All About Salbutamol

[Merckx index]

Salbutamol is often used if a patient reacts poorly to a blood transfusion via a nebulizer whether a asthmatic or not.

In the scenario outlined by hog, salbutamol is given during a transfusion. For a rider like Froome, the transfusion could take place under two circumstances. The first possibility is during the course of a withdrawal-transfusion cycle, in which case the rider would have excreted all the salbutamol by the time, several weeks later, that he withdrew blood again. So the transfused blood would not have had any significant amount of salbutamol in it. We can discard this possibility as having any relevance to Froome’s situation.

The second possibility is much more interesting and relevant. In this scenario, Froome would take the salbutamol while he was transfusing during the Vuelta. This has nothing to do with transfused blood having salbutamol, it’s basically just a reason why Froome might have taken far more salbutamol than the allowed amount. But it’s very interesting, because it possibly explains why Froome was so far over the limit, just this one time. He took a relatively massive dose of salbutamol because of a bad reaction to a blood transfusion.

This scenario does require that he transfused right before stage 18, though, rather than on a rest day, which I think makes it somewhat unlikely. At the earliest, he might have transfused the night before the stage, loading up his system with enough salbutamol to exceed the threshold the following afternoon when he was tested post-stage. But most of the salbutamol would have been excreted by then. I think the only way to make this scenario work is to hypothesize that Froome was still feeling the bad effects of the transfusion the following morning, before the stage, and so continued to take large doses of salbutamol.

Much like the rather absurd notion that the 'dilution factor' somehow excludes transfusion, these false appeals from authority are far from convincing.

It's not a matter of appealing to authority, the math was shown upthread. The pharmacokinetics of salbutamol are described here:

https://www.ncbi.nlm.nih.gov/pmc/articles/PMC1401185/pdf/brjclinpharm00122-0093.pdf

Note that the volume of distribution is about 150 liters, or 30 times the volume of blood. IOW, when blood containing salbutamol is transfused, the drug is diluted into a very large volume.

 

[Netserk]

Given the race situation before stage 18, I find it plausible that an emergency dose of drugs was used (it could be a cocktail related or unrelated to a blood bag). It could be a coincidence that his positive is from the day when he had a comeback, but it is for a good reason that many think of a connection to a blood bag. He certainly performed *much* better with the high level of Salbutamol than he did the day before.

 

[samhocking]

You dont transfuse raw blood though? There won't be any substances in the blood, because you remove them in the centrifuge along with the plasma surely?
What's the advantage trying to transfuse raw blood with plasma if you don't have to anyway?

 

[thehog]

Naturally it would only be a theory. It is possible Froome took his blood bag on the second rest day. Comes out and wins the ITT the following day in strong but not convincing fashion. On Stage 17 Froome begins to show adverse reaction to the transfusion and performs poorly. It wasn’t catastrophic but it wasn’t Froome. The only drug that he could use at that point to control the reaction would be Salbutamol via a nebuliser. Any of the other listed drugs to assist do not have a threshold. The reaction clears and Froome wins crushing it again on stage 18. Now he didn’t apply for a TUE, perhaps due to his unusual use for the drug following a transfusion but perhaps thought he could game the system. By all accounts before this became public Froome didn’t appear overly concerned and was planning racing early in 2018 in preparation for the Giro. His “At home with the Froome’s” podcast was of a man who had zero concerns with not racing in 2018.

 

[Clyde Puffer]

You dont transfuse raw blood though? There won't be any substances in the blood, because you remove them in the centrifuge along with the plasma surely?
What's the advantage trying to transfuse raw blood with plasma if you don't have to anyway?

Good point Sam,
I don't think that a transfusion of whole blood would be used. As a general rule, whole blood would not be used for fear of overloading the circulatory system, increasing the risk of a cardiovascular event such as heart attack or stroke. If concentrated red cells were used, then you rightly say that the plasma fraction of the blood, containing any proteins, drugs etc would be removed. Any doctor sanctioning this treatment for a fit patient should have their head examined.
Either type of transfusion would of course elevate the patient's red blood cell count and their haematocrit(packed cell volume) which presumably are regularly checked and recorded in the athlete's biological passport.

 

[King Boonen]

Beta 2 adrenergic receptor is a membrane proteins that is found in red blood cells (I'm pretty sure it's found in a large number of cell types). I don't know how well the RBC version binds salbutamol, but assuming there is none in packed red cells wouldn't be valid. Centrifuging also isn't going to remove everything. Cells are sticky and things hang around. It is going to remove a far bit but it could easily be a contributory factor.


I wondered about salbutamol tablets crushed up in a finishing bottle in an attempt to guarantee no breathing problems. Another possibility, maybe he was given someone else's bottle by mistake.

 

[Wiggo's Package]

You dont transfuse raw blood though? There won't be any substances in the blood, because you remove them in the centrifuge along with the plasma surely?
What's the advantage trying to transfuse raw blood with plasma if you don't have to anyway?

Good point Sam,
I don't think that a transfusion of whole blood would be used. As a general rule, whole blood would not be used for fear of overloading the circulatory system, increasing the risk of a cardiovascular event such as heart attack or stroke. If concentrated red cells were used, then you rightly say that the plasma fraction of the blood, containing any proteins, drugs etc would be removed. Any doctor sanctioning this treatment for a fit patient should have their head examined.
Either type of transfusion would of course elevate the patient's red blood cell count and their haematocrit(packed cell volume) which presumably are regularly checked and recorded in the athlete's biological passport.

Bio-passport is a busted flush though IIRC the UCI gave up formal prosecutions after the Krueziger debacle

If the Dawg's off-score went haywire he'd just get another be more careful in future letter from Uncle Brian

 

[gillan1969]

Re:

Beta 2 adrenergic receptor is a membrane proteins that is found in red blood cells (I'm pretty sure it's found in a large number of cell types). I don't know how well the RBC version binds salbutamol, but assuming there is none in packed red cells wouldn't be valid. Centrifuging also isn't going to remove everything. Cells are sticky and things hang around. It is going to remove a far bit but it could easily be a contributory factor.


I wondered about salbutamol tablets crushed up in a finishing bottle in an attempt to guarantee no breathing problems. Another possibility, maybe he was given someone else's bottle by mistake.

indeed...the explanation may be something like this...did Kelly not get poppoed for the amphetamines in his soignieur's urine when they switched them for the control (Paris-Tours)???

 

[samhocking]

Re:

Beta 2 adrenergic receptor is a membrane proteins that is found in red blood cells (I'm pretty sure it's found in a large number of cell types). I don't know how well the RBC version binds salbutamol, but assuming there is none in packed red cells wouldn't be valid. Centrifuging also isn't going to remove everything. Cells are sticky and things hang around. It is going to remove a far bit but it could easily be a contributory factor.


I wondered about salbutamol tablets crushed up in a finishing bottle in an attempt to guarantee no breathing problems. Another possibility, maybe he was given someone else's bottle by mistake.

Yep, I don't know the level of attachment, but 1 litre diluted into 5 litres nearly 24 hours before giving the AAF along with whatever the delay was between taking salbutomol and withdrawing blood at the time and the storing the red blood cells wouldn't explain the reading.
I guess if Froome suffered a reaction to a transfusion the night before stage 17 and took nebulised salbutomol for a reaction, I guess there's a chance the doctors simply didn't know how much he took via a nebuliser. But to still have a reading of 2000 what would be perhaps 15-20 hours later with a half life of 4-5 hours or whatever would suggest a reading of 16000 unless half life is not linear, but exponentially falling at less than half life at high dosages. Of course he might take multiple puffs in a nebuliser throughout the night I guess maintaining his high salbutomol level, but seems a high risk, sloppy error-prone strategy as race leader. I'm sure if he's been blood doping before they would not have taken such risks, although I guess reaction to transfusions is not contants either, but it's getting more far-fetched to explain something that can be explained more simply. Who knows?

 

[King Boonen]

I still don't understand why people are trying to discredit a blood bag by showing it likely couldn't contribute all of the salbutamol. As if it's an all or nothing possibility.

 

[samhocking]

I think it's just unlikely the doctors withdrew blood at the same time they had just given him a huge dose of salbutomol and enough of it remains after having plasma removed and still with a high reading the next day after transfusion back again given its half life. Hogs nebulizer emergency for a bad reaction of course can explain it, but the nebulized dose would have to be pretty big. Could you function that evening, sleep well and perform so well the next day if you body has just reacted like that? I don't know, but when we're almost looking towards things we don't have a clue happened to explain the little we do know happened, it can't hold much water yet.

 

[Merckx index]

Re:

You dont transfuse raw blood though? There won't be any substances in the blood, because you remove them in the centrifuge along with the plasma surely?
What's the advantage trying to transfuse raw blood with plasma if you don't have to anyway?

Riders transfuse whole blood when they can’t afford a centrifuge. Since whole blood can’t be stored refrigerated more than a few weeks, they have to undergo regular withdrawal-transfusion cycles throughout the season, when they in effect use their body to store the blood. After a blood bag has been stored a few weeks, the rider withdraws fresh blood, and replaces it with the stored blood.

I wouldn’t think an elite rider like Froome would do this, but in any case it doesn’t matter, as the transfusion scenario has been thoroughly debunked.

I don't think that a transfusion of whole blood would be used. As a general rule, whole blood would not be used for fear of overloading the circulatory system, increasing the risk of a cardiovascular event such as heart attack or stroke.

Transfusion was originally done with whole blood, and still is in some cases, for example, if there has been massive bleeding, or when one uses one’s own blood. It’s also commonly used in third world countries, which don’t have the resources to separate plasma from cells. There’s nothing wrong with it, except that it can only be stored for relatively short periods of time, and because most people who need transfusions don’t need everything in the blood.

Beta 2 adrenergic receptor is a membrane proteins that is found in red blood cells (I'm pretty sure it's found in a large number of cell types). I don't know how well the RBC version binds salbutamol, but assuming there is none in packed red cells wouldn't be valid. Centrifuging also isn't going to remove everything. Cells are sticky and things hang around. It is going to remove a far bit but it could easily be a contributory factor.

No, there isn’t going to be enough binding to cells to make a difference. Cell surface receptors typically bind only a small % of the amount of ligand in the solution surrounding them (this assumption is critical to studies determining key parameters like Kd and Bmax), and as has already been pointed out, the entire amount of salbutamol present in the volume of blood that might be withdrawn for later transfusion isn’t nearly enough to account for a high urinary level.

Consider this study, which found a peak concentration in the blood of 10-20 ng/ml, or 10 – 20 ug/l, after an oral dose of 4 mg:

https://link.springer.com/article/10.1007/BF02456001

So even if the entire amount of drug attached to the red cells, a liter’s worth of cells would still contain far less salubutamol than is present in a single puff.

And how much of this tiny amount would actually be bound to the red cells? To get a rough idea, the first paper linked below reported a b2-adrenergic receptor density of about 4 femtomoles per mg of protein. A femtomole is 10 (-15) mole, which corresponds to about 1 picogram, or 10 (-12) grams, of salbutamol/mg. A red cell has a protein mass of roughly 30 pg, and there are about 5 million per microliter, so the total amount of salbutamol bound at saturation would be about 150 ng in cells isolated from one liter of blood. That figure could be multiplied several times, because the 4 fm/mg value is specific receptor binding. There would probably be several times or more as much non-specific binding. But at most, there would be a few ug salbutamol bound to the red cells.

http://sci-hub.la/10.1016/0006-2952(84)90019-4
https://www.sigmaaldrich.com/life-science/metabolomics/enzyme-explorer/learning-center/plasma-blood-protein/blood-basics.html
http://onlinelibrary.wiley.com/doi/10.1002/cyto.a.22277/pdf

I still don't understand why people are trying to discredit a blood bag by showing it likely couldn't contribute all of the salbutamol. As if it's an all or nothing possibility.

Because it basically is a nothing possibility.

I wondered about salbutamol tablets crushed up in a finishing bottle in an attempt to guarantee no breathing problems. Another possibility, maybe he was given someone else's bottle by mistake.

How is salbutamol taken that way going to get to the lungs?

 

[thehog]

Re:

I still don't understand why people are trying to discredit a blood bag by showing it likely couldn't contribute all of the salbutamol. As if it's an all or nothing possibility.

Agree, rather than one single action it appears the mistake was a combination of events and timing which lead to his hyper-reading of Salbutamol.

 

[King Boonen]

Re: Re:

Beta 2 adrenergic receptor is a membrane proteins that is found in red blood cells (I'm pretty sure it's found in a large number of cell types). I don't know how well the RBC version binds salbutamol, but assuming there is none in packed red cells wouldn't be valid. Centrifuging also isn't going to remove everything. Cells are sticky and things hang around. It is going to remove a far bit but it could easily be a contributory factor.

No, there isn’t going to be enough binding to cells to make a difference. Cell surface receptors typically bind only a small % of the amount of ligand in the solution surrounding them, and as has already been pointed out, the entire amount of salbutamol present in the volume of blood that might be withdrawn for later transfusion isn’t nearly enough to account for a high urinary level.

Consider this study, which found a peak concentration in the blood of 10-20 ng/ml, or 10 – 20 ug/l, after an oral dose of 4 mg:

https://link.springer.com/article/10.1007/BF02456001

So even if the entire amount of drug attached to the red cells, a liter’s worth of cells would still contain far less salubutamol than is present in a single puff.

And this paper reported a receptor density of about 4 femtomoles per mg. A femtomole is 10 (-15) mole, which corresponds to about 1 picogram, or 10 (-12) grams, of salbutamol/mg. of red cells. A red cell is about 33 pg, and there are about 5 million per cc, so the total amount of salbutamol bound at saturation would be about 0.16 ng in cells isolated from one liter of blood.

http://sci-hub.la/10.1016/0006-2952(84)90019-4

Again, you're making an assumption that any salbutamol from a blood bag needs to have a large contribution. This isn't the case, it just needs to add enough that the same at the end is above the limit. Even if everything from the bag is metabolised it still adds to the total as it reduces the the amount metabolised through inhaled means. No one is claiming a blood bag is the only or largest source of salbutamol, just that it could be a contributory factor. I don't think anyone is even claiming that a blood bag alone could trip the threshold. This contribution would be alone with some of the following:

Overuse of inhaler
Use of oral Salbutamol
use of nebuliser
high conc. due to high specific gravity

Blood bag might be small, but it could still contribute. Or it might not.

I still don't understand why people are trying to discredit a blood bag by showing it likely couldn't contribute all of the salbutamol. As if it's an all or nothing possibility.

Because it basically is a nothing possibility.

I still don't see this. See above.

I wondered about salbutamol tablets crushed up in a finishing bottle in an attempt to guarantee no breathing problems. Another possibility, maybe he was given someone else's bottle by mistake.

How is salbutamol taken that way going to get to the lungs?

[/quote]

Are you asking how Salbutamol can be ingested orally, absorbed into the blood and then blood makes it's way to the lungs? I'm afraid I don't know the exact pharmacokinetics (I know it's intestinal absorption from a gamma scintigraphy study I was involved in) and peak plasma is 1-3 hours after dose but that's it. I'm sure if you really want to know you can find it on Pubmed, although the paper might be too old to be found online.

 

[samhocking]

MI is referring to the amount that could add to Froome's urine level would be very negligible and not enough to take him from perhaps a calculated nebulizer for a blood transfusion reaction and leave you with 2000 15-20 hours later even in addition to normal increased inhaler use. Of course we are guessing at a nebulizer, we are guessing a blood reaction happening, we are guessing at everything, even having to include that someone made a mistake in their calculations 3 times, to not even realise what would happen after the stage, but can be easily explained very simply as some studies have found. Time will tell.

 

[Merckx index]

Re: Re:

Again, you're making an assumption that any salbutamol from a blood bag needs to have a large contribution.

No, I'm not, I did very early in this thread entertain that possibility, but after I familiarized myself with the pharmacokinetics, I saw that it couldn't even have a significant contribution. Probably < 1%, certainly < 5%. It's a complete non-starter. I don't know how this can be made any clearer. Again, the volume of distribution, which is in effect a dilution factor, is > 100 liters. In the study I just cited, following a 4 mg dose, only about 2.5% of the salbutamol was found in the entire 5 liter volume of blood; most of it goes into the extravascular spaces. That means that if you have a urine level indicative of taking several mg, to get that from transfusing a liter of blood (which would be a very large transfusion), you would need to take several hundred mg. Even to make a significant impact on the level, say > 10%, you would probably need at least 40-50 mg, and 10% really isn't going to be much of a factor.

Are you asking how Salbutamol can be ingested orally, absorbed into the blood and then blood makes it's way to the lungs? I'm afraid I don't know the exact pharmacokinetics (I know it's intestinal absorption from a gamma scintigraphy study I was involved in) and peak plasma is 1-3 hours after dose but that's it. I'm sure if you really want to know you can find it on Pubmed, although the paper might be too old to be found online.

Well, here's a study:

http://sci-hub.la/https://www.ncbi.nlm.nih.gov/pubmed/1745854

There was no effect of a 4 mg oral dose on bronchodilation. They had to use an 8 mg dose to see an effect. So taking it orally is apparently a very inefficient way to get relief, and for a rider who has to worry about his urine levels, it would make no sense at all to take it this way, even beyond the fact that oral doses aren't permitted, and trip the enantiomers test.

 

[King Boonen]

Re: Re:

Again, you're making an assumption that any salbutamol from a blood bag needs to have a large contribution.

No, I'm not, I did very early in this thread entertain that possibility, but after I familiarized myself with the pharmacokinetics, I saw that it couldn't even have a significant contribution. Probably < 1%, certainly < 5%. It's a complete non-starter. I don't know how this can be made any clearer. Again, the volume of distribution, which is in effect a dilution factor, is > 100 liters. In the study I just cited, following a 4 mg dose, only about 2.5% of the salbutamol was found in the entire 5 liter volume of blood; most of it goes into the extravascular spaces. That means that if you have a urine level indicative of taking several mg, to get that from transfusing a liter of blood (which would be a very large transfusion), you would need to take several hundred mg. Even to make a significant impact on the level, say > 10%, you would probably need at least 40-50 mg, and 10% really isn't going to be much of a factor.

I wouldn't call 5-10% insignificant to the final reading and, if we are assuming that it is being used for doping which would necessitate a very high dose I don't think 40-50mg is unreasonable. 24mg over 24 hours certainly isn't unheard of for oral dose treatment regimes. Again, it's not going to explain the very high reading by itself, but it could certainly be a contributory factor to that high number.

Are you asking how Salbutamol can be ingested orally, absorbed into the blood and then blood makes it's way to the lungs? I'm afraid I don't know the exact pharmacokinetics (I know it's intestinal absorption from a gamma scintigraphy study I was involved in) and peak plasma is 1-3 hours after dose but that's it. I'm sure if you really want to know you can find it on Pubmed, although the paper might be too old to be found online.

Well, here's a study:

http://sci-hub.la/https://www.ncbi.nlm.nih.gov/pubmed/1745854

There was no effect of a 4 mg oral dose on bronchodilation. They had to use an 8 mg dose to see an effect. So taking it orally is apparently a very inefficient way to get relief, and for a rider who has to worry about his urine levels, it would make no sense at all to take it this way, even beyond the fact that oral doses aren't permitted, and trip the enantiomers test.

So you'd found a paper that shows it gets to the lungs. If that's the case why did you ask me?

 

[samhocking]

So if we can explain Froome going 10% over Sky's caluclations with a 50mg forgotten about / unrecorded high dose taken just before withdrawing blood outside La Vuelta at some point, ignore the half life between transfusion and urine sample being given, Sky messed up a calculation again somewhere by 90% somewhere else. The blood transfusion, unless he took several hundred mg just before withdrawing still needs explaining beyond a transfusion during the race itself. Clearly the blood transfusion theory doesn't explain tripping the threshold anyway. At best Froome's reading should be around 1100, not 2000 assuming they got their other calculations correct for increased oral intake while racing La Vuelta?

 

[King Boonen]

I'm unsure why you are asking a question that is answered in the first post above yours and, I'm assuming, the one your question is in response to?

For reference:

Again, it's not going to explain the very high reading by itself, but it could certainly be a contributory factor to that high number.

 

[samhocking]

We all agree then, which is not how you appear to be answering MI. sorry, maybe I read wrong? Happy to go with 10% from a blood transfusion and we can now get back to finding the other 90% that sees a urine amount of 2000. What did Sky miscalculate by a further 90% after the alleged transfusion?

 

[King Boonen]

Re:

We all agree then, which is not how you appear to be answering MI. sorry, maybe I read wrong? Happy to go with 10% from a blood transfusion and we can now get back to finding the other 90% that sees a urine amount of 2000.

Then the conversation must be getting tangled. Yes, I think we all agree in part. A transfusion cannot explain the total reading unless he took an enormous dose, but dismissing it completely as a factor is wrong. Add in some/all of a specific gravity calibration, overuse of inhaler, possible oral supplementation etc. and we might have some idea about how it happened.

It's very possible a transfusion wasn't involved. It's also possible that even if it was it wouldn't have tripped the test alone. I'm just pointing out it can't be completely dismissed from being a factor.

 

[hazaran]

I don't see what we are gaining from speculating that .1% of the dose is from some mysterious blood bag. Much more of the dose is down to when Froome stopped to take a piss, which we haven't clarified yet either.

Meanwhile, Dawg has already logged 1200 km for the year: https://www.strava.com/pros/7491815#interval?interval=201801&interval_type=week&chart_type=miles&year_offset=0

Not exactly training like someone who has a big vacation ahead of him, which I suppose means either this is over very soon or will drag on for a year at least

 

[TheSpud]

Salbutamol is often used if a patient reacts poorly to a blood transfusion via a nebulizer whether a asthmatic or not.

The second possibility is much more interesting and relevant. In this scenario, Froome would take the salbutamol while he was transfusing during the Vuelta. This has nothing to do with transfused blood having salbutamol, it’s basically just a reason why Froome might have taken far more salbutamol than the allowed amount. But it’s very interesting, because it possibly explains why Froome was so far over the limit, just this one time. He took a relatively massive dose of salbutamol because of a bad reaction to a blood transfusion.

This scenario does require that he transfused right before stage 18, though, rather than on a rest day, which I think makes it somewhat unlikely. At the earliest, he might have transfused the night before the stage, loading up his system with enough salbutamol to exceed the threshold the following afternoon when he was tested post-stage. But most of the salbutamol would have been excreted by then. I think the only way to make this scenario work is to hypothesize that Froome was still feeling the bad effects of the transfusion the following morning, before the stage, and so continued to take large doses of salbutamol.

Are you suggesting he took the Salbutamol during the transfusion to prevent a reaction? The scenario Hog posted using Salbutamol was as a result of anaphylaxis or severe allergic reaction. I'd imagine that if there was such a reaction it would be very soon after starting any transfusion, potentially life threatening, and the immediate action would be to get an adrenaline shot in to him asap. If that happened I'd be very surprised if he was anywhere near a bike so soon afterwards - I think he'd be counting his lucky stars that he was still alive. The Salbutamol nebuliser was stated as 'if necessary' - probably to solve any shortness of breath caused. I'd be very surprised if such a reaction was delayed by up to 24 hours after an earlier blood bag.

 

[TheSpud]

Re:

We all agree then, which is not how you appear to be answering MI. sorry, maybe I read wrong? Happy to go with 10% from a blood transfusion and we can now get back to finding the other 90% that sees a urine amount of 2000. What did Sky miscalculate by a further 90% after the alleged transfusion?

So that means we need to find the remaining 1800. Actually only the remaining 601, since anything under 1200 doesnt get reported.

 

[movingtarget]

"It is a riddle, wrapped in a mystery, inside an enigma; but perhaps there is a key." I agree with Winston.