Drugs for pain (analgesics)

Analgesics are often used in a stepwise fashion to alleviate symptoms of pain. Conventional analgesics tend to be used in a stepwise fashion. Simple analgesics such as paracetamol being used first. Often regular paracetamol is sufficient to alleviate many types of pain. If regular paracetamol is not sufficient then other analgesics should be considered.

Non steroidal anti-inflammatory drugs (NSAIDs), such as brufen, ibuprofen, diclofenac (voltarol) can be very useful for musculoskeletal pain but tend to be less effective for gastro-intestinal disease, may provoke NSAID related small bowel or gastric ulceration. They may also rarely be associated with other significant adverse effects on the liver and the kidneys. In patients with inflammatory bowel disease NSAIDs may provoke relapse of the disease. This may occur in both Crohn’s and ulcerative colitis and usually relapse is triggered within a week of commencing the drug. It appears that in those patients who are susceptible relapse occurs which ever non-steroidal is used, this susceptibility appears to persist over time as well so these patients should avoid NSAIDs. In patients who have IBD and have previously tolerated NSAIDs it appears that they can be used safely.

Tramadol and codeine are opiate based analgesics used for moderate pain, both are rather stronger than paracetamol, but both can have adverse effects which include constipation, increased abdominal pain and nausea. They may also cause confusion, and drowsiness particularly in elderly patients. Other opiate analgesics may also be used in the setting of acute abdominal pain and can be exceedingly effective in relieving short term distress, however there is a growing body of evidence that their long-term use in chronic (long-term) abdominal pain may cause increasing bowel problems and worsening pain in a significant number of patients, furthermore a few patients may develop narcotic bowel syndrome. This is a condition where administration of opiates leads to worsening abdominal symptoms and pain, due to the fact that long-term opiate use may lead to opiate related hyperalgesia (enhanced pain perception) rather than pain relief. This arises as a result in changes in receptors and pathways within the visceral and central nervous system which can arise following opiate use. It may occur following surgery or commonly in the setting of functional abdominal conditions where opiates are sometimes initiated as an attempt to control difficult pain symptoms. The treatment for which is to institute an appropriate withdrawal program, with the support of both patient and physician, and where required further short term medication to reduce the side-effects of withdrawal.

A number of non opiate analgesics are also used to control pain in abdominal conditions. Tricyclic anti-depressants, such as amitriptyline (usually in doses of 10-30mg), in relatively low dose and SSRI’s have been demonstrated to have significant analgesic properties in patients with both malignancy and functional gastro-intestinal disease. These drugs may also have effects on bowel function and may cause drowsiness, dry mouth, acute retention and rarely confusion and unsteadiness. A number of anti-epileptics, such as pregabalin and gabapentin may also be used to control abdominal pain. These drugs appear particularly good in modulating nerve related pain and it is believed they work by reducing the firing of nerves related to pain perception. Once again they may cause drowsiness or confusion.