DOI: 10.36347/sjams.2013.v01i05.008

Pages: 386-392

Adverse drug events ranges from mild to life threatening reactions which results in inconvenience or serious morbidity and mortality. Clinicians often do not recognize drug related harm. Terms used to describe these events with medication use cause much confusion. Moreover manifestations of adverse drug reactions can be non-specific making difficult to differentiate from current illness. To determine the likelihood of relationship between the drug and the event, assessment of causality is done which is rather the important task in conducting the National Pharmacovigilance Programme in each country. Despite the great number of methods proposed, assessing the causal role of a drug in the occurrence of an adverse medical event remains one of the most controversial issues. Qualifying terms for criteria, such as “compatible”, “suggestive” or “inconclusive”, have never been strictly defined, leading to low reproducibility. So, in order to have a harmony in defining the criteria of causality assessment, researchers started developing different methods for causality assessment. All these methods were classified in three broad categories: expert judgement/global introspection, algorithms and probabilistic methods (Bayesian approaches). As a result of problems of reproducibility and validity, no single method is universally accepted. Different causality categories are adopted in each method, and the categories are assessed using different criteria. Because assessment methods are also not entirely devoid of individual judgements, inter-rater reliability can be low. In conclusion, there is still no method universally accepted for causality assessment of ADRs.