the outbreak of lead poisoning in opium users: presentation and chelation therapy

Recently, there have been a few reports of an outbreak of lead poisoning due to opium contaminated with lead in iran. this study aimed to evaluate the clinical features of lead toxicity in opium abusers, and response to oral chelation therapy based on the severity of poisoning. one hundred thirty-three chronic opium users with a diagnosis of lead poisoning were included. based on blood lead level (bll), the cases were divided into 2 mild (bll;40-69 μg/dl) and moderate (bll;70-100) groups. both groups received d-penicillamine (d-p) as a chelator. changes in bll compared between two groups. all cases were oral opium users. abdominal pain (75%), anorexia (55.6%), and constipation (53.2%) were the most common symptoms of lead poisoning. 67.8% of cases experienced only one round of chelation therapy and rebound phenomenon happened in 9% of these. ninety percent of the patients had wellbeing sensation, and symptoms improved at the end of the first round of treatment. the mean bll before and after chelation therapy were 66.87 and 45.7 μg/dl, respectively. oral chelator reduced bll in both mild and moderate poisoning groups (35.61% vs. 35.90%, p: 0.057), respectively. the comparison of bll before and after chelation therapy showed that the treatment was effective equally in both mild and moderate toxicity. however, in a few cases, the rebound phenomenon may occur.