Intrathecal pramoxine causes long-lasting spinal sensory and motor block in rats

  • J Pharm Pharmacol. 2018 Apr;70(4):543-549. doi: 10.1111/jphp.12894.
An-Kuo Chou  1  2 ,  Chong-Chi Chiu  3  4 ,  Ming-Ming Han  5 ,  Yu-Wen Chen  6  7 ,  Jhi-Joung Wang  6 ,  Ching-Hsia Hung  8  9
Affiliations
  • 1. Department of Anesthesiology, China Medical University Hospital, Taichung, Taiwan.
  • 2. School of Medicine, College of Medicine, China Medical University, Taichung, Taiwan.
  • 3. Department of General Surgery, Chi Mei Medical Center, Tainan and Liouying, Taiwan.
  • 4. Department of Electrical Engineering, Southern Taiwan University of Science and Technology, Tainan, Taiwan.
  • 5. Department of Anesthesiology, Anhui Provincial Hospital, Anhui Medical University, Hefei, China.
  • 6. Department of Medical Research, Chi-Mei Medical Center, Tainan, Taiwan.
  • 7. Department of Physical Therapy, College of Health Care, China Medical University, Taichung, Taiwan.
  • 8. Department of Physical Therapy, College of Medicine, National Cheng Kung University, Tainan, Taiwan.
  • 9. Institute of Allied Health Sciences, College of Medicine, National Cheng Kung University, Tainan, Taiwan.
PMID: 29441574 DOI: 10.1111/jphp.12894
Abstract

Objectives: The objective of this experiment was to investigate spinal anaesthetic effects of pramoxine and its comparison with bupivacaine, a long-lasting local anaesthetic.

Methods: After intrathecal injection, three neurobehavioural assessments, which consisted of nociceptive, proprioceptive and motor block, were constructed in rats. The effects of bupivacaine and pramoxine (four doses of each drug) in a dose-related manner were conducted to obtain the ED50 (50% effective dose). Pramoxine potency and duration at provoking spinal nociceptive, proprioceptive and motor block were compared with those of bupivacaine.

Key findings: We manifested that pramoxine provoked dose-relatedly spinal blockades of nociception, proprioception and motor function. Based on the ED50 , the rank potency at producing spinal nociceptive, proprioceptive and motor block was bupivacaine (0.90 (0.82-1.02), 1.00 (0.92-1.08) and 1.16 (1.02-1.34) μmol/kg) greater (P < 0.01 for the differences) than pramoxine (15.47 (14.04-17.05), 16.46 (15.06-17.99), and 17.77 (16.48-19.15) μmol/kg). The spinal block duration created by bupivacaine was not predominantly different (P > 0.05 for the differences) from that created by pramoxine at the equipotent doses (ED75 , ED50 and ED25 ).

Conclusions: Our preclinical experiment indicated that pramoxine elicited a dose-related spinal block, was less potent than bupivacaine and had a similar duration of spinal block compared with bupivacaine.

Keywords
bupivacaine; motor function; nociception; pramoxine; spinal block.
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