Laser-evoked potentials as a tool for assessing the efficacy of antinociceptive drugs

• Published in: European journal of pain 2010-02, Vol.14 (2), p.222-225
• Main Authors: Truini, A, Panuccio, G, Galeotti, F, Maluccio, M.R, Sartucci, F, Avoli, M, Cruccu, G
• Format: Article
• Language: English
• Subjects: Adult; Analgesics - antagonists & inhibitors; Analgesics - therapeutic use; Analgesics, Opioid - antagonists & inhibitors; Analgesics, Opioid - therapeutic use; Anesthesia & Perioperative Care; Cingulate cortex; Cross-Over Studies; Double-Blind Method; Electroencephalography - drug effects; Evoked Potentials - drug effects; Female; Humans; Insula; Laser-evoked potentials; Lasers; Male; Naloxone - pharmacology; Narcotic Antagonists - pharmacology; Opioid; Pain - diagnosis; Pain - drug therapy; Pain Measurement - methods; Pain Medicine; Tramadol; Tramadol - antagonists & inhibitors; Tramadol - therapeutic use
• ISSN: 1090-3801; 1532-2149
• DOI: 10.1016/j.ejpain.2009.05.001

Abstract Laser-evoked potentials (LEPs) are brain responses to laser radiant heat pulses and reflect the activation of Aδ nociceptors. LEPs are to date the reference standard technique for studying nociceptive pathway function in patients with neuropathic pain. To find out whether LEPs also provide a useful neurophysiological tool for assessing antinociceptive drug efficacy, in this double-blind placebo-controlled study we measured changes induced by the analgesic tramadol on LEPs in 12 healthy subjects. We found that tramadol decreased the amplitude of LEPs, whereas placebo left LEPs unchanged. The opioid antagonist naloxone partially reversed the tramadol-induced LEP amplitude decrease. We conclude that LEPs may be reliably used in clinical practice and research for assessing the efficacy of antinociceptive drugs.