The changes are summarised here and below:
Two new Controlled Medication substances have been added to the List for 2014: Metformin, a potent but legitimate oral anti-diabetic drug with a potential welfare risk; and Levothyroxine, an exogenous thyroid hormone replacement that could enhance performance;
Adrenocortico-trophic hormone (ACTH), currently classified as a Banned Substance, will be moved to the Controlled Medication section of the 2014 List due to its therapeutic value in equine medicine;
Three previously unlisted substances – Ammonium Chloride injectable, Gamma-Butyrolactone (GBL) and Gamma-Hydroxybutyrate (GHB) – will be added to the Banned Substances section of the 2014 List, as they are considered to have a potential for abuse, or to improve athletic performance.
The changes to the FEI Equine Prohibited Substances List are also accessible on the FEI Clean Sport webpage. The FEI Equine Prohibited Substances Database will be amended and the complete 2014 Equine Prohibited Substances List will be made available on the Clean Sport website prior to 1 January 2014.
In accordance with FEI Rules, all changes to the List are published 90 days in advance in order to allow National Federations, athletes and veterinarians sufficient time to familiarise themselves with the revised List prior to implementation.
Source FEI Press release