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of local anaesthetics and opioids) into the epidural space via an indwelling catheter (Macintyre et al. 2010). Giving analgesia epidurally is a particularly valuable technique for the prevention of postoperative pain in patients undergoing major thoracic, abdominal and lower limb surgery, and can sometimes be used to manage the pain associated with trauma. Commonly used opioids for epidural analgesia include fentanyl and diamorphine (Wheatley et al. 2001). Combinations of low concentrations of local anaesthetic agents and opioids have been shown to provide consistently superior pain relief compared with either drug alone (Macintyre and Schug 2007).

Subcutaneous analgesia

Opioids are often given subcutaneously to manage chronic cancer pain. More recently, there has been an increase in the use of subcutaneous opioids for postoperative pain control. Both PCA and nurse-administered opioid injections of morphine, diamorphine or oxycodone via an indwelling subcutaneous cannula have been used successfully to manage postoperative pain (Vijayan 1997). An advantage of giving analgesia subcutaneously is that it avoids the problems associated with maintaining intravenous access.

Intramuscular analgesia

Until the early 1990s, regular 3–4-hourly intramuscular injections of opioids such as pethidine and morphine were routinely used for the management of postoperative pain. Because alternative techniques such as PCA and epidural analgesia are now available, intramuscular analgesia is used less frequently. Some useful algorithms have been developed to give guidance on titrating intramuscular analgesia (Harmer and Davies 1998, Macintyre and Schug 2007). Absorption via this route may be impaired in conditions of poor perfusion (e.g. in hypovolaemia, shock, hypothermia or immobility). This may lead to inadequate early analgesia (the drug cannot be absorbed properly and reach the systemic circulation and forms a drug depot) and late absorption of the drug depot (where the drug has remained in the muscular tissue and is absorbed only once perfusion is restored) (Macintyre et al. 2010).

Nasal analgesia

It is suggested that the nasal route may be effective for a number of opioids (Hanks et al. 2004). Nasal diamorphine spray has been shown to provide effective pain relief in accident and emergency departments in children and teenagers who are experiencing acute pain. This approach is being investigated in adult cancer patients with acute, episodic pain (Hanks et al. 2004).

Preprocedural considerations

Pharmacological support

Non-opioid analgesics

Paracetamol and paracetamol combinations

The use of non-opioid analgesics such as paracetamol or paracetamol combined with a weak opioid such as codeine is recommended for managing pain following minor surgical procedures or when the pain following major surgery begins to subside (McQuay et al. 1997). Paracetamol can also be given rectally if the oral route is contraindicated. An intravenous preparation of paracetamol is now available and can provide effective analgesia after surgical procedures (Romsing et al. 2002). It is more effective and of faster onset than the same dose given enterally. The use of the intravenous form should be limited to patients in whom the enteral route cannot be used.

Paracetamol taken in the correct dose of not more than 4 g per day is relatively free of side-effects. When used in combination with codeine preparations, the most frequent side-effect is constipation.

Non-steroidal anti-inflammatory drugs

Non-steroidal anti-inflammatory drugs (NSAIDs) have been shown to provide better pain relief than paracetamol combinations for acute pain (McQuay et al. 1997). These drugs can be used alone or in combination with both opioid and non-opioid analgesics. Two commonly used NSAIDs are diclofenac, which can be administered by the oral, parenteral, enteral or rectal route, and ibuprofen, which is available only as an oral or enteral preparation. The disadvantage of both of these is that often side-effects such as coagulation problems, renal impairment and gastrointestinal