Suicidal ingestion of organophosphorus (OP) or carbamate (CM) compounds challenges health care systems worldwide, particularly in Southeast Asia. The diagnosis and treatment of OP or CM poisoning is traditionally based on the clinical appearance of the typical cholinergic toxidrome, e.g. miosis, salivation and bradycardia. Yet, clinical signs might be inconclusive or even misleading. A current case report highlights the importance of enzymatic assays to provide rapid information and support clinicians in diagnosis and rational clinical decision making. Furthermore, the differentiation between OP and CM poisoning seems important, as an oxime therapy will most probably not provide benefit in CM poisoning, but-as every pharmaceutical product-it might result in adverse effects. The early identification of the causing agent and the amount taken up in the body are helpful in planning of the therapeutic regimen including experimental strategies, e.g. the use of human blood products to facilitate scavenging of the toxic agent. Furthermore, the analysis of biotransformation products and antidote levels provides additional insights into the pathophysiology of OP or CM poisoning. In conclusion, cholinesterase activities and modern analytical methods help to provide a more effective treatment and a thorough understanding of individual cases of OP or CM poisoning.

Oximes such as pralidoxime (2‐PAM), obidoxime (Obi), and HI‐6 are the only currently available therapeutic agents to reactivate inhibited acetylcholinesterase (AChE) in case of intoxications with organophosphorus (OP) compounds. However, each oxime has characteristic agent‐dependent reactivating efficacy, and therefore the combined administration of complementary oximes might be a promising approach to improve therapy. Accordingly, a new high‐performance liquid chromatography method with diode‐array detection (HPLC‐DAD) was developed and validated allowing for simultaneous or single quantification of 2‐PAM, Obi, and HI‐6 in human plasma. Plasma was precipitated using 5% w/v aqueous zinc sulfate solution and subsequently acetonitrile yielding high recoveries of 94.2%–101.0%. An Atlantis T3 column (150 × 2.1mm I.D., 3 μm) was used for chromatographic separation with a total run time of 15 min. Quantification was possible without interferences within a linear range from 0.12 to 120 μg/mL for all oximes. Excellent intra‐day (accuracy 91.7%–98.6%, precision 0.5%–4.4%) and inter‐day characteristics (accuracy 89.4%–97.4%, precision 0.4%–2.2%) as well as good ruggedness were found. Oximes in processed samples were stable for at least 12 h in the autosampler at 15°C as well as in human plasma for at least four freeze–thaw cycles. Finally, the method was applied to plasma samples of a clinical case of pesticide poisoning.

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