Serum Level Digoxin Toxicity Among Congestive Heart Failure Patients At Tikur Anbessa Generalized Specialized Hospital

Background: digoxin is an important drug in the treatment of congestive heart failure due to left ventricular dysfunction and it is one of the drug that increase ventricular contraction. Previous studies that shows high prevalence of digoxin toxicity was conducted before the widespread measurement of serum digoxin concentrations to monitor drug treatment. Due to narrow therapeutic window of digoxin and increasing mortality and morbidity as the result of intoxication make serum digoxin measurements an essential point of concern. Objectives: To assess the prevalence of serum digoxin toxicity and to identify associated risk factors among congestive heart failure patients who take digoxin treatment at Tikur Anbesa hospital, Addis Ababa, Ethiopia Patients and Methods: demographic data of 80 patients with heart failure were collected form medical record and by interviewing the study participants. Serum digoxin levels were evaluated by electrochemiluminesence. Patients' serum was also assayed for serum electrolyte, urea, creatinin, magnesium and calcium. Data was analyzed by SPSS 15 and result was compared with serum digoxin level. Therapeutic range of digoxin in patients to be used as a reference was 0.5 to 2.0ng/ml. Results: eleven (13.8%) patients showed higher level of serum digoxin, 6 (54.5%) had hypercalcemia and 5 (45.5%) had calcium level below 1.32mmol/l. Potassium level of this patients was with hypokalemia (<3.5mmol/l) for 8 (72.7%) and hyperkalemia (>3.5mmol/l) for 3 (27.3%). Two (18.2%) of patient with Hyponatremia and 9 (81.8%) with normal sodium level had serum digoxin toxicity. Similarly 8 (72.7%) had hypomagnesaemia(<0.66mmol/l) Conclusion: our study indicated that serum digoxin toxicity were 13.8% and overall electrolyte abnormality were 40% in congestive heart failure patients. Considering the narrow therapeutic window of digoxin, periodical monitoring of serum digoxin levels must be conducted in all patients receiving digoxin. Nevertheless, electrolyte determination plays an important role in predicting of digoxin toxicity.