Toxicology of substances that affect performance and behaviour: General and applied toxicology 3rd edition

he use of drugs to enhance performance has become a matter of increasing concern in recent years. However, with the advent of a greater range of pharmacologically active substances, and the possibility of psychological or financial reward, the temptation to use drugs in the pursuit of enhanced sporting performance or body image has increased.

Regulation of drugs in sport seeks to prevent the use of banned substances and techniques whilst allowing the legitimate use of therapeutic interventions for genuine medical conditions. The use of performance enhancing drugs may be accompanied by serious, even life threatening side effects.

Performance enhancing drugs may be used at the time of competition, or as a ‘training aid’ outside the competitive season, for example to increase muscle bulk. Their effect may be to increase strength or to allow a greater power output, for example by increasing oxygen delivery to tissues. Abused drugs include androgenic anabolic steroids, creatine, beta-2 agonists, beta blockers, peptide hormones and diuretics. Techniques to improve oxygen delivery include the use of high altitude training, autologous blood transfusions and the use of erythropoietin.

Successful detection of abused drugs is fundamental for regulatory programs to be successful. Such programs should include random out of season testing, rigorous sample handling protocols and reliable analytical techniques. The advent of synthetic hormones with structures similar or identical to endogenous hormones presents significant regulatory challenges. Determination of the use of proscribed substances may involve setting threshold concentrations or defining acceptable ratios of different hormones. As more sophisticated techniques of abuse develop it may become necessary for regulatory programs to use increasingly invasive sampling techniques, to determine hormone profiles for individual athletes and even to undertake challenge tests which seek to differentiate endogenous from exogenous hormone production.