Clinical Toxicological Follow-Up Analysis of a Suicide Attempt Using Chloroquine.

Chloroquine, a drug approved for the treatment of malaria, is frequently used to commit suicide. We report about a suicide attempt by ingesting a high dose of chloroquine in combination with other drugs. Findings of the emergency toxicology screening of blood and urine and those of the follow-up analyzes in blood are discussed. Systematic toxicological analysis approaches revealed the presence of chloroquine, butylscopolamine, cafedrine, diazepam, lorazepam, metoclopramide, nordazepam, norephedrine, and THC-COOH in blood and/or urine of the subject. Suicide due to a combination of chloroquine and benzodiazepines is known as the so-called "Kusch method" in German-speaking countries. The initial chloroquine plasma concentration was determined to be 9.6 mg/L after precipitation and analysis by liquid chromatography-high-resolution tandem mass spectrometry. The analytical procedure was developed ad hoc and validated in accordance with international recommendations. Clinical toxicological follow-up analyses in blood were performed over a period of three weeks. The chloroquine concentration remained for two weeks above the therapeutic range (up to 0.5 mg/L) and dropped to 0.3 mg/L after three weeks. Furthermore, monodesethylchloroquine (MDCQ) and bisdesethylchloroquine (BDCQ) were determined to be the most abundant metabolites in plasma. Within three weeks, the area ratios of MDCQ and chloroquine increased fourfold (from 0.090 to 0.350) and of BDCQ and chloroquine a hundredfold (from 0.002 to 0.218). This information may help to estimate the chloroquine excretion progress in the future.