Veterinary Medicines Directorate
About the cascade
Veterinary medicines are authorised for specific conditions for specific target species, based on assessed data. The conditions of use for each authorised veterinary medicine are listed in its Summary of Product Characteristics (SPC). Our Product Information Database contains the SPCs and the authorised territory of all veterinary medicines authorised in the UK. These will be indicated by GB-only, NI-only or UK wide.
Where there is no suitable veterinary medicine authorised in your territory for the specific condition in the animal being treated, to avoid unacceptable suffering, you are permitted to use your clinical judgement to treat animals under your care in accordance with the cascade.
The cascade is a risk-based decision tree. Prescribing decisions in accordance with the cascade should be made on a case-by-case basis. For example, if a suspected adverse event occurred when using a medicine in an animal, this does not mean that the cascade should be routinely used when treating other animals.
The steps, in descending order of suitability, are:
For vets in Great Britain:
| Step | Permitted source |
|---|---|
| Step 1 | Veterinary medicine with a Marketing Authorisation valid in GB or UK wide for indicated species and condition |
| Step 2 | Veterinary medicine with a Marketing Authorisation valid in NI for indicated species and condition, in accordance with a Special Import Certificate granted by the VMD |
| Step 3 | Veterinary medicine with a Marketing Authorisation valid in GB, NI or UK wide for a different species or condition. For products not authorised in GB or UK wide a Special Import Certificate from the VMD is required |
| Step 4 | Human medicine with a Marketing Authorisation valid in GB, NI or UK wide OR an authorised veterinary medicine from outside of the UK. For products not authorised in GB or UK wide a Special Import Certificate from the VMD is required; in the case of a food-producing animal the medicine must be authorised for a food-producing species |
| Step 5 | Extemporaneous preparation prepared by a vet, pharmacist or person holding an appropriate Manufacturers Authorisation, located in the UK |
| Exception | In exceptional circumstances, a human medicine may be imported from outside of the UK. For products not authorised in GB or UK wide a Special Import Certificate from the VMD is required |
For vets in Northern Ireland:
| Step | Permitted source |
|---|---|
| Step 1 | Veterinary medicine with a Marketing Authorisation valid in NI or UK wide for indicated species and condition |
| Step 2 | Veterinary medicine with a Marketing Authorisation valid in NI or UK wide for a different species or condition |
| Step 3 | Human medicine with a Marketing Authorisation valid in NI or UK wide OR a veterinary medicine with a Marketing Authorisation valid in an EU member State. For products not authorised in NI or UK wide a Special Import Certificate from the VMD is required; in the case of a food-producing animal the medicine must be authorised for a food-producing species |
| Step 4 | Extemporaneous preparation prepared by a vet, pharmacist or person holding an appropriate Manufacturers Authorisation, located in UK |
| Exception | In exceptional circumstances, a veterinary medicine with a Marketing Authorisation in GB or outside the EU may be imported, or a human medicine from outside of NI. For products not authorised in NI or UK wide a Special Import Certificate from the VMD is required |
As the prescribing vet you are personally responsible for the choice of product and, as part of the Royal College of Veterinary Surgeons (RCVS) Code of Professional Conduct for Veterinary Surgeons, you must obtain the owners consent for their animal to be treated under the cascade. You must also maintain accurate records.
You, or a person acting under your supervision, may administer a product prescribed under the cascade; however, the prescription and use of the product remains your responsibility.
When using a product under the cascade, you should balance the expected benefits to the animal with the risks of using a medicine under the cascade. Risks could include those to:
- the animal
- the owner
- the person administering the medicine
- consumers of produce from treated animals which may contain residues of the veterinary medicine
- the environment
- wider public health, for example increased selection for antimicrobial resistance
When prescribing medicines under the cascade, you must first carry out a clinical assessment of the animal which must be under your care. You must also ensure that the evidence base for your prescribing decisions is robust and complies with Routine Veterinary Practice (RVP). This is particularly important when prescribing medicines lower down the cascade; if the treatment does not comply with RVP, it may require licensing by the Home Office as a regulated procedure under the Animal (Scientific Procedures) Act. Further guidance on RVP is available from the RCVS.
Misuse of the cascade
You must not promote or facilitate any use of the cascade which is not in accordance with Schedule 4 of the Veterinary Medicines Regulations (VMR). This does not prevent a vet from discussing treatment options with the owner or keeper of the animal under treatment.
Dispensing
Only vets registered with the RCVS may prescribe medicines under the cascade.
A Suitably Qualified Person (SQP) may supply an authorised veterinary medicine that falls within the scope of the registration they hold, against a prescription from a vet for use under the cascade. A pharmacist may dispense authorised veterinary and human medicines, and extemporaneous preparations they have prepared, against a prescription from a vet for use under the cascade.
Food-producing species
For use in GB
The following conditions apply when prescribing a product under the cascade for use in food-producing species:
- all substances contained in the medicine must be substances which:
- have a Maximum Residue Limit (MRL), but not necessarily in the species for which it is intended to be used, or
- do not fall within the scope of assimilated Regulation (EC) No 470/2009.
- when checking this, you should also consider the other provisions listed with the MRL, for example, some substances are not allowed for use in animals producing eggs or milk for human consumption
- substances with an MRL are listed in theGB MRL Registeras established under Article 14A of assimilated Regulation (EC) No 470/2009
- the vet responsible for prescribing the medicine must specify an appropriate withdrawal period
- the vet responsible for prescribing the medicin