Page 202 Acute Pain Management

Morphine (IR, oral) is effective in the treatment of acute pain. Following preloading with IV
morphine, morphine liquid 20 mg (initial dose 20 mg; subsequent doses increased by 5 mg if
breakthrough doses needed) every 4 hours with additional 10 mg doses as needed has been
shown to provide better pain relief after hip surgery than IM morphine 5 to 10 mg prn
(McCormack et al, 1993 Level II).
In comparison with IV morphine patient‐controlled analgesia (PCA) alone, regular 4‐hourly
administration of 20 mg but not 10 mg oral morphine reduced PCA morphine consumption but
there were no differences in pain relief or side effects (Manoir et al, 2006 Level II).
IR oral opioids such as oxycodone, morphine and tramadol have also been used as ‘step‐down’
analgesia after PCA, with doses based on prior PCA requirements (Macintyre & Schug, 2007) and
after epidural analgesia (Lim & Schug, 2001 Level II).
Controlled-release formulations
CR formulations also referred to as slow‐release (SR) or prolonged‐release, may take 3 to
4 hours or more to reach peak effect. In contrast and in most cases, the analgesic effect of the
IR opioid preparations will be seen within about 45 to 60 minutes. This means that rapid
titration to effect is easier and safer with IR formulations.
In general the use of CR opioid preparations as the sole agents for the early management of
acute pain is discouraged because of difficulties in short‐term dose adjustments needed for
titration. CR opioid preparations should only be used at set time intervals and IR opioids
should be used for acute and breakthrough pain, and for titration of CR opioids.
CR oral oxycodone comprises an IR component as well as the delayed‐release compound and
therefore has a more rapid onset of action than other CR agents. CR oxycodone may be
CHAPTER 6 2004 Level II). However, IR oxycodone 5 mg and paracetamol 325 mg given 6‐hourly led to
effective in the immediate management of acute pain (Sunshine et al, 1996 Level II; Kampe et al,
better pain relief than 10 mg CR oxycodone given 12‐hourly (Kogan et al, 2007 Level II). In
comparison with IV morphine PCA alone, CR oxycodone in addition to morphine PCA resulted
in improved pain relief and patient satisfaction after lumbar discectomy and a lower incidence
of nausea and vomiting, as well as earlier return of bowel function (Blumenthal et al, 2007
Level II). CR oral oxycodone was found to be effective as ‘step‐down’ analgesia after 12 to
24 hours of PCA morphine (Ginsberg et al, 2003 Level IV).
More recently, a combined formulation of CR oxycodone and naloxone has been studied.
Compared with CR oxycodone alone in patients with chronic non‐malignant back pain, the
combination formulation resulted in similar analgesic efficacy but less bowel dysfunction
(Vondrackova et al, 2008 Level II). The addition of naloxone may also discourage unauthorised
injection of the drug (see Suboxone in Section 11.8).

6.1.2 Non-selective non-steroidal anti-inflammatory drugs and
coxibs

A number of nsNSAIDs and coxibs have been shown to be effective as sole therapy in a variety
of acute pain settings (see Table 6.1). Those for which there is Level I evidence of efficacy
include: aspirin 600 to 1200 mg (Edwards, Oldman et al, 2000 Level I), ibuprofen 200 to 400 mg
(Derry et al 2009a Level I), piroxicam 20 to 40 mg (Edwards, Loke et al, 2000 Level I), valdecoxib 20
to 40 mg (Lloyd et al, 2009 Level I), naproxen (Derry et al, 2009b Level I), ketorolac (Smith et al, 2000
Level I), lumiracoxib 400mg (Roy et al, 2007 Level I), celecoxib 200 to 400 mg (Derry et al, 2008
Level I) and diclofenac 50 to 100 mg (Derry et al, 2009c Level I).
The NNTs of each of these drugs is listed in Table 6.1.

154 Acute Pain Management: Scientific Evidence