An overview of analgesics: NSAIDs, paracetamol, and topical analgesics (Part 1)

  • Roland Van Rensburg Stellenbosch University
  • Helmut Reuter Stellenbosch University
Keywords: Pain, nociception, NSAIDs, paracetamol, topical analgesia

Abstract

Pain is a complex and unique experience. It encompasses several pathways, involving nociceptive signal generation (transduction) and propagation (transmission), as well as perception and modulation of the nociceptive stimuli. Nonsteroidal anti-inflammatory drugs (NSAIDs) primarily exert their analgesic effects through inhibition of cyclooxygenase (COX) enzymes, thereby attenuating prostaglandin synthesis. The COX-2 selective NSAIDs (coxibs) and aspirin have also been shown to reduce colorectal cancers, presumably by prostaglandin-inhibition mechanisms. Paracetamol appears to have both peripheral and central effects. The postulated mechanism for its peripheral effects is indirect COX inhibition, while the central effects are thought to be mediated by modulation of descending pain inhibition pathways. Topical analgesics are available in various formulations. The topical NSAIDs have the same mechanism of action as the systemic formulations, but with less systemic absorption and effects. The local anaesthetics provide a dense sensory block via inhibition of nerve impulse transmission, and are available in percutaneous and transdermal preparations. Capsicum is effective for neuropathic pain, and acts by stimulating and then desensitising peripheral sensory nerves.

Author Biographies

Roland Van Rensburg, Stellenbosch University

Division of Clinical Pharmacology, Department of Medicine, Faculty of Medicine and Health Sciences, Stellenbosch University, Cape Town

Helmut Reuter, Stellenbosch University

Division of Clinical Pharmacology, Department of Medicine, Faculty of Medicine and Health Sciences, Stellenbosch University, Cape Town

Published
2019-01-23
Section
Review Articles