The cascade: prescribe a veterinary medicine for another use

How a vet can use the cascade to prescribe a medicine that has not been specifically authorised for the relevant purpose.

This guidance was withdrawn on

The Veterinary Medicines Regulations allow the prescribing of veterinary medicines for a use other than their authorised use. This is known as the cascade.

When deciding what medicine to prescribe under the cascade you should follow the order of consideration below:

  • a veterinary medicine authorised in the UK for the same condition in another animal species or for another condition in the same animal species

Then either:

  • a medicine authorised in the UK for human use


  • a veterinary medicine not authorised in the UK but authorised in another European country for use in any animal species and in accordance with an import certificate issued by the VMD

For detailed guidance see Veterinary Medicines Guidance Note 5 - Import Certificate Scheme.

If there is no such product, you can:

  • use a medicine prescribed by the vet responsible for treating the animal and prepared especially on this occasion (known as an extemporaneous preparation or special) by a vet, a pharmacist or a person holding an appropriate manufacturer’s authorisation
  • (under exceptional circumstances) import medicines from non-EU countries in accordance with an import certificate issued by the VMD

Medicines allowed for food-producing animals

When treating food-producing animals (cows, pigs etc) you must follow the table of allowed substances in Commission Regulation EU No 37/2010.

Withdrawal periods for animal produce

When prescribing, or administering a medicine to a food-producing animal under the cascade, you must specify a minimum length of time after treatment before people can eat the animal or its produce ( the withdrawal period). In setting the withdrawal period , you must take into account what is known about the use of the product on the authorised species.

Published 28 October 2014