Antihyperalgesic activity of a novel synthesized analogue of lidocaine in diabetic rats

Objectives The purpose of this study was to assess the antinociceptive and antihyperalgesic effects of a lidocaine analogue N-(2,6-dichlorophenyl)-2-(4- methyl-1-piperidinyl)acetamide (LIA). Methods The structure of LIA was established by elemental analysis and compatible IR, ¹H NMR, ¹³C NMR, and spectral data. Nociceptive and hyperalgesic activity were evaluated in normoglycaemic and streptozocin-induced diabetic rats using the formalin test. Formalin-evoked flinching, an indication of nociception and hyperalgesia, was increased in diabetic rats (using 0.5% formalin) compared with nondiabetic rats (using 1% formalin). Key findings Local administration of LIA into the dorsal surface of the right hind paw (0.18-5.6 mg per paw) significantly reduced the formalin-induced nociceptive and hyperalgesic behaviour of nondiabetic and diabetic rat. The antinociceptive effect of LIA was higher than that of lidocaine injection, furthermore this effect was higher than that of gabapentin. Conclusions LIA may have potential as a treatment for diabetic hyperalgesia. Further investigations of the antinociceptive mechanisms and the safety of this new compound are necessary.