Pharmacovigilance is the monitoring of unwanted or adverse reactions to medicines and vaccines. For veterinary surgeons, veterinary nurses and animal owners, this monitoring is done through the Suspected Adverse Reactions Surveillance Scheme (SARSS). The reporting of reactions is not currently mandatory in the UK for these groups, but there are legal obligations on medicines manufacturers and distributors (see Veterinary Medicines Regulations (VMR) Part 8).

The reporting of suspected adverse reactions is a key part of the process of ensuring the safety of medicines, and also plays a part in keeping existing medicines on the market and available.

Who can report an adverse reaction?
Suspected adverse reaction reports can be filed by anyone. In practice, most are submitted by veterinary surgeons. Reports should be sent to the Veterinary Medicines Directorate (VMD) and also to the manufacturer or distributor of the medicine where this is known.
Where the manufacturer is a member of the National Office of Animal Health (NOAH) and authorizes further investigation of an incident, they will meet the costs involved.

What is an adverse reaction?
Adverse reactions are harmful and unintended reactions to a medicine when administered to an animal at its recommended dosage and route of administration. Adverse reactions in animals that should be reported include:

• Lack of expected efficacy, including resistance to antibiotic or antiparasitic agents
• Reactions not mentioned in the datasheet
• Reactions mentioned in the datasheet, but occurring more frequently or more severely
• Reactions arising during clinical use of a new medicine under development (Animal Test Certificate)
• Any reaction to a medicine which has been authorized for less than a year
• Reactions arising during ‘off-label’ use (i.e. under the prescribing cascade)
• Environmental problems.

The VMD and manufacturers will categorize the reaction as minor or serious. Examples of reactions which would be regarded as serious are listed in the VMD Veterinary Medicine Guidance Note, number 13.

Reactions in animals to human medicines
Veterinary surgeons may use medicines authorized for use in humans under the prescribing cascade. The number of reactions reported following such use is low. The VMD encourages veterinary surgeons to be on the look out for such reactions and to report them in the usual way.

Adverse reactions in humans
There may also be adverse reactions in humans following exposure to a veterinary medicine. The legal definition of a Human Adverse Reaction (HAR) is ‘a reaction that is noxious and unintended and that occurs in a human being following exposure to a veterinary medicine’.

There is a questionnaire that should be completed when reporting such reactions or in the case of accidental injection and sent to the VMD at the address below.

How to report
For most reactions, a SARSS form (Form MLA 252A) should be completed. Copies can be found in the BSAVA Small Animal Formulary or in the NOAH Datasheet Compendium. Copies can also be downloaded. If the reaction is a result of the animal being exposed after environmental contamination with a veterinary medicine, then a separate form is used (MLA 1 (A5)).

Completed forms should be sent to:
The Veterinary Medicines Directorate
FREEPOST KT 4503
New Haw
Addlestone
Surrey KT15 3BR

Where the manufacturer or distributor of the medicine which caused the reaction is known, they should also be contacted. Contact details are listed in the NOAH Datasheet Compendium or on the medicine package. It is a legal requirement for each company to have a designated member of staff responsible for pharmacovigilance.

What happens to the report?
Reports are collated by the manufacturer and used as part of the ongoing safety monitoring of all medicines. Information on serious adverse reactions and reactions in humans to veterinary medicines must be reported to the VMD within 15 days. Reports are classified under the ABON system:

• A The medicine probably caused the reaction observed
• B  The medicine possibly caused the reaction observed
• O There is insufficient information to judge if the medicine caused the reaction
•  observed
• N The medicine probably did not cause the reaction observed.

Reports from all European Union countries are collated by the European Commission. Quarterly summaries of the reports received are published in the Veterinary Record and in the VMD journal MAVIS.

Useful websites
BVA Good Practice Guide on Veterinary Medicines
European Veterinary Pharmacovigilance
NOAH – Pharmacovigilance