Salbutamol, Froome & Pharmacokinetics

At Cycloform we are cycling fans. We’re not like football fans who live in blissful ignorance regarding doping, we accept that incredible often means not-credible. We watch riders do amazing things, lighting up stages of Grand Tours, in the moment we love it!

In the cold light of day some of us put our cynics hat back on and become obsessed by comparing VAM throughout the decades and brand anyone climbing at the same speed as Marco Pantani or Lance a cheat. Forgetting the multitude of variables that exist in a racing situation and decades of product and training development.

When Alberto Contador tested positive for Clenbuterol, it was tempting to see everything he did as tainted. The fact that he is a fantastic racer (with or without the beef steak) is difficult to rejoice in when you know that a substance which should simply not be in a riders urine sample turns up. With UCI’s strict liability in play it was his job to prove how this performance enhancing drug got into his wee wee.

So, should we treat Chris Froome in the same way? I’m not writing this blog to defend Chris Froome. But it is somewhat disgruntling when the BBC 6 O’Clock News run the headline that Froome has ‘Failed a Drugs Test’. This is on the face very true, but my worry is that to the lay person, Froome is now in the same camp as Marco and the Texan.

Chris Froome has exercise induced asthma. This is well documented. One could say that this is very convenient, enabling him to take drugs. However we don’t think it’s fishy when footballers hurt their knees, why then in the toughest of all endurance sports do we think it’s strange that there is a disproportionate amount of poorly lungs? Is it cheating to take medication to treat an illness? Should people who suffer depression be excluded from professional sport because they take medication to treat this?

Asthma causes narrowing of the airways in the lungs (bronchospasm), restricting the flow of oxygen in and carbon dioxide out of the lungs. Obviously this is important.

Salbutamol is a short acting beta2 agonist, it is a common drug for the treatment of asthma. Froome himself was captured taking this drug back in 2014 at the Dauphine. Anyone who did any sport at school would have seen someone with a ‘Blue Puffer.’ When taken as an inhaled powder (as in the blue puffer) it simply acts to cause widening of the airways by binding to the beta2 adrenoceptors (bronchodilation). Our own hormones could produce this affect, but the pathological process of narrowing caused by asthma is rectified in this instance by the medication.

Exhibit 1. Salbutamol Inhaler AKA 'The Blue Puffer'

Exhibit 1. Salbutamol Inhaler AKA 'The Blue Puffer'

Salbutamol does have other affects on the wider body, it cause relaxation of the smooth muscles of the uterus (not that useful in a male cyclist – in a grand tour), opening up of blood vessels and more relevantly the breakdown of glycogen in muscle to glucose (glycogenolysis) – energy! This is an important part of the ‘Fight-or-flight response’.

I am unclear what the performance enhancing affect of Salbutamol is. Especially when taken through a ‘puffer’. WADA do test for it and we all know that Froome’s wee wee had too much in it.

Lets not forget. Froome is allowed Salbutamol in his wee wee; so he should be. Do we want to stop all asthmatics from engaging in sport… or those suffering depression… diabetes… epilepsy… HIV?

Contador had no reason for Clenbuterol to be in him. Froome has to regulate his dose, but he can take it.

Froome gets to control what dosage of Salbutamol he takes. But does he get to control how much is in his wee wee? Does what you put in automatically directly relate to what comes out?

The answer to this is no. Many things affect the way that your body deals with a drug (metabolises) and then gets rid of it (excretion). The study of what your body does to a drug is Pharmacokinetics.

After taking salbutamol through a ‘puffer’, between 10 and 20% of the dose reaches the lower airways. The remainder is retained in the puffer itself or is deposited in the throat from where it is swallowed. The fraction deposited in the airways is absorbed into the lung tissues and blood supply.

On reaching the blood it circulates around the body, goes to the liver, is broken down and then is excreted via the wee wee. The swallowed portion of an inhaled dose is absorbed from the gastrointestinal tract and undergoes considerable breaking down by the liver. Again it all ends up in the wee wee. Almost all of a dose of salbutamol given is gotten rid of within 72 hours. It doesn’t hang around, but you can’t say that the speed in which it comes out is predictable.

If you then take into account that anything that affects the gut, the liver, the kidneys (because they make wee) or the inhalation technique, we can see that this is not a simple case. Froome has no control over any of this stuff. As for research looking into the affects of a Grand Tour cyclist and their metabolism and excretion of inhaled salbutamol… I’ve not looked. But the study won’t exist.

The reason for me writing this blog was simple. This is not a simple case. It is not the same as Lance or Burt. Even if he ends up getting sanctioned, this might simply be because the science to explain this case isn’t out there. The secondary benefit to me writing this blog cannot be underestimated either. I got to write wee fourteen times and you read every single one of them!

Thanks for reading!



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