The British Small Animal Veterinary Association recognises that the “Cascade” provides a rational balance between the legislative requirement for veterinary surgeons to prescribe and use authorised veterinary medicines when available, and the application of professional judgement to prescribe other medicines when they are not.

The BSAVA support the continued use of the Cascade because the current range of licensed products does not enable veterinary surgeons to effectively treat the wide range of conditions in all the species commonly encountered in small animal practice. Restriction in the use of drugs through the Cascade would lead to the inability to treat a wide range of diseases, particularly in species for which there are few licensed medicines, and consequent animal welfare issues.

The responsible use of veterinary medicines for therapeutic and prophylactic purposes is one of the major skills of a veterinary surgeon and crucial to animal welfare and the maintenance of public health. The Cascade is a risk based decision-tree to help veterinary surgeons decide which product to use when there is no authorised veterinary medicine available.

Veterinary surgeons should refer to both the RCVS and VMD guidance on the cascade.

Although it is not a legal requirement for veterinary surgeons to report adverse events (AEs) to medicines prescribed under the Cascade, the BSAVA would strongly recommend that this is done so that information on adverse events can be collected and made public. Reports of adverse events can be made to the VMD using their online reporting form.


February 2024

Background information

RCVS Guidance on the Cascade:

Veterinary Medicines Directorate: The cascade: Prescribing unauthorized medicines

Veterinary Medicines Directorate reporting form for adverse events (AEs)

Veterinary Medicines Directorate: Import a medicine for veterinary use into the UK

September 2021:

January 2024: VMD introduced enhancements to the digital service to make it easier to use, more secure and reliable, and to meet accessibility legislation. To learn more about the new Import Service, please go to: new import service (

BSAVA Guidance on use of the Cascade:

Prescribing cascade: Chapter from BSAVA Guide to the Use of Veterinary Medicines


Reviewed by members of BSAVA Scientific Committee (Rachel Casey, Gillian Diesel, Ben Garland, Melanie Hezzell, Jeremy Kirk, Caroline Kisielewicz, Michael Rampersad, Sarah Underhill, James Warland) 2023

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