Inadvertent use of drugs in sport
Written by David Mottram, United Kingdom
Category: Sports Pharmacy

Volume 4 | Issue 1 | 2015
Volume 4 - Issue 1

The role of healthcare professionals


– Written by David Mottram, United Kingdom


In accordance with the regulations of the World Anti-Doping Code, the World Anti-Doping Agency (WADA) publishes, annually, the List of Prohibited Substances and Methods1. Athletes are subject to routine anti-doping tests for these prohibited substances and methods, with no prior notice, both within competition and out-of-competition2.


Many athletes who have recorded an Adverse Analytical Finding (AAF) arising from an anti-doping test have claimed that the presence of the prohibited substance was due to inadvertent use. Some recent examples of cases in which athletes have claimed such inadvertent use are shown in Table 1.


Athletes may take drugs for a wide variety of reasons. These include the treatment of medical conditions, social or recreational use, nutritional supplementation and for illegal performance enhancement3. With the exception of illegal performance enhancing drug use, such reasons for taking drugs could lead to the inadvertent use of substances that are included on the WADA Prohibited List.


The term ‘inadvertent’ may be defined as ‘not resulting from or achieved through deliberate planning’4. However, athletes should be aware that WADA’s principle of strict liability states that “each athlete is strictly liable for the substances found in his or her bodily specimen, and that an anti-doping rule violation occurs whenever a prohibited substance (or its metabolites or markers) is found in bodily specimen, whether or not the athlete intentionally or unintentionally used a prohibited substance or was negligent or otherwise at fault”5.


The onus to prove that use was inadvertent therefore rests with the athlete. The variability in the sanctions that were imposed on those athletes described in Table 1 reflects the degree to which the athletes were or were not able to prove their case for inadvertent use.


In this paper, the factors surrounding the inadvertent use of prohibited substances by athletes are explored. An evaluation is made of the types of prohibited substances that may be taken inadvertently, with particular regard to supplements and recreational drugs. The systems employed by the anti-doping organisations to sanction inadvertent prohibited drug use are reviewed. Finally, some thoughts on the role of Athlete Support Personnel, particularly healthcare professionals, in advising athletes on this issue are presented.



Table 2 lists some of the more common prohibited substances that may be taken inadvertently by athletes and the potential routes for their administration.


Supplements provide the primary route for the inadvertent use of prohibited substances. However, other methods of administration should not be discounted and are therefore included in the brief review, below.



The case of Alberto Contador, in 2010, raised the concern of foodstuffs being contaminated with prohibited substances such as the anabolic agent, clenbuterol. This drug has been used in countries such as China and Mexico as a growth promoter for cattle. A large number of similar cases relating to inadvertent use of clenbuterol have subsequently been reported6,7. Differentiating between the intentional use of clenbuterol or its consumption through food contamination during anti-doping testing is challenging, however, analytical procedures are being investigated8.


Additional cases involving foodstuffs contaminated with other growth promoting agents, which have resulted in an AAF during routine anti-doping tests, have been described9.


Other types of foodstuff that have the potential to produce inadvertent doping include products containing hemp, derived from Cannabis sativa. Brownies, cookies and cakes prepared with hemp could result in excretion of the metabolites of tetrahydrocannabinol within the urine10. Similarly, the consumption of poppy seeds in bread or cakes could give rise to morphine excretion within the urine.



Many of the classes of drugs that appear on the WADA Prohibited List are prescribed for the treatment of medical conditions, such as asthma, type 1 diabetes, certain cardiovascular disorders and sports injuries. Inadvertent use of these drugs, by athletes, should not occur provided the medical practitioner prescribing such drugs is conversant with and complies with the WADA regulations appertaining to Therapeutic Use Exemption (TUE)11.


In contrast, inadvertent use of prohibited stimulants, such as cathine, ephedrine and pseudoephedrine, through self-medication with over-the-counter (OTC) medicines, provides a much greater cause for concern for athletes. Athletes should therefore always seek expert advice from healthcare professionals before self-medicating for any minor medical condition such as hay fever, the common cold or cough. Another potential route for inadvertent doping is through the use of over-the-couter ‘natural’ medicines that include animal tissues containing endogenous anabolic androgenic steroids9.


It is worth noting that over-the-counter medicines do not always contain the same ingredients in each country. This was highlighted by the case of Alain Baxter, the British skier who tested positive for the prohibited drug levmethamphetamine, having used a Vicks sinus inhaler purchased in the USA during the 2002 Salt Lake City Winter Olympic Games. The equivalent Vicks product that he normally purchased in the UK did not contain this ingredient.


Recreational drugs

‘Recreational’ use of drugs is an increasingly common aspect of social behaviour in many countries. Published research concerning the extent to which athletes use recreational drugs is scarce. However, it is reasonable to assume that a proportion of athletes use drugs recreationally. Indeed, a study on self-admitted behaviour among competitive Hungarian athletes indicated that 31.7% used recreational drugs12.


The more frequently used recreational drugs, that are included in the WADA Prohibited List and may therefore result in inadvertent doping, are amphetamines, narcotics, cocaine and cannabinoids. These classes of drugs, with the possible exception of cannabinoids, have the potential to significantly enhance sport performance and are liable to be used deliberately as doping agents as well as being used in a recreational context.


With specific regard to cannabis, its use may reduce anxiety and produce a feeling of euphoria. These properties could be beneficial in alleviating the stress induced through competition, either pre- or post-event. However, cannabis smoking impairs cognition and psychomotor and exercise performance13. The balance of evidence suggests that cannabinoids, in most sports, are ergolytic rather than ergogenic14. Nonetheless, the annual statistics from WADA Accredited Laboratories show that cannabinoids is a class of drugs that is frequently analysed and reported by the laboratories (Table 3).


It is worth noting that cannabinoids are only tested in-competition, therefore, any positive results found in urine samples taken out-of-competition are not reported by laboratories. The extent of cannabis use by athletes could therefore be significantly higher than that indicated by these WADA statistics.


Some of the pharmacokinetic properties of cannabinoids may account for the high frequency of reporting by WADA laboratories. Cannabinoids accumulate in fatty tissue from where they are slowly released over extended periods of time. Complete elimination from the body may take as long as 30 days15. A further reason for the extended period of elimination for cannabinoids is that the metabolites are only partially excreted in the urine whereas most (65%) are excreted into the gastrointestinal tract from where they are re-absorbed into the body, a process that continues over a considerable period of time16. This delayed elimination is likely to be associated with recreational and therefore inadvertent use of cannabinoids by athletes.


Unsurprisingly, some athletes who have recorded an AAF for cannabinoids, have claimed that it was through the passive inhalation of cannabis smoke from other users. However, WADA regulations now state that urinary levels of tetrahydrocannabinol (Carboxy-THC) must exceed a threshold of 150ng/mL in order to trigger an AAF17, a situation which is unlikely to occur through passive inhalation.



Supplement use by high-performance athletes has been estimated to be between 65 and 95%18. In support of this estimate, some recent reports relating to the extent of supplement use by elite athletes are shown in Table 4.

The evidence shows clearly that supplements are used extensively by elite athletes, a practice that is imitated by sportsmen and sportswomen at all levels of performance. In addition to the ongoing debate as to whether it is always beneficial for athletes to use supplements in sport, one must also ask the critical question, are supplements safe to use?

Since 2003, a significant number of nutritional supplements have appeared on the market, with claims that they can produce remarkable increases in muscle growth and improved strength. In some cases, these claims were attributable to ingredients with unapproved names which have been analysed as containing anabolic steroids such as metandienone, stanazolol, oxandrolone and dehydrochloromethyltestosterone9. Supplements that contain ‘designer steroids’ have produced positive doping results with serious consequences for the athletes’ concerned25. Other supplements, advertised as fat burners or mood enhancers, may contain prohibited stimulants such as ephedrine, sibutramine or methylhexaneamine, undeclared on the product label26.


It has been reported that a significant percentage (5 to 20%) of supplements contain prohibited substances, which are present either through inadvertent contamination or through deliberate adulteration during the production process18.

When considering evidence such as that presented above, it was unsurprising to learn that, in the UK, “44% of anti-doping rule violations in 2012 were claimed to be associated with supplement usage” (personal communication with UK Anti-Doping).


It has been recommended that athletes should only use supplements after a careful cost-benefit analysis27. This advice makes perfect sense since the cost can include the significant threat of sanctions through inadvertent use of prohibited substances.



The 2015 WADA Code (Article 2.1.1) states that: “It is each Athlete’s personal duty to ensure that no prohibited substance enters his or her body. Athletes are responsible for any prohibited substance or its metabolites or markers found to be present in their samples. Accordingly, it is not necessary that intent, fault, negligence or knowing use on the athlete’s part be demonstrated in order to establish an anti-doping rule violation.”


Where an athlete claims ‘no fault or negligence’, he or she must establish how the prohibited substance entered his or her system, a difficult undertaking in the case of inadvertent use.


On the basis that prevention offers a more rational approach to this problem, athletes would benefit from expert advice and support in order to avoid inadvertent prohibited drug use.



The 2015 World Anti-Doping Code recommends a more proactive role for Athlete Support Personnel, a group which includes healthcare professionals, in the prevention of doping in sport. The inadvertent use of prohibited substances in sport is preventable in most cases. There are a number of ways in which healthcare professionals can advise and support athletes to reduce the incidence of inadvertent use of prohibited substances. These are summarised in Figure 1.



Athletes who record an AAF, arising from an anti-doping test, frequently claim that the drug had been taken inadvertently.

Inadvertent use of prohibited substances in sport may arise through drug treatment for medical conditions, taking drugs recreationally, using nutritional supplements or consuming contaminated food.

Sanctions for anti-doping rule violations are severe.

Although the potential for inadvertent use of prohibited substances is recognised by anti-doping agencies, the onus to prove inadvertent use rests with the athlete.

There are a number of ways in which healthcare professionals can advise and support athletes in order to reduce the incidence of inadvertent use of prohibited substances in sport.



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  4. Definition: ‘inadvertent’. From Accessed June 2014.
  5. Strict Liability in Anti-Doping. From Accessed January 2015.
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  8. Thevis M, Thomas A, Beuck S, Butch A, Dvorak J, Schänzer W. Does the analysis of the enantiomeric composition of clenbuterol in human urine enable the differentiation of illict clenbuterol administration from food contamination in sports drug testing? Rapid Commun Mass Spectrom 2013; 27:507-512.
  9. Geyer H, Schänzer W, Thevis M. Anabolic agents: recent strategies for their detection and protection from inadvertent doping. Br J Sports Med 2014; 48:820-826.
  10. Yonamine M, Garcia PR, de Moraes Moreau RL. Non-intentional doping in sports. Sports Med 2004; 34:697-704.
  11. Therapeutic Use Exemption regulations. From Accessed June 2014.
  12. Uvacsek M, Nepusz T, Naughton DP. Mazanov J, Ránky MZ, Pteróczi A. Self-admitted behaviour and perceived use of performance-enhancing vs psychoactive drugs among competitive athletes. Scand J Med Sci Sports 2011; 21:224-234.
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  19. 19.          Lun, V., Erdman, K.A., Fung, T.S. et al. Dietary supplementation practices in Canadian high-performance athletes. International Journal of Sport Nutrition and Exercise Metabolism 2012; 22:31-37.
  20. 20.          Rodek, J., Sekulic, D. and Kondric, M.  Dietary supplementation and doping-related factors in high level sailing. Journal of the International Society of Sports Nutrition 2012;  9:51-61.
  21. Kim, J., Kang, S., Jung, H. et al. Dietary supplementation patterns of Korean Olympic athletes participating in the Beijing 2008 Summer Olympic Games. International Journal of Sport Nutrition and Exercise Metabolism 2011;  21:166-174.
  22. Suzic Lazic, J., Dikie, N., Radivojevic, N. et al. Dietary supplements and medications in elite sport – polypharmacy or real need? Scandinavian Journal of Medicine and Science in Sports 2011; 21:260-267.
  23. Dascombe, B.J., Karunaratna, M., Carloon, J. et al. Nutritional supplementation habits and perceptions of elite athletes within a state-based sporting institute. Journal of Science and Medicine and Sport 2010; 13(2):274-280.
  24. Tscholl, P., Alonso, J.M. Dollé, G. et al. The use of drugs and nutritional supplements in top-level track and field athletes. American Journal of Sports Medicine 2010;  38: 133-140.
  25. Parr MK, Pokrywka A, Kwiatkowska, Schänzer. Ingestion of designer supplements produced positive doping cases unexpected by the athletes. Biol Sport 2011; 28:153-157.
  26. Geyer H, Braun H, Burke LM, Stear SJ, Castell LM. A-Z of nutritional supplements: dietary supplements, sports nutrition foods and ergogenic aids for health and performance: Part 22. Br J Sports Med 2011; 45:752-754.
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David R. Mottram B.Pharm., Ph.D., F.R.Pharm.S.

Emeritus Professor of Pharmacy Practice

Liverpool John Moores University

Liverpool, UK



Image via Carine06

Recent cases in which inadvertent use of prohibited drugs has been claimed.
Examples of prohibited substances that may be taken inadvertently.
Statistics from WADA Accredited Laboratories showing the classes of drug most frequently analysed and reported between 2008 and 2013. Data obtained from:
Reports on the extent of supplement use by elite athletes.
Ways in which healthcare professionals can advise and support athletes to reduce incidences of inadvertent use of prohibited substances. TUE=therapeutic use exemption, OTC=over-the-counter.


Volume 4 | Issue 1 | 2015
Volume 4 - Issue 1

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