Opioid analgesics as noncompetitive N-methyl-D-aspartate (NMDA) antagonists

TY - JOUR

T1 - Opioid analgesics as noncompetitive N-methyl-D-aspartate (NMDA) antagonists

AU - Ebert, B

AU - Thorkildsen, C

AU - Andersen, S

AU - Christrup, Lona Louring

AU - Hjeds, H

PY - 1998/9/1

Y1 - 1998/9/1

N2 - Much evidence points to the involvement of N-methyl-D-aspartate (NMDA) receptors in the development and maintainance of neuropathic pain. In neuropathic pain, there is generally involved a presumed opioid-insensitive component, which apparently can be blocked by NMDA receptor antagonists. However, in order to obtain complete analgesia, a combination of an NMDA receptor antagonist and an opioid receptor agonist is needed. Recent in vitro data have demonstrated that methadone, ketobemidone, and dextropropoxyphene, in addition to being opioid receptor agonists, also are weak noncompetitive NMDA receptor antagonists. Clinical anecdotes suggest that the NMDA receptor antagonism of these opioids may play a significant role in the pharmacological action of these compounds; however, no clinical studies have been conducted to support this issue. In the present commentary, we discuss evidence for the NMDA receptor antagonism of these compounds and its relevance for clinical pain treatment; an overview of structure-activity relationships for the relevant opioids as noncompetitive NMDA receptor antagonists also is given. It is concluded that although the finding that some opioids are weak noncompetitive NMDA receptor antagonists in vitro has created much attention among clinicians, no clinical studies have been conducted to evaluate the applicability of these compounds in the treatment of neuropathic pain conditions.

AB - Much evidence points to the involvement of N-methyl-D-aspartate (NMDA) receptors in the development and maintainance of neuropathic pain. In neuropathic pain, there is generally involved a presumed opioid-insensitive component, which apparently can be blocked by NMDA receptor antagonists. However, in order to obtain complete analgesia, a combination of an NMDA receptor antagonist and an opioid receptor agonist is needed. Recent in vitro data have demonstrated that methadone, ketobemidone, and dextropropoxyphene, in addition to being opioid receptor agonists, also are weak noncompetitive NMDA receptor antagonists. Clinical anecdotes suggest that the NMDA receptor antagonism of these opioids may play a significant role in the pharmacological action of these compounds; however, no clinical studies have been conducted to support this issue. In the present commentary, we discuss evidence for the NMDA receptor antagonism of these compounds and its relevance for clinical pain treatment; an overview of structure-activity relationships for the relevant opioids as noncompetitive NMDA receptor antagonists also is given. It is concluded that although the finding that some opioids are weak noncompetitive NMDA receptor antagonists in vitro has created much attention among clinicians, no clinical studies have been conducted to evaluate the applicability of these compounds in the treatment of neuropathic pain conditions.

KW - Analgesics, Opioid

KW - Animals

KW - Binding, Competitive

KW - Dextropropoxyphene

KW - Excitatory Amino Acid Antagonists

KW - Humans

KW - Meperidine

KW - Methadone

KW - Receptors, N-Methyl-D-Aspartate

KW - Structure-Activity Relationship

M3 - Journal article

C2 - 9783723

SN - 0006-2952

VL - 56

SP - 553

EP - 559

JO - Biochemical Pharmacology

JF - Biochemical Pharmacology

IS - 5

ER -