___
Raffa RB, Friderichs E, Reimann W, Shank RP, Codd EE, Vaught JL Opioid and nonopioid components indepen- dently contribute to the mechanism of action of tramadol, an 'atypical' opioid analgesic. J Pharmacol Exp Ther 1992; 260:275-285.
Lukas R, Grond S, Lehmann KA. A Risk-benefit assess- ment of tramadol in management of pain. Drug Safety 1996; 15(1):8-29.
Gold Standard, Inc. Tramadol. [Accessed on 12/16/08]; Clinical Pharmacology [database online] http://www.clinicalpharmacology.com
Rojas-Corrales MO, Gibert-Rahola J, Micó JA. Tramadol induces antidepressant-type effects in mice. Life Sci 1998; 63:175-180.
Yalcin I, Aksu F, Belzung C. Effects of desipramine and tramadol in a chronic mild stress model in mice are altered by yohimbine but not by pindolol. Eur J Pharmacol 2005; 514:165-174.
Shapira NA, Verduin ML, DeGraw JD Treatment of refrac- tory major depression with tramadol monotherapy. J Clin Psychiatry 2001; 62:205-206.
Faron-Gorecka A, Kusmider M, Inan SY, Siwanowicz J, Dziedzicka Wasylewska M Effects of tramadol on alpha2- adrenergic receptors in the rat brain. Brain Res 2004; 1016:263-267
Barber J. Examining the use of tramadol hydrochloride as an antidepressant. Exp Clin Psychopharmacol 2011; 19(2):123-130.
Hegerl U. Antidepressants and suicidality. Eur Arch Psychiatry Clin Neurosci 2006; 256:199-200.