Intoxications involving MDPV in Sweden during 2010-2014: Results from the STRIDA project (2015)

Context: In the recent years, there have been an increasing number of new psychoactive substances (NPS) available through marketing and sale on the Internet. The stimulant 3,4-methylenedioxypyrovalerone (MDPV) is a potent dopamine reuptake inhibitor, which can cause serious intoxications requiring intensive care and even fatality. This report from the STRIDA project presents the prevalence, laboratory results, and clinical features in a series of intoxications involving MDPV over a 5-year period.
Study design: Observational case series of consecutive patients with admitted or suspected intake of NPS presented at hospitals in Sweden from 2010 to 2014.
Patients and methods: Blood and/or urine samples were collected from intoxicated patients with admitted or suspected intake of NPS presenting at hospitals over the country. Analysis of NPS was performed by a liquid chromatography-tandem mass spectrometry multicomponent method. Clinical data were collected when caregivers consulted the Swedish Poisons Information Centre and also retrieved from medical records. The severity of poisoning was graded retrospectively using the poisoning severity score.
Results: During the 5-year study period, the number of MDPV-related inquiries to the Poisons Information Centre was 662 out of a total ~4500 suspected NPS-related inquiries (~15%), and 201 analytically confirmed MDPV intoxications were enrolled in the study. The study period covered the period when the use of MDPV in Sweden was at its peak and also the decline to an almost zero level. The age range of patients was 18-68 (mean 36, median 35) years, and 71% were males. The MDPV concentrations in serum ranged between 1.0 ng/mL and 1509 ng/mL (mean 63.6, median 20) and between 1.0 ng/mL and 81 000 ng/mL (mean 3880, median 1160) in urine. The urinary values were also creatinine corrected for variation in urine dilution, and the MDPV/creatinine ratio ranged between 0.10 ng/mmol and 2480 ng/mmol (mean 247, median 92.6). There was a statistically significant association between the serum MDPV concentration and the urinary MDPV/creatinine ratio, for 118 cases where both data were available (r = 0.764; p < 0.0001, Spearman's rank correlation). In 30 (15%) cases, MDPV was the single psychoactive substance identified in the serum or urine specimens. In the other 171 cases, other psychoactive substances were detected together with MDPV. The additional substances (n = 61) comprised of both conventional drugs of abuse, other NPS (n = 39), pharmaceuticals, and ethanol. The cathinone-derivative alpha-pyrrolidinovalerophenone (alpha-PVP) was the most frequent other NPS, and was detected in 58 (29%) cases, followed by methylone in 14 (7%) cases. The main clinical manifestations reported in patients testing positive for MDPV included agitation, tachycardia (>=100/min), and hypertension (systolic blood pressure >=140 mmHg), which were observed in 130 (67%), 106 (56%), and 65 (34%) cases, respectively. Other symptoms included hallucinations (n = 31, 16%), delirium (n = 29, 15%), hyperthermia (>39°C/102.4°F; n = 18, 10%), and rhabdomyolysis (n = 16, 8%). In MDPV intoxications with serum levels >100 ng/mL, the cases were graded as more severe and hyperthermia was less common.
Conclusions: In a large number of analytically confirmed MDPV intoxications from mostly polydrug users, the urine and serum MDPV concentrations showed a high variability. The clinical features were consistent with a severe sympathomimetic toxidrome. The results also demonstrated that MDPV prevailed as a drug of abuse for a long time, after its classification as a narcotic substance and despite a high incidence of severe poisonings.