Page 469 Acute Pain Management

Drug Comments Recommendations References
NB doses must still be
titrated to effect for each
patient
Other drugs
Local Amide‐type local anaesthetics Limited data: dose AMH, 2008
anaesthetics undergo hepatic metabolism and adjustment may be Bodenham &
clearance may be reduced in required with prolonged Park, 1990
hepatic disease or repeated use Jokinen, 2005
Increased plasma concentrations Jokinen et al,
of ropivacaine after continuous 2007
infusion but not single dose
Paracetamol Metabolised in the liver; small Commonly suggested AMH, 2008
proportion metabolised to the that it should be used Benson et al, 2005
potentially hepatotoxic with caution or in Graham et al,
metabolite N‐acetyl‐p‐ reduced doses or 2005
benzoquinonemine. This is frequency with active Zapater et al,
normally inactivated by hepatic liver disease, alcohol‐ 2004
glutathione. related liver disease and
Clearance is reduced glucose‐6‐phosphate
dehydrogenase deficiency
However, others report
that it can be used safely
in patients with liver
disease and is preferred
to NSAIDs, and that
therapeutic doses of
paracetamol, at least for
short‐term use, are an
unlikely cause of
hepatotoxicity in patients
who ingest moderate to
large amounts of alcohol
Tricyclic Amitriptyline is metabolised in Reduce dose if hepatic AMH, 2008
antidepressants the liver to nortriptyline, the impairment is severe
active agent
Carbamazepine Transient rises in hepatic Dose adjustment may be Ahmed & Siddiqi,
enzymes occur in 25%–61% of required; use not 2006
patients treated; has been recommended in severe AMH, 2008
reported to cause hepatic failure hepatic impairment CHAPTER 11
(rare)
Primarily metabolised in the liver
Valproate Transient rises in hepatic Dose adjustment may be Ahmed & Siddiqi,
enzymes occur in 10‐15% of required; use not 2006
patients treated; has been recommended in severe AMH, 2008
reported to cause hepatic failure hepatic impairment
(rare)
Primarily metabolised in the liver

Acute pain management: scientific evidence 421