Abstract

STUDY OF RELATIONSHIP BETWEEN SERUM CONCENTRATIONS AND ADVERSE EFFECTS OF AMIODARONE IN PATIENTS AT MEDICINE DEPARTMENT, ST. MARTHA’S HOSPITAL, BANGALORE

*Prathyusha Dwivedula¹, Shobha Rani R Hiremath¹, Jayanthilal², Ramjan Shaik¹.

ABSTRACT

Amiodarone is a potent anti-arrhythmic drug. Its clinical use is limited by its unusual pharmacokinetics and toxicity. Adverse reactions are frequent in long term treatment and certain adverse effects are severe and fatal. Studies suggest the risk of developing adverse reactions relates to serum amiodarone concentrations. The present study aims to correlate the serum concentrations of amiodarone with observed adverse effects. Initial baseline serum concentration of the drug was determined using HPLC analytical technique for each patient and was followed-up for any adverse drug reactions in which case, the drug concentration was re-analyzed. During the study period of 9 months, 25 patients were enrolled in the study. 18 out of 25 patients, had history of arrhythmia ranging from 3 months to 2 years. The serum concentrations of amiodarone ranged from 0.3 to 1.25 μg/ml in the patients. Out of 25 patients, 14 experienced adverse effects, of whom 9 patients experienced major reactions like hypothyroidism [4(29%)] followed by hepatic enzyme elevation [4(29%)] and bradyarrhythmia [1(7%)]. Minor reactions were observed in 5 patients viz. skin rash [3(21%)] followed by constipation and hypotension in 1 patient each. As per WHO Probability Scale and Naranjo Algorithm, 86% of adverse reactions were found to be possibly due to the exposure of amiodarone. Overall, the plasma concentrations of amiodarone were not helpful for the prescription of therapy. It was found that there is no association of serum amiodarone levels with adverse reactions, as the concentration of amiodarone in patients with adverse effects was within the therapeutic range.

Keywords: Adverse Drug Reactions, Amiodarone, Arrhythmia, Bradyarrhythmia Hypothyroidism.