Chlordiazepoxide Preventive Effect on Tramadol Overdose Induced Serotonin Syndrome Evaluated by Hunter and Radomski Criteria: A Clinical Trial

Introduction: Tramadol is an analgesic medication that is frequently abused. It has two functions; mu‑opioid receptors agonism, as well as, serotonergic activities. It has shown that tramadol overdose may induce serotonin syndrome (SS). This study evaluates whether early treatment with chlordiazepoxide could prevent SS in admitted tramadol overdoses. Materials and Methods: In this single blind randomized control trial, 50% of admitted tramadol overdoses in Imam Reza (p) Hospital from 21 September 2011 to 21 January 2012 were recruited. Cases received chlordiazepoxide and controls received placebo. Clinical findings were recorded in a pre‑designed spread sheet every 6 hours in the first 24 hours of admission. SS was determined by two independent methods; Hunter Criteria (HC) and Radomski Criteria (RC). Results: In total, five patients developed SS when HC or RC was taken into account. Among them, four cases were shared. None of the SS cases diagnosed with HC received chlordiazepoxide. However, just one SS case diagnosed with RC was from the case group. Based on HC, chlordiazepoxide decreased the Risk Ratio (CI 95%) of SS to 0.80 (0.66-0.97) (P = 0.025). This effect did not reach statistically significant levels when SS was diagnosed with RC. Conclusion: This study supports the fact that pre‑treatment with chlordiazepoxide could prevent tramadol overdose induced SS.