PMID- 9520235
OWN - NLM
STAT- MEDLINE
DCOM- 19980504
LR  - 20220408
IS  - 0304-3959 (Print)
IS  - 0304-3959 (Linking)
VI  - 74
IP  - 2-3
DP  - 1998 Feb
TI  - Dose-response relationship of opioids in nociceptive and neuropathic 
      postoperative pain.
PG  - 205-11
AB  - The treatment of neuropathic pain with opioid analgesics is a matter of 
      controversy among clinicians and clinician scientists. Although neuropathic pain 
      is usually believed to be only slightly responsive to opioids, several studies 
      show that satisfactory analgesia can be obtained if adequate doses are 
      administered. In the present study, we tested the effectiveness of buprenorphine 
      in 21 patients soon after thoracic surgery (nociceptive postoperative pain) and 1 
      month after surgery in the same 21 patients who developed postthoracotomy 
      neuropathic pain with a burning, electrical and shooting quality. According to a 
      double-blind randomized study, the analgesic dose (AD) of buprenorphine needed to 
      reduce the long-term neuropathic pain by 50% (AD50) was calculated and compared 
      to the AD50 in the immediate postoperative period. We found that long-term 
      neuropathic pain could be adequately reduced by buprenorphine. However, the AD50 
      in neuropathic pain was significantly higher relative to the AD50 in the 
      short-term postoperative pain, indicating a lower responsiveness of neuropathic 
      pain to opioids. We also found a strict relationship between the short-term and 
      long-term AD50, characterized by a saturating effect. In fact, if the AD50 soon 
      after surgery was low, the AD50 increase in the long-term neuropathic pain was 
      threefold. By contrast, if the AD50 soon after surgery was high, the AD50 in 
      neuropathic pain was only slightly increased. This suggests that, though 
      neuropathic pain is indeed less sensitive to opioids, in some neuropathic 
      patients a large amount of opioid resistance is already present in other painful 
      conditions.
FAU - Benedetti, F
AU  - Benedetti F
AD  - Department of Neuroscience, University of Torino Medical School, Italy. 
      benedett@medfarm.unito.it
FAU - Vighetti, S
AU  - Vighetti S
FAU - Amanzio, M
AU  - Amanzio M
FAU - Casadio, C
AU  - Casadio C
FAU - Oliaro, A
AU  - Oliaro A
FAU - Bergamasco, B
AU  - Bergamasco B
FAU - Maggi, G
AU  - Maggi G
LA  - eng
PT  - Clinical Trial
PT  - Journal Article
PT  - Randomized Controlled Trial
PL  - United States
TA  - Pain
JT  - Pain
JID - 7508686
RN  - 0 (Analgesics, Opioid)
RN  - 40D3SCR4GZ (Buprenorphine)
SB  - IM
MH  - Aged
MH  - Analgesics, Opioid/*administration & dosage
MH  - Buprenorphine/*administration & dosage
MH  - Dose-Response Relationship, Drug
MH  - Double-Blind Method
MH  - Female
MH  - Humans
MH  - Male
MH  - Middle Aged
MH  - Nociceptors/*drug effects
MH  - Pain Threshold
MH  - Pain, Postoperative/*drug therapy
MH  - Peripheral Nerve Injuries
MH  - Skin/innervation
MH  - Thoracotomy
MH  - Time Factors
EDAT- 1998/03/31 00:00
MHDA- 1998/03/31 00:01
CRDT- 1998/03/31 00:00
PHST- 1998/03/31 00:00 [pubmed]
PHST- 1998/03/31 00:01 [medline]
PHST- 1998/03/31 00:00 [entrez]
AID - 10.1016/s0304-3959(97)00172-3 [doi]
PST - ppublish
SO  - Pain. 1998 Feb;74(2-3):205-11. doi: 10.1016/s0304-3959(97)00172-3.