title: Tramadol Induced QTc-Interval Prolongation: Prevalence, Clinical Factors and Correlation to Plasma Concentrations.
abstract: In recent years, several cases of torsade de pointes have been associated with many opioids. However, to present no cases have been reported with tramadol.
  
  
  
  To evaluate the effect of tramadol on QT-interval in the clinical setting.
  
  
  
  Medical history and comorbidities predisposing to QT interval prolongation were registered for patients requiring medical assistance that involved tramadol administration. Ionograms and ECGs were performed at baseline and intratreatment; QT interval was analyzed after correction with Bazzet, Fridericia, Framinghan and Hogdes formula.
  
  
  
  115 patients were studied (50.4% males) All patients had received tramadol 150-400 mg/day during 3.0-5.0 days at the moment of intratreatment control. Plasma concentrations of tramadol were 201-1613 ng/mL. Intratreatment electrocardiographic control, as mean ± SD (range), showed QTcB 372±32 (305 to 433), QTcFri 356±37 (281 to 429), QTcFra 363±33 (299 to 429), QTcH 362±30 (304 to 427), ΔQTcB 26±40 (-73 to 110), ΔQTcFri 24±48 (-97 to 121), ΔQTcFra 22±42 (-81 to 109) and .QTcH 22±38 (-68 to 110) ms. QTc interval presents high correlation with plasma tramadol concentrations (for .QTc, R>0.77). Renal failure was associated with a relative risk for ΔQTc > 30 ms of 1.90 (IC95% 1.31-2.74) and for ΔQTc > 60 ms of 4.74 (IC95% 2.57-8.74). No patient had evidence of arrhythmia during the present study.
  
  
  
  Tramadol produces QTc interval prolongation in good correlation with plasma drug concentrations; renal failure is a risk factor for higher concentration and QT prolongation by tramadol.
authors.affiliation: Department of Pharmacology, School of Medicine, University of Buenos Aires, Paraguay 2155 - Piso 16, C1121ABG Ciudad Autónoma de Buenos Aires, Argentina. gkeller@fmed.uba.ar.
authors.forename: Guillermo A
authors.initials: GA
authors.lastname: Keller
authors.forename: María C V
authors.initials: MC
authors.lastname: Etchegoyen
authors.forename: Nicolás
authors.initials: N
authors.lastname: Fernandez
authors.forename: Nancy M
authors.initials: NM
authors.lastname: Olivera
authors.forename: Patricia N
authors.initials: PN
authors.lastname: Quiroga
authors.forename: Waldo H
authors.initials: WH
authors.lastname: Belloso
authors.forename: Roberto A
authors.initials: RA
authors.lastname: Diez
authors.forename: Guillermo
authors.initials: G
authors.lastname: Di Girolamo
mesh_terms: D000368:Aged; D000369:Aged, 80 and over; D000701:Analgesics, Opioid / Q000009:adverse effects* / Q000097:blood*; D001118:Argentina / Q000453:epidemiology; D015331:Cohort Studies; D004562:Electrocardiography / Q000187:drug effects; D005260:Female; D006801:Humans; D008133:Long QT Syndrome / Q000097:blood* / Q000139:chemically induced* / Q000453:epidemiology; D008137:Longitudinal Studies; D008297:Male; D008875:Middle Aged; D015995:Prevalence; D011446:Prospective Studies; D014147:Tramadol / Q000009:adverse effects* / Q000097:blood*
chemical_list: D000701:Analgesics, Opioid; D014147:Tramadol