A Study of Drug Radiopacity by Plain Radiography

Plain abdominal X‐ray (AXR) may be helpful in the management of acute poisoning in the emergency department if the drugs involved are radiopaque. There are varying radiopacity among different medications and even for the same medication from different manufacturers. Therefore, we performed this study to detect local drug radiopacity in Hong Kong. A total of 430 drugs under the formulary of the United Christian Hospital were tested by standard AXR (75 kV, 23 mA) in a specially designed box which corresponded to the soft tissue density of the abdomen. Two different radiologists classified the drug radiopacity into three grades. Eight drugs (1.9%) were graded as definitely radiopaque (ranitidine bismuth citrate, tripotassium dicitratobismuthate, Drixoral SR, amiodarone, ferrous sulphate, sodium chloride, calcium carbonate, and Cafertamin). Another 129 drugs (30.0%) were slightly radiopaque, including slow release drugs, neuroleptics, antacids, ionic salts, beta‐blockers, tricyclic antidepressants, antibiotics and others. The remaining 293 drugs were undetectable. As a significant number of drugs (31.9%) were detectable by plain AXR in vitro and some of them were potentially lethal, we should consider AXR as an adjunct in managing a suspected poisoned patient. Further study may be needed to evaluate these drugs' radiopacity in vivo with respect to the dosage and time of ingestion to assess its clinical application.