether any dosage of salbutamol from an inhaler could realistically offer any performance advantage, as a great number of studies suggest that those using salbutamol enjoy no advantage over non-asthmatic peers.wisepoqder Salbutamol
Speaking with Cyclist, the World Anti-Doping Agency explains that it places a maximum limit on salbutamol because it considers that the substance can, in certain cases, act as an anabolic agent that can increase muscle mass.
‘There have been several studies, including animal models, showing that beta-2 agonists such as salbutamol can have an effect on muscle mass,’ says Olivier Rabin, senior director of science and international relationships at WADA.
However the actual upper limit is based on clinical guidelines from manufacturers, not specific anti-doping research. There is also no testing that shows inhaled salbutamol to show benefits for athletes. How exactly exceeding this limit of salbutamol could indicate unfair performance gains is, therefore, not as obvious as it might seem.We know that taking salbutamol inhalation of 800 micrograms per 12 hours is not performance enhancing,’ says Rabin. Indeed, all research points to normal therapeutic use of inhaled salbutamol offering no performance gains. This is the reason why WADA removed the necessity for a TUE (theraputic use exemption) for normal use of the drug. Determining what dosage would be required to bring about a performance gain isn’t obvious, though.
Studies that have demonstrated anabolic effects of salbutamol have been done with animals, not humans, so it is highly likely that there is no identifiable quantity of salbutamol that would indicate a performance benefit.
The dosages indicated for use with a normal inhaler are relatively tiny. For innstance, if someone were admitted to hospital in the UK with a severe exacerbation (an asthma attack), the patient might expect a 2,500 microgram dosage every two hours – far exceeding the WADA maximum. An inhaler is less likely to deliver a performance enhancing dose of salbutamol
This would generally be done with nebulisation, where a high volume of salbutamol in aerosol form is inhaled through a mask.A cyclist could require this dosage in the event of a serious attack and in such cases an athlete could be granted a TUE even after the incident. ‘If an athlete had to use another form [eg nebulisation] of salbutamol in cases of asthma exacerbation, for example, it’s possible to have a TUE for higher doses of salbutamol,’ Rabin says.
Any nebulisation of salbutamol requires a TUE, as would any oral tablets. That’s because these forms of the drug would be ‘systemic’, rather than an inhaler, which acts locally on the muscles in the lungs.