Adverse Drug Reactions During Intensive Phase of Treatment Among Multi- Drug Resistant Tuberculosis Cases Registered at a DR-TB Centre of Southern India

Background: Multiple drugs and long duration of treatment increases the incidence of Adverse Drug Reactions (ADRs) during MDR-TB treatment.ADRs may affect treatment adherence, lead to drop-outs, change in treatment regimen, increased cost.This study was conducted to study the incidence, determinants, causality, severity and chances of preventability of ADRs among MDR-TB cases registered at a DR-TB centre, Bangalore.Methodology: This longitudinal study employed non-probability sampling to recruit adult MDR-TB cases registered and initiated on treatment and followed them till the end of intensive phase for occurrence of any ADRs.Causality, Severity and chances of preventability of ADRs were assessed by WHO UMC causality, Hartwig's severity and Modified Schumock & Thorton scale respectively.Results: Among the 103 MDR-TB cases, majority were males 67(65%);38 (36.9%) in age group 31-45 years and 54 (52.4%) belonged to urban area.A total of 36 ADR episodes occurred among 20 (19.4%) subjects, resulting in an ADR incidence of 5.8 (95% CI: 1.3 -10.3) per 100 person-months, with an average of 1.8 episodes per person experiencing ADRs.WHO-UMC scale revealed, 28 out of 36 ADRs were likely caused by drug reactions, 8 were unassessable.All 36 were mild as per Hartwigs Severity.As per modified Schumock and Thorton scale, 28 (77.8%) were 'Probably preventable' and 12 were 'not preventable'.Conclusion: All ADRs were mild in severity and 77.8% could be probably preventable.Hence, strengthening of reporting of ADR would reduce the incidence and probably result in better management of cases.