Medicines legislation & passports

These are medicines licensed for use in the horse that are authorised for use in the food chain and are listed in table 1 of EC 37/2010.

The ability to use these medicines is usually contained in the summary of product characteristics (SPC or 'data sheet') included as a package insert or via the VMD Product Information database.

There are substances (e.g. some anaesthetic agents like ketamine and isoflurane, some antimicrobials like ceftiofur, some non-steroidal anti-inflammatories (NSAIDs) like carprofen and some substances used in breeding management like cloprostenol) that are 'allowed' in the European Regulation but which have UK marketing authorisations excluding their use in food-producing horses and requiring the horse to be declared not for human consumption. When there is a difference between the European Regulation and the UK Marketing Authorisation such substances can be used in food-producing horses provided that:

• the prescribing cascade is followed.
• a minimum meat withholding time of 28 days is set and a record is made in the passport (although this is at the discretion of the veterinary surgeon).

There is a requirement for owners to maintain a medicines record if horses are not signed out of the food chain in their passport. This can be recorded in the passport or in a separate document.

It is the responsibility of veterinary surgeons to inform owners of the likely withdrawal period although there are medicine for which no maximum residue limits (MRLs) are required (e.g. detomidine, butorphanol, ketoprofen, lidocaine, dembrexine, deslorelin).

These are medicines licensed for use in other species that are authorised for use in the food chain and are listed in table 1 of EC 37/2010.

They are used under the prescribing cascade when no suitable medicine is licensed for the use in the horse.

There is a requirement for owners to maintain a medicines record if horses are not signed out of the food chain in their passport. This can be recorded in the passport or in a separate document.

It is the responsibility of veterinary surgeons to inform owners of the likely withdrawal period in such cases although there are medicine for which no maximum reside limits (MRLs) are required (e.g. detomidine, butorphanol, ketoprofen, lidocaine, dembrexine, deslorelin).

This list includes medicines that do not have marketing authorisations for use in food producing horses, but that can be administered to horses that are classified as food producing animals (passport section II not signed) provided that:

• the prescribing cascade is followed.
• their use is followed by a 6-month withdrawal period before the animal can enter the food chain.
• their use must be recorded in the horse's passport by the veterinary surgeon.

This list includes acetylpromazine, diazepam, dobutamine, morphine, pethidine, sevoflurane, bupivacaine, triamcinolone, sucralfate, dantrolene, azithromycin and rifampicin. 

You can find more information on withdrawal periods under the horses subheading under the guidance page: The cascade: prescribing unauthorised medicines - GOV.UK (www.gov.uk). 

This also includes guidance on setting withdrawal period for both GB and NI. For Gb, substances with an MRL are listed in the GB MRL Register.

The full list (122/2013) can be accessed online

Drugs not listed in the 'allowed' list (table 1 of EC 37/2010) or the 'essentials' list (EC 122/2013) must not be used in horses classified as food producing animals.

These include those drugs previously listed in Annex IV and now listed in Table 2 of EC 37/2010 (such as metronidazole and chloramphenicol including ocular medication) and those for which maximum residue limits (MRLs) have not been determined (e.g. pergolide, phenylbutazone and suxibuzone).

If no alternative exists for the treatment of these horses then they must be immediately signed out of the food chain.