Assessment of Acute Methylphenidate Toxicity

Introduction: Despite years of use, there is little data about the toxic dose/effect relationship of methylphenidate. We attemptedto identify dose thresholds between different severities of poisoning according to the Poison Severity Score (PSS).Methods: Retrospective cross-sectional study including all mono-methylphenidate exposures registered by a regional PoisonCenter between January 2002 and July 2018. We identified 433 cases. Receiver Operating Characteristics (ROC) analyses indifferent age groups were performed to identify the cut-off with the best sensitivity and specificity in relation to the severity ofintoxication by PSS (none/asymptomatic, mild, moderate, severe).Results: Overall, 392 different individual symptoms were reported. These were the significant cut-off values to differentiatebetween severity of intoxication: for adults (18 to 65 years) 175 mg for asymptomatic vs. mild intoxications (AUC 0.63, p=0.005).In adolescents (14 to 17 years) 95 mg for asymptomatic vs. mild intoxications (AUC 0.64, p=0.007). In pupils (7 to 13 years)53 mg for asymptomatic vs. mild intoxications (AUC 0.68, p=0.002). For all age groups it was 95 mg for no/mild symptoms vs.moderate/severe symptoms (AUC of 0.663, p = 0.030).Conclusion: Our analysis resulted in useful dose cut-off values for methylphenidate exposures to differentiate betweenasymptomatic and mild intoxications for adults (175 mg), adolescents (95 mg) and pupils (53 mg). Further research in largercohorts will be needed.