FEI Expands Prohibited Substances List for Competition Horses

The Federation Equestre Internationale (FEI), the governing body for international sport horse competition in eight disciplines, has approved several substances for addition to its two-part list of prohibited substances. Beginning in January of 2014, metformin and levothyroxine will join the FEI’s list of controlled substances. ACTH will join the controlled medication list, and ammonium chloride injectable, gamma-hydroxybutyrate (GHB), and gamma-butyrolactone (GBL) will be newly listed as banned substances.

Metformin is used as a treatment for type-2 diabetes in humans, where it suppresses the liver’s production of glucose. It also has the benefit of preventing damage to the blood vessels, a serious complication of diabetes.

Levothyroxine, a synthetic preparation of thyroxine, is branded as Synthroid. It is used in humans to treat thyroid hormone deficiency caused by Hashimoto’s disease and other factors like thyroid cancer. It is thought that its use in horses could enhance performance.

ACTH, or adrenocorticotropic hormone, has therapeutic value but could also affect performance. Secreted by the pituitary gland, ACTH increases the production of corticosteroids.

Ammonium chloride has an irritating action in the bronchial tubes and encourages the clearance of mucus, thus possibly enhancing performance.

GHB occurs naturally in the human central nervous system and is also found in some meats and fruits. Preparations containing GHB are used in humans to treat cataplexy (muscular collapse associated with fear or excitement) and narcolepsy, a neurological sleep disorder.

GBL, which can be synthesized from GHB, can cause a five-fold increase in growth hormone levels in humans.

Controlled and banned substances are listed by the FEI because the federation considers that they have the potential either to be used improperly, thus endangering animal welfare, or to improve athletic performance in horses.