Randomized placebo-controlled trial of 2,3-dimercaptosuccinic acid in therapy of chronic arsenicosis due to drinking arsenic-contaminated subsoil water

Introduction: Chronic arsenic toxicity producing various clinical manifesta tions is currently epidemic in West Bengal, India, Bangladesh, and other re gions of the world. Animal studies have indicated that 2,3-dimercaptosuccin ic acid can be used as an oral chelating agent. A prospective, double-blind , randomized controlled trial was carried out to evaluate the efficacy and safety of 2,3-dimercaptosuccinic acid for chronic arsenicosis due to drinki ng arsenic-contaminated (greater than or equal to 50 mu g/L) subsoil water in West Bengal. Method: Twenty-one consecutive patients with chronic arseni cosis were individually randomized (random number; assignment made by indiv idual not evaluating patients) into 2 groups: II patients (10 male, age 25. 5+/-8 years) received 2,3-dimercaptosuccinic acid 1400 mg/d (1000 mg/m(2)) in the first week and 1050 mg/d (750 mg/m(2)) during the next 2 weeks with a repeat course 3 weeks later. The other 10 patients (all male, age 32.2+/- 9.7 years) were given placebo capsules for the same schedule. The clinical features were evaluated by an objective scoring system before and after tre atment. Routine investigations including liver function tests, arsenic conc entrations in urine, hair, and nails, and skin biopsy evaluations were also completed. Results: Though there was improvement in the clinical score of 2,3-dimercaptosuccinic acid-treated patients, similar improvement was obser ved in the placebo-treated group. There were no statistical differences in the clinical scores between the 2 groups at the beginning and at the end of treatment. Similarly, no differences were found for the other investigated parameters. Conclusion: Under the conditions of this study, 2,3-dimercapto succinic acid was not effective in producing any clinical or biochemical be nefit or any histopathological improvement of skin lesions in patients with chronic arsenicosis.