Page 26 Acute Pain Management

Cannabinoids
1. Current evidence does not support the use of cannabinoids in acute pain management
(S) but these drugs appear to be mildly effective when used in the treatment of chronic
neuropathic pain, including multiple sclerosis‐related pain (N) (Level I).
Glucocorticoids

1. Dexamethasone, compared with placebo, reduces postoperative pain, nausea and
vomiting, and fatigue (Level II).
Complementary and alternative medicines
SUMMARY effective in some acute pain states. Adverse effects and interactions with medications
 There is some evidence that some complementary and alternative medicines may be

have been described with complementary and alternative medicines and must be
considered before their use (N).

5. REGIONALLY AND LOCALLY ADMINISTERED ANALGESIC DRUGS

Local anaesthetics
1. Lignocaine is more likely to cause transient neurologic symptoms than bupivacaine,
prilocaine and procaine (N) (Level I [Cochrane Review]).

2. The quality of epidural analgesia with local anaesthetics is improved with the addition of
opioids (U) (Level 1).
3. Ultrasound guidance reduces the risk of vascular puncture during the performance of
regional blockade (N) (Level I).

4. Continuous perineural infusions of lignocaine (lidocaine) result in less effective analgesia
and more motor block than long‐acting local anaesthetic agents (U) (Level II).
5. There are no consistent differences between ropivacaine, levobupivacaine and
bupivacaine when given in low doses for regional analgesia (epidural and peripheral
nerve blockade) in terms of quality of analgesia or motor blockade (U) (Level II).

6. Cardiovascular and central nervous system toxicity of the stereospecific isomers
ropivacaine and levobupivacaine is less severe than with racemic bupivacaine (U) (Level
II).
7. Lipid emulsion is effective in resuscitation of circulatory collapse due to local anaesthetic
toxicity, however uncertainties relating to dosage, efficacy and side effects still remain
and therefore it is appropriate to administer lipid emulsion once advanced cardiac life
support has begun and convulsions are controlled (N) (Level IV).
 Case reports following accidental overdose with ropivacaine and bupivacaine suggest
that resuscitation is likely to be more successful with ropivacaine (U).

Opioids
1. Intrathecal morphine produces better postoperative analgesia than intrathecal fentanyl
after Caesarean section (U) (Level I).
2. Intrathecal morphine doses of 300 mcg or more increase the risk of respiratory
depression (N) (Level I).
3. Morphine injected into the intra‐articular space following knee arthroscopy does not
improve analgesia compared with placebo when administered after surgery (R) (Level I).

xxvi Acute Pain Management: Scientific Evidence