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  • Veterinary Cascade

The Cascade is a legislative provision in the Veterinary Medicines Regulations 2005 (VMR) that allows a veterinary surgeon to prescribe unauthorised medicines that would not otherwise be permitted.

Why would my veterinary surgeon prescribe a cascade drug for my pet?

The principle of the Cascade is that, if there is no suitable veterinary medicine authorised in the UK to treat a condition, the veterinary surgeon responsible for the animal may, in particular to avoid causing unacceptable suffering, treat the animal.

How does the veterinary surgeon decide what cascade drug to use?

In accordance with the following sequence, in descending order of priority:

A veterinary medicine authorised in the UK for use in another animal species or for a different condition in the same species.

If there is no such product, the next option is either-

A medicine authorised in the UK for human use, or

A veterinary medicinal product (VMP) not authorised in the UK but authorised in another Member State (MS) for use in any animal species (in the case of a food-producing animal the medicine must be authorised in a food producing species) in accordance with an import certificate issued by the VMD.

If there is no such product, the last option is a medicine prescribed by the veterinary surgeon responsible for treating the animal and prepared extemporaneously by a veterinary surgeon, a pharmacist or a person holding an appropriate manufacturer’s authorisation. In exceptional circumstances, medicines may be imported from Third countries through the VMD’s import scheme.

Food producing animals

Food producing animals may only be treated under the Cascade with medicines which contain pharmacologically active substances listed in the Table of Allowed Substances in Commission Regulation EU (European Union) No.37/2010, in the interest of food safety. EU Commission Regulation No. 37/2010 can be found on

A veterinary surgeon prescribing for, or administrating a medicine to, food-producing animals under the Cascade is required to specify an appropriate withdrawal period to the animal produce. When setting the withdrawal period, a veterinary surgeon must take into account known information about the use of a product on the authorised species when prescribing to another species under the Cascade. Unless the medicine indicates a withdrawal period for the species concerned, this should not be less than:

-7 days for eggs and milk

-28 days for meat from poultry and mammals

-500 degree days for meat and fish

For more information on the veterinary cascade visit https://www.gov.uk/the-cascade-prescribing-unauthorised-medicines

If you have any concerns over the medication your veterinary surgeon has prescribed for your pet please contact your veterinary surgeon immediately.