First do no harm - understanding why adverse drug reactions can occur and if and when they can be prevented (SVS25)

An adverse drug reaction (ADR) is a reaction which is harmful, unintended and which occurs at doses normally used for prophylaxis, diagnosis or treatment of disease or the modification of physiological function. All drugs have the potential to result in an ADR. ADRs present a continuum of clinical significance, but of greatest concern are serious ADRs described as adverse drug reactions that are fatal, life threatening, disabling, incapacitating or which result in permanent or prolonged adverse clinical signs. There are different types of ADRs – some of which can be avoided if sufficient is known about the drug and patient – hence the importance of understanding basic pharmacological principles. Others, such as drug hypersensitivity reactions, may not be avoidable the first time they occur. This lecture will review how ADRs are classified, the factors that increase the risk of an ADR occurring in an individual patient and issues that impact on whether an ADR is reported to the manufacturer or government authority.

Practitioners can make a massive contribution to the ongoing appropriate use of veterinary medicines by recognising and reporting suspected adverse reactions. Important examples include the practitioner reported association of ivermectin use in dogs and adverse neurological effects and the use of high doses of enrofloxacin in cats leading to apparent blindness. Once the profession was alerted and additional cases reported, investigation was possible and resulted in the identification of genetic predispositions in certain dogs and all cats. Reporting is important and a responsibility we all have.

• Recognise the different types of adverse drug reactions (ADR) that can occur
• Recognise the patient factors that can increase the risk of an ADR
• Appreciate the important role that practitioners have in supporting the ongoing appropriate use of veterinary medicines by recognising and reporting suspected adverse reactions