title: Morphine/Codeine Ratio, a Key in Investigating a Case of Doping.
abstract: BACKGROUND
  Consumption of codeine can lead to positive urine test for morphine in athletes. Morphine is classified as a prohibited doping drug while Codeine is not. Morphine/codeine ratio is used in forensic medicine to distinguish the consumption of codeine from abuse of morphine and other narcotics.
  
  
  METHODS
  We present an athlete with positive urine test for morphine with a history of consumption of codeine. The disciplinary committee came to conclusion that the athlete had not consumed morphine and did not violate doping code based on morphine/codeine ratio.
  
  
  CONCLUSIONS
  Analysis of codeine to morphine metabolism rate is needed when we are using morphine/codeine ratio to rule out abuse of narcotics. WADA should consider analysis for the CYP2D6 alleles (main metabolizer of codeine) in case of including morphine/codeine ratio in future prohibited list. The possibility of ultra-rapid CYP2D6 cannot be ruled out in certain results of morphine/codeine near the cut point.
authors.affiliation: Sports Medicine Research Center, Tehran University of Medical Sciences, Tehran, IR Iran ; Iran Football Medical Assessment and Rehabilitation Center (IFMARC), Tehran, IR Iran.
authors.forename: Tohid
authors.initials: T
authors.lastname: Seif-Barghi
authors.affiliation: Iran Football Medical Assessment and Rehabilitation Center (IFMARC), Tehran, IR Iran ; Sports Medicine Department, Rasool Akram Hospital, Iran University of Medical Sciences, Tehran, IR Iran.
authors.forename: Navid
authors.initials: N
authors.lastname: Moghadam
authors.affiliation: Department of Medicinal Chemistry, School of Pharmacy, Shahid Beheshti University of Medical Sciences, Tehran, IR Iran.
authors.forename: Farzad
authors.initials: F
authors.lastname: Kobarfard
keywords: CYP2D6; Codeine; Doping in Sports; Morphine