Choice of analgesics for children

Choice of analgesics in children

Pain has often been undertreated in infants and children because of fears of respiratory depression, cardiovascular collapse, depressed levels of consciousness, and addiction with potent opioid analgesics. Assessment of pain is also a problem in children of all ages and it is not that long since it was widely believed that neonates were incapable of feeling pain.

Non-opioid analgesics are used in infants and children, either alone for minor pain or as an adjunct to opioid analgesics in severe pain. Paracetamol is frequently used but it lacks any anti-inflammatory effect. NSAIDs such as ibuprofen are useful for pain associated with inflammation. The use of aspirin is greatly restricted by its association with Reye's syndrome.

The opioids are still the mainstay of analgesia for moderate to severe pain in paediatric patients, and morphine is the standard against which the others are compared. Continuous intravenous infusion with or without initial loading doses has become popular for postoperative pain relief, but titration of the infusion rate is necessary to achieve a balance between analgesia and respiratory depression (particular care is needed in neonates, see below). Subcutaneous infusions of morphine have also been used, mostly for the relief of terminal cancer pain in children. Intramuscular injections can provide excellent analgesia but are painful and therefore probably only suitable for short-term use. Fentanyl has also been widely used for short-term analgesia in surgical procedures, and a variety of other opioids have been given. Patient-controlled analgesia using morphine has been tried in children.

Morphine has also been given to children by the epidural route; experience with the intrathecal route is more limited. Other methods of opioid drug delivery of possible value in paediatric analgesia include transmucosal, nasal, and transdermal administration.

Local anaesthetics are especially suitable for the management of acute pain in day-care situations. Single injections given by the epidural route are often used to provide analgesia during and after surgery. Continuous epidural infusions of local anaesthetics have also been used. However, simpler techniques such as wound infiltration or peripheral nerve blocks can also provide effective analgesia for some procedures and are free of the problems of lower limb weakness or urinary retention associated with caudal blocks. Application of eutectic creams containing lidocaine with prilocaine to intact skin, to produce surface anaesthesia, may be sufficient for some minor painful procedures in children.

Ketamine is used in outpatients for brief, painful procedures such as fracture reduction and to provide immobility for repair of facial lacerations in young children. The emergence reactions that limit its use in adults are less common in children.

Most neonates requiring analgesia and receiving respiratory support can be managed with an infusion of morphine but in neonates who are breathing spontaneously there is a substantial risk of respiratory depression. Morphine has been used in such neonates but should be limited to those under intensive care, as for example after major surgery. Fentanyl citrate and codeine phosphate have also been used in neonates. Sucrose and other sweet tasting solutions have been shown to reduce physiologic and behavioural indicators of stress and pain in neonates undergoing painful procedures although there had been some doubt expressed over whether this indicates effective analgesia.