Page 118 Acute Pain Management

their opioid dose or after a change was made to another opioid (Angst & Clark, 2006; Chu LF et al,
2008), however there have been no similar reports from an acute pain setting.
Clinical implications and possible attenuation of tolerance and OIH
See Section 11.7.1.
Tolerance to adverse effects of opioids
Tolerance to the side effects of opioids also occurs; tolerance to sedation, cognitive effects,
nausea and respiratory depression can occur reasonably rapidly, but there is little if any
change in miosis or constipation (Chang et al, 2007).

Key messages
1. Dextropropoxyphene has low analgesic efficacy (U) (Level I [Cochrane Review]).
2. Tramadol is an effective treatment for neuropathic pain (U) (Level I [Cochrane Review]).
3. Gabapentin, non‐steroidal NSAIDs and ketamine are opioid‐sparing medications and
reduce opioid‐related side effects (N) (Level I).
4. In appropriate doses, droperidol, metoclopramide, ondansetron, tropisetron, dolasetron,
dexamethasone, cyclizine and granisetron are effective in the prevention of postoperative
CHAPTER 4 5. Alvimopan and methylnaltrexone are effective in reversing opioid‐induced slowing of
nausea and vomiting (N) (Level I [Cochrane Review]).

gastrointestinal transit time and constipation (N) (Level I [Cochrane Review]).
6. Droperidol, dexamethasone and ondansetron are equally effective in the prevention of
postoperative nausea and vomiting (U) (Level I).
7. Paired combinations of 5HT3 antagonist, droperidol or dexamethasone provide superior
prophylaxis of postoperative nausea and vomiting than either compound alone (N)
(Level I).
8. Naloxone, naltrexone, nalbuphine, droperidol and 5HT3 antagonists are effective
treatments for opioid‐induced pruritus (N) (Level I).
9. Opioids in high doses can induce hyperalgesia (N) (Level I).
10. Tramadol has a lower risk of respiratory depression and impairs gastrointestinal motor
function less than other opioids at equianalgesic doses (U) (Level II).

11. Pethidine is not superior to morphine in treatment of pain of renal or biliary colic (U)
(Level II).
12. Morphine‐6‐glucuronide is an effective analgesic (N) (Level II).
13. In the management of acute pain, one opioid is not superior over others but some opioids
are better in some patients (U) (Level II).
14. The incidence of clinically meaningful adverse effects of opioids is dose‐related (U)
(Level II).

15. High doses of methadone can lead to prolonged QT interval (N) (Level II).
16. Haloperidol is effective in the prevention of postoperative nausea and vomiting (N)
(Level II).
17. Opioid antagonists are effective treatments for opioid‐induced urinary retention (N)
(Level II).

70 Acute Pain Management: Scientific Evidence