title: Tramadol half life is dose dependent in overdose.
abstract: BACKGROUND
  Tramalol overdose is disproportionately more common in Iran. In recent years, Tramadol overdose has become one of the most common causes of poisoning admissions to emergency departments in this country. To the best of our knowledge, there is little or no information regarding the toxicokinetic properties of Tramadol such as its half life. Given the fact that poisoning management should be based on the toxicokinetic of substances, we aimed at investigating the half life of Tramadol in man as a critical toxicokinetic variable in overdose.
  
  
  METHODS
  Blood samples of each patient were collected on admission and repeated later. Plasma was harvested after separation from blood cells by centrifugation and quantified using HPLC method. Calculations were performed on Tramadol blood concentration quantities.
  
  
  RESULTS
  Demographic: Most of cases were men (81.81%). Mean (Standard Deviation (SD), min-max) age was 23 (8.142, 17-40). Serum Tramadol levels: Mean (SD, min-max) first Tramadol concentration was 786.91 (394.53, 391-1495). Mean (SD, min-max) second Tramadol concentration was 433.09 (269.63, 148-950). Mean (SD, min-max) of Tramadol half life was calculated as 9.24 hour (2.310, 4.99-13.45) Associations: Half life was associated with higher concentrations (r=0.708 Sig=0.015).
  
  
  CONCLUSIONS
  We report the mean half life of tramadol in overdose to be 9.24 hours which is remarkably higher than that measured in previous pharmacokinetic studies. We also concluded that Tramadol half life is dose dependent in overdose which may explain the further consequences of severe overdoses.
authors.affiliation: Addiction Research Centre, Imam Reza (p) Hospital, Ibn-e-Sina Street, Mashhad University of Medical Sciences, Mashhad, 9133316791, Iran. Hkhosrojerdi7@gmail.com.
authors.forename: Hamid
authors.initials: H
authors.lastname: Khosrojerdi
authors.affiliation: Nanotechnology Research Centre, School of Pharmacy, Mashhad University of Medical Sciences, Mashhad, Iran. ghazaal.alipour@gmail.com.
authors.forename: Ghazal
authors.initials: G
authors.lastname: Alipour Talesh
authors.affiliation: Addiction Research Centre, Imam Reza (p) Hospital, Ibn-e-Sina Street, Mashhad University of Medical Sciences, Mashhad, 9133316791, Iran. toxdanay@gmail.com.
authors.forename: Gholam Hassan
authors.initials: GH
authors.lastname: Danaei
authors.affiliation: Nanotechnology Research Centre, School of Pharmacy, Mashhad University of Medical Sciences, Mashhad, Iran. ShokoohS871@mums.ac.ir.
authors.forename: Sara
authors.initials: S
authors.lastname: Shokooh Saremi
authors.affiliation: Addiction Research Centre, Imam Reza (p) Hospital, Ibn-e-Sina Street, Mashhad University of Medical Sciences, Mashhad, 9133316791, Iran. Adaba871@mums.ac.ir.
authors.forename: Afrouz
authors.initials: A
authors.lastname: Adab
authors.affiliation: Addiction Research Centre, Imam Reza (p) Hospital, Ibn-e-Sina Street, Mashhad University of Medical Sciences, Mashhad, 9133316791, Iran. AfshariR@mums.ac.ir.
authors.forename: Reza
authors.initials: R
authors.lastname: Afshari
mesh_terms: D000293:Adolescent; D000328:Adult; D000701:Analgesics, Opioid / Q000493:pharmacokinetics* / Q000506:poisoning; D003430:Cross-Sectional Studies; D062787:Drug Overdose / Q000097:blood / Q000209:etiology*; D005260:Female; D006207:Half-Life; D006801:Humans; D007492:Iran; D008297:Male; D011446:Prospective Studies; D014147:Tramadol / Q000493:pharmacokinetics* / Q000506:poisoning; D055815:Young Adult
chemical_list: D000701:Analgesics, Opioid; D014147:Tramadol