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.
Objective: To evaluate the effect of tramadol on QT-interval in the clinical setting.
Research Design and Methods: 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.
Results: 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
Conclusion: 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.