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Cost of PCA
The use of any analgesic technique, even if it is known to provide more effective pain relief,
also requires consideration of the cost involved. There are no good, consistent data on the
cost‐effectiveness of PCA compared with conventional opioid analgesic techniques;
information that is available often does not include the full scope of costs (eg cost of adverse
events or failure of an analgesic technique as well as the more obvious costs of pumps,
disposables and nursing time). However, in general, PCA comes at a higher cost because of
the equipment, consumables and drugs required; nursing time needed is much less (Jacox et al,
1997; Choiniere et al, 1998 Level II; Rittenhouse & Choiniere, 1999; Chang et al, 2004 Level II). PCA was
more cost‐effective than epidural analgesia after major abdominal surgery (Bartha et al, 2006).

7.1.2 Drugs used for parenteral PCA

Opioids
In general there is little evidence, on a population basis, to suggest that there are any major
differences in efficacy or the incidence of side effects between morphine and other opioids
commonly used in PCA, although the results of individual studies are inconsistent.
Pethidine
Compared with morphine, pethidine (meperidine) may lead to less effective pain relief on
movement (Bahar et al, 1985 Level II; Sinatra et al, 1989 Level II; Plummer et al, 1997 Level II);
no difference in nausea and vomiting (Bahar et al, 1985 Level II; Stanley et al, 1996 Level II;
Woodhouse et al, 1996 Level II; Plummer et al, 1997 Level II); and less sedation (Sinatra et al,
1989 Level II) and pruritus (Sinatra et al, 1989 Level II; Woodhouse et al, 1996 Level II).
Fentanyl
There was no difference between morphine and fentanyl in terms of pain relief (Howell et al,
CHAPTER 7 1995 Level II; Woodhouse et al, 1996 Level II) or the incidence of most side effects (Howell et al,
1995 Level II; Woodhouse et al, 1996 Level II); pruritus was more common with morphine
(Woodhouse et al, 1996 Level II).

Tramadol
Tramadol by PCA had a similar analgesic effect compared with morphine (Erolcay & Yuceyar,
2003 Level II; Unlugenc, Vardar et al, 2008 Level II), pethidine (Unlugenc, Vardar et al, 2008 Level II)
and oxycodone (Silvasti et al, 1999 Level II). The majority of studies showed that the incidence
of nausea and vomiting was no higher than with pure agonist opioids (Silvasti et al, 1999 Level II;
Erolcay & Yuceyar, 2003 Level II; Unlugenc, Vardar et al, 2008 Level II). Tramadol also had a lower risk
of respiratory depression and less effect on gastrointestinal motor function compared with
other opioids (see Section 4.1.2).
Other comparisons
Other comparisons with morphine include hydromorphone (no difference in pain relief or side
effects) (Rapp et al, 1996 Level II; Hong et al, 2008 Level II), oxycodone (no difference in pain relief
or side effects) (Silvasti et al, 1998 Level II) and piritramide (equally effective and similar side
effects) (Dopfmer et al, 2001 Level II).
Remifentanil provided at least equivalent analgesia compared with morphine (Kucukemre et al,
2005 Level II; Gurbet et al, 2004 Level II) and fentanyl PCA (Gurbet et al, 2004 Level II) and may be
associated with less nausea and vomiting (Kucukemre et al, 2005 Level II; Gurbet et al, 2004
Level II).

172 Acute Pain Management: Scientific Evidence