Effects of perineural tramadol on nerve conduction of sural nerve

• Published in: Aǧrı Vol. 23; no. 2; pp. 51 - 56
• Main Authors: Beyazova, Mehmet, Öztürk, Ertan, Zinnuroğlu, Murat, Gökyar, Ismail, Babacan, Avni, Kaya, Kadir
• Format: Journal Article
• Language: English
• Published: Turkey 01.04.2011
• Subjects: Adult; Analgesics, Opioid - administration & dosage; Analgesics, Opioid - pharmacology; Dose-Response Relationship, Drug; Double-Blind Method; Humans; Male; Neural Conduction - drug effects; Sural Nerve - drug effects; Sural Nerve - physiology; Tramadol - administration & dosage; Tramadol - pharmacology; Treatment Outcome
• ISSN: 1300-0012
• DOI: 10.5505/agri.2011.72792

The aim of this study was to investigate whether tramadol had a dose-dependent blocking effect on nerve conduction when administered perineurally to the sural nerve of healthy volunteers. Twenty-four informed healthy subjects were randomized into four equal groups [Saline (placebo), 0.5% tramadol, 1% tramadol and 1.5% tramadol]. The study was designed to be double-blinded. Sensory nerve action potentials were recorded electroneurographically. Two milliliters of study solution was administered to the sural nerve perineurally at the level of the ankle with the guidance of a nerve stimulator. A sensory block was assumed to have developed when the amplitude of the averaged sensory nerve action potentials diminished below 80% of the baseline value in the subsequent recordings. According to the electroneurographical recordings, none of the volunteers in the saline group had block. However, the block rates with 0.5%, 1% and 1.5% tramadol were 1/6, 4/6 and 6/6, respectively (p<0.05). The maximum decrement in the sensory action potential amplitudes with respect to baseline amplitudes (given as median values) were as follows: 7.8% with saline; 12.5% with 0.5% tramadol; 38.5% with 1% tramadol; and 77.5% with 1.5% tramadol (p<0.05). While the median duration of sensory block with 0.5% tramadol was 5 minutes, it was 15 minutes with 1% tramadol and 35 minutes with 1.5% tramadol. Perineurally administered tramadol blocks sensory nerve conduction of the sural nerve in a dose-dependent manner.