By Travis DeGraff

Terbutaline the Less Discussed PED

Oral albuterol, a popular beta 2-agonist, has been shown to increase strength, and overall performance.  Terbutaline is a lesser know beta 2-agonist that unlike albuterol, seems to work sufficiently when inhaled, vs. an oral tablet.  For example, in the study I’m about to outline they indicated that previous research has shown that 2 mg’s of inhaled terbutaline, has an area under the curve (AUC) equal to that of a 10 mg oral dose of terbutaline.  

Personally, until now I had never heard of anyone using terbutaline for ergogenic or performance purposes but it is a banned substance by the World Anti-doping Agency (WADA). WADA is constantly fighting the battle in which athletes truly need beta 2-agonists for things like asthma vs. there abuse for performance enhancement. For this reason they conducted this study in order to determine if an inhaler based delivery of terbutaline (Bricanyl®) could enhance athlete performance [Ref 1].

The participants on paper looked to be quite athletic. The 9 of them averaged 24 years of age and were involved in some form of endurance and weight training an average of 10 hours per week.  There was also a placebo group (themselves) 16 days earlier/later randomly.  The study protocol is outlined in this image (including the dose in the caption):

terbutaline for performance

The strength measurement was the portion of the study where they used maximal voluntary isometric contracts.  This is basically a single rep leg extension where they have a short static hold of 3 to 4 seconds in the flex position.  They did 3 or 4 sets of this to determine the maximal strength.  Peak power was calculated by measuring 5 seconds of the highest power output during the wingate test (which is a sprint on a stationary bike with increasing levels of tension).  And mean Power was determined as an average power throughout the 30 second cycle sprint.  During the 60 minute break several blood samples were taken to measure glucose, lactate, and  K+ (a muscle fatigue indicator).

Terbutaline a Mild Performance Enhancer

My expectation from a study like this would be that the 100 kilometer time-trial perfomance would have increased by the most (vs. strength and power output).  However the time-trial performance was no better with terbutaline, than it was without (placebo).  More interestingly for the purposes of those of us who like to lift weights, was the increase in strength.  While it was not an enormous increase (keep in mind this is an single dose acute study), they saw an increase in strength of 8.4% (+-3%) vs. placebo.  This is mild, but at least notable (and statistically significant).

terbutaline strength

Both wingate peak and mean power increased as well, but to an even lesser degree (2.2, and 3.3%).  The 30 puffs of the terbutaline inhaler that the subjects took increased blood levels of the drug to 23.6 ± 1.1 ng ml−1.  The authors point out that this is 4 times higher than a previous study observed after subjects were given 10 mg’s of oral terbutaline.  Meaning the inhaler worked even better (which is the opposite of albuterol for example).  7 out of the 9 subjects did experience side effects, which were summarized as an increase in heart rate and shaky hands.

Practical Application of Terbutaline

Realistically if you are looking for a workout boost it’s unlikely that you will reach for a terbutaline inhaler.  Especially since these men were absent of other legal non-prescription stimulants such as caffeine (where a  similar or better effect may be observed).  Still this is interesting as it shows us that this particular beta 2-agonist can be administered with an inhaler and still produce positive performance enhancements (unlike the more popular albuterol).


 

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