A novel, safe and effective chelating regimen for treatment of Lead toxicity

Abstract

Introduction

                Lead toxicity is a recognized occupational hazard with long term morbidity and mortality. Still, treatment guidelines regarding choice and doses of chelating agents are not     standardised¹. We present a novel and safe low dose        intermittent regimen of calcium disodium EDTA² (CaNa₂EDTA) used for treating patients with lead toxicity.

Discussion

                A 40 years male, battery factory worker presented with  abdominal cramps, diarrhoea, weight loss, irritability, fine tremors and microcytic hypochromic anaemia  nresponsive to iron supplements for two years. Tests showed haemoglobin 7.8 gm/dl, MCV 75.0 fl with Erythrocyte morphology showing classical basophilic stippling. His serum blood levels were 182.3 ug/dl (Normal: <5ug/dl). Another 23 years old male, painter, with subacute progressive quadriparesis and iron unresponsive microcytic hypochromic anaemia, had blood lead levels 52.3 ug/dl and was diagnosed to have lead   neuropathy. Both the patients received  helation with a novel regimen consisting of low dose (1 gm) CaNa₂EDTA given once a week for eight weeks followed by maintenance with                 d-penicillamine. to non-toxic range in 20 weeks.The first patient showed clinical improvement with  initial two doses of CaNa₂EDTA and blood lead levels reduced to non-toxic range within 24 weeks. The second   patient showed gradual neurological improvement in motor power over 30 weeks with pursuance of functional   activities of daily living and blood lead levels reducedto non-toxic range in 20 weeks.CaNa₂EDTA is usually recommended in a dosage of 50–80 mg/kg/day for 2–5 days, requiring maintenance of hydration, electrolyte monitoring to avoid nephrotoxicity.However, we used a low dose (20 mg/kg) intermittent dosing regimen of CaNa₂EDTA which in addition to avoiding          nephrotoxicity, also prevented rebound elevation of blood lead due to resorption from the bones.