Ketamine detection in urine samples from patients poisoned by recreational drugs: epidemiologic, clinical, and toxicologic profiles

Objective. To describe the epidemiologic, clinical, and toxicologic profiles of patients who used recreational ketamine and experienced acute poisoning. Methods. Retrospective observational study of patients attended by several emergency medical services in the Balearic Islands for analytically confirmed acute poisoning after using ketamine between January 2016 and December 2020. Urine samples were analyzed by immunoassay and combined gas chromatography and mass spectrometry. Results. One hundred twenty-two patients were studied. The mean (SD) age was 26.7 (6.5) years. The majority were men (77.9%) and not residents of the Balearic Islands (74.6%). Poisoning cases occurred mainly in the summer and in the island of Ibiza (84.4%). Ketamine use was declared by the patient or clinically suspected in 40.2%. The most common clinical signs were tachycardia (43.4%), hypertension (28.7%), mydriasis (27.0%), altered consciousness (25.4%), agitation/aggressiveness (25.4%), and hypothermia (21.3%). Seven patients (5.73%) required admission to the intensive care unit. The drugs most often detected along with ketamine were cocaine, in 93.4%, and 3,4-methylenedioxymethamphetamine (MDMA), in 78.7%. Multiple-drug use combining ketamine, cocaine, and MDMA, or on occasion additional substances, was detected in 98.4%. Conclusions. Detection of ketamine in urine samples from patients poisoned by recreational drugs is associated with a characteristic profile: young men who are not residents of the Balearic Islands, who attend electronic music concerts, and who have taken multiple drugs. A substantial percentage of such patients are unaware of drug intake.