Introduction: According to the World Health Organization (WHO) definition, an Adverse Drug Reaction
(ADR) is a response to a drug that is noxious and unintended and occurs at doses normally used in humans for the
prophylaxis, diagnosis, and treatment of disease. The risk factors of ADR are multi-factorial and include poly-pharmacy,
age, gender, race, genetics and inter-current disease.
Patients and Methods: This was a hospital based, prospective, observational cohort study undertaken in a tertiary care
hospital in south India to assess the different patterns of adverse drug reaction in medical wards over 6 months. The
severity of ADR was assessed using Hartwig Siegel scale and causality by Naranjo and WHO UMC Scale. Preventability
was assessed using Schumock and Thornton scale and other parameters such as incidence, onset, duration, management
and outcome were also assessed. Risk factors were assessed by bi-variate logistic regression analysis and length of
hospital stay by T test.
Results: The incidence of ADR was 10.42% in medicine wards. The causality of ADR done by Naranjo scale showed that
most of the ADRs were probable (7.38%). Anti-tubercular agents were the leading cause of ADR. Duration of
hospitalization was significantly longer (7.18 ± 2.64 vs. 5.06 ± 2.13 days) in patients with ADR (Odds ratio 1.38, 95%
Confidence interval 1.26 to 1.51). 7.28% of ADRs were moderately severe. Seriousness criteria assessment showed that
0.33% were serious reactions. Most of the ADRs were definitely preventable. Most of the ADRs were managed by
discontinuing the suspected drug. The present study showed female gender predominance over males for ADRs and no
relationship with age.
Conclusion: Adverse drug reactions impose significant burden on hospitals through prolonging patient stay and by
increasing admission rates. The occurrence of ADR in this study was higher when compared to that reported in previous
studies. This study highlights the importance of ADR reporting among ADR reporting among health care professionals in