PHARMACOLOGY - The Cascade

Question 1

What does veterinary drug authorisation entail?

Answer 1

Drug authorisation requires assessment of drug quality, safety and efficacy as well as considers potential risks to animals, to the environment, to operaters and consumers. This information is them gathered into a Summary of Product characteristics (SPC)

Question 2

What are the three main problems associated with unauthorised drugs?

Answer 2

May not be of consistent quality
May not be safe and effective in that species
May pose a risk to consumers

Question 3

What are the four excemptions that allow you to use unauthorised drugs?

Answer 3

Drugs administered for research
Exceptional circumstances e.g a disease outbreak
Immunological drugs for imported or exported animals
Use of the Cascade

Question 4

What is the Cascade?

Answer 4

The cascade allows veterinarians to legally prescribe drugs that are not authorised for the relevant clinical case or for the relevant species being treated, when there is no authorised veterinary drug available

Question 5

What should you do before prescribing an unauthorised drug?

Answer 5

When prescribing an unauthorised drug, you should seek written informed consent from the client, making them aware of the intended use of the drug and any potential side effects

Question 6

Who can prescribe a drug using the Cascade?

Answer 6

Only the Veterinary surgeon

Question 7

Who can dispense a drug under the Cascade?

Answer 7

A pharmacist or suitably qualified person (SQP) may dispense a drug under the cascade

Question 8

What are the four extra regulations you must follow when prescribing unauthorised drugs to food producing animals?

Answer 8

Active substance in the drug must have a maximum residue limit (MRL)
Any imported drugs must be authorised in a food producing species in the country of origin
Veterinarians must specify the withdrawal period for that drug
Veterinarians must keep additional records

Question 9

What is the maximum residue limit (MRL)?

Answer 9

The maximum residue limit (MRL) is the maximum concentration of drug or drug metabolite residue that is legally permitted and recognised as acceptable in food following the use of a veterinary medicine

Question 10

What can you use to determine if a drug has a maximum residue limit (MRL) and then thus can be used in a food producing animal?

Answer 10

If the drug is in the allowed substance list on the Great Britain maximum residue limit (MRL) register, or Table 1: Allowed substances for Northern Ireland

Question 11

What is the withdrawal period?

Answer 11

The withdrawal period is a period of time, following the treatment of an animal with a veterinary medicine, in which meat, milk, eggs or honey from the treated animal must not enter the food chain due to the possible presence of residues

Question 12

Who is responsible for setting a withdrawal period?

Answer 12

Veterinary surgeon

Question 13

How do you set a withdrawal period for a veterinary authorised drug?

Answer 13

If you have used the drug in accordance with the summary of product characteristics (SPC), you can use the authorised withdrawal period in the SPC for that drug. However, if you have not used the drug in accordance with the SPC, you should set at least the minimum statutory withdrawal period

Question 14

What is the minimum statutory withdrawal period for eggs?

Answer 14

14 days

Question 15

What is the minimum statutory withdrawal period for milk?

Answer 15

7 days

Question 16

What is the minimum statutory withdrawal period for meat from poultry and mammals?

Answer 16

28 days

Question 17

How long should you keep the additional records required to prescribe an unauthorised drug for a food producing animals?

Answer 17

Minimum of 5 years

Question 18

What is the first step of the Cascade?

Answer 18

Choose a veterinary medicine authorised in Great Britain or UK wide for use in the indicated species and condition

Question 19

What is the second step of the Cascade?

Answer 19

If step one is not possible, choose a veterinary medicine authorised in Northern Ireland for the indicated species and condition

Question 20

What is required to use veterinary medicines authorised in Northern Ireland?

Answer 20

Special Import Certificate (SIC) from the VMD

Question 21

What is the third step of the Cascade?

Answer 21

If step two is not possible, use a veterinary medicine authorised in Great Britain, Northern Ireland or UK wide for use in a different species for the same condition or for another condition in the same species

Need an SIC for Northern Ireland

Question 22

What is step four of the Cascade?

Answer 22

If step three is not possibe, use a human medicinal product authorised in Great Britain, Northern Ireland or the UK, or, use an authorised veterinary medicine from outside the UK (will require an SIC)

Question 23

What is step five of the Cascade?

Answer 23

If step four is not possible, use an extemporaneous preparation prepared by a vet, pharmacist or person holding a Manufacturer’s authorisation in the UK

Question 24

What should you check to ensure a horse has been signed out of the food chain?

Answer 24

Check section IX: Admnistration of Veterinary Medicinal products, Part II of the horse passport to ensure the horse is not intended for human consumption

Question 25

Where in the passport should you record administration of veterinary medicines in a horse intended for human consumption?

Answer 25

Section IX: Admnistration of Veterinary Medicinal products, Part III

Question 26

What steps should you take before prescribing for a horse?

Answer 26

1. Check the microchip and cross check with the passport to make sure the passport relates to the correct horse
2. Check section IX of the passport and ask the owner if they would like to sign their horse out of the food chain if they haven’t already done so
3. Make a note of this in the clinical records

Question 27

Which legislation should you follow when prescribing for a horse not for human consumption?

Answer 27

Follow the same legislation as you would for prescribing to a companion, non-food producing animal and follow the normal Cascade

Question 28

Which legislation should you follow when prescribing for a horse intended for human consumption?

Answer 28

Follow the legislation for food producing animals. However, in horses you can use the Essential substances list in addition to the MRL register to determine which drugs are allowed to be prescribed

Question 29

What is the Essential substances list?

Answer 29

The Essential substances list is a list of additional drugs that can be used in horses intended for consumption

Question 30

What is the withdrawal period for any drug on the Essential substances list?

Answer 30

Minimum of 6 months

Question 31

How should you approach treating a horse without a passport?

Answer 31

• First determine if it is necessary to treat the horse immediately
• If the horse requires immediate treatment, treat them as ‘intended for human consumption’
• In an emergency, if the health/welfare of the horse is at risk, treatment with a drug not allowed for food producing animals is permitted (however you must issue the client detailed documents of the medications administered and instructions to exclude the horse from the food chain)

Question 32

Give an example of an NSAID that cannot be used in horses intended for human consumption?

Answer 32

Phenylbutazone