Adverse Drug Reactions

All veterinary medicinal products have the potential to cause adverse effects and no effective medicinal product is risk free. When a veterinary medicinal product is first authorised, some of the adverse effects are known. However, the knowledge of the product at the time of authorisation is relatively limited as it is based on the use of the medicine under controlled conditions e.g. in pre-clinical and clinical trials. Therefore some adverse effects may only become known after wider use of the veterinary medicinal product in the target species, for example, adverse events which may occur more rarely or in specific breeds or groups of animals.

An adverse event is defined as any observation in animals, whether or not considered to be product-related, that is unfavourable and unintended and that occurs after any use of a veterinary medicinal product (off-label and on-label uses). This includes adverse reactions and events related to suspected lack of expected efficacy when the product is used according to the approved labelling.

Adverse reactions to veterinary medicinal products can cause many different clinical signs and type I, type II, type III, type IV or combined hypersensitivity. It does not require previous exposure to the particular drug because it can develop within the course of repeated drug administration. It is not necessarily related to the dose of drug. Different species may be more sensitive to different drugs.

Clinical management of hypersensitivity reactions:

• Withdrawl from drug
• Corticosteroids if required

• If anaphylactic reaction has occurred then in the acute stages adrenaline and fluid therapy are required.

Reporting adverse events Adverse reactions to drugs including lack of expected efficacy occurring in the United Kingdom should be reported to the Veterinary Medicines Directorate (VMD) on their form MLA252A. Adverse events occurring in other European Union (EU) Member States, Norway, Iceland and Liechtenstein, should be reported to the relevant competent authority where the event occurred using the EU reporting forms for veterinarians which are available in each EU language on the European Medicines Agency website.

The science and activities relating to the detection, assessment, understanding and prevention of adverse effects or any other veterinary medicine-related problem is called veterinary pharmacovigilance. Further information on veterinary pharmacovigilance in the European Union, is available via the European Medicines Agency and EudraVigilance Veterinary websites.

Adverse Drug Reactions Learning Resources
Full Text Articles Full text articles available from CAB Abstract (CABI log in required)	Cutaneous adverse drug reactions. DeBoer, D. J.; Eastern States Veterinary Association, Gainesville, USA, Small animal and exotics. Proceedings of the North American Veterinary Conference, Volume 19, Orlando, Florida, USA, 8-12 January, 2005, 2005, pp 237-238