Skin nociceptive block with pramoxine delivery by subcutaneous injection in rats

  • Pharmacol Rep. 2018 Dec;70(6):1180-1184. doi: 10.1016/j.pharep.2018.09.001.
An-Kuo Chou  1 ,  Chong-Chi Chiu  2 ,  Yu-Wen Chen  3 ,  Jhi-Joung Wang  4 ,  Ching-Hsia Hung  5
Affiliations
  • 1. Department of Anesthesiology, China Medical University Hospital, Taichung, Taiwan; School of Medicine, College of Medicine, China Medical University, Taichung, Taiwan.
  • 2. Department of General Surgery, Chi Mei Medical Center, Tainan and Liouying, Taiwan; Department of Electrical Engineering, Southern Taiwan University of Science and Technology, Tainan, Taiwan.
  • 3. Department of Medical Research, Chi-Mei Medical Center, Tainan, Taiwan; Department of Physical Therapy, College of Health Care, China Medical University, Taichung, Taiwan. Electronic address: [email protected].
  • 4. Department of Medical Research, Chi-Mei Medical Center, Tainan, Taiwan.
  • 5. Department of Physical Therapy, College of Medicine, National Cheng Kung University, Tainan, Taiwan; Institute of Allied Health Sciences, College of Medicine, National Cheng Kung University, Tainan, Taiwan.
PMID: 30326418 DOI: 10.1016/j.pharep.2018.09.001
Abstract

Background: Pramoxine has been shown to produce spinal anesthesia, while cutaneous analgesia (peripheral) of pramoxine is not established. The experimental goal was to examine cutaneous antinociception produced by a local anesthetic (LA) pramoxine and compare this result with that of another well-known LA lidocaine.

Methods: Cutaneous antinociception was evaluated by blockade of pinprick- induced cutaneous trunci muscle reflex (CTMR) on the skin of rat's back. After the dose-related curves were constructed, the quality and duration of drug's (lidocaine and pramoxine) cutaneous antinociception were compared.

Results: We showed that pramoxine, as well as lidocaine produced skin antinociception in a dose-related fashion. The relative potency (ED50 [50% effective dose] basis) was lidocaine (5.44 [4.67-6.35] μmol) greater than pramoxine (42.1 [38.8-45.7] μmol) (p < 0.01). On the basis of equianalgesic doses (ED75, ED50, and ED25), pramoxine caused equivalent duration of cutaneous antinociception to lidocaine.

Conclusions: These preclinical data indicated that pramoxine elicits skin antinociception dose-relatedly. Pramoxine exhibits a potency less than that of lidocaine while they have a comparable duration of skin antinociceptive action.

Keywords
Lidocaine; Pinpricks; Pramoxine; Skin antinociception; Subcutaneous injection.
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