Visceral Pain
When evaluating cramping, colicky abdominal pain, especially in a patient using opioids, consider urinary retention and fecal impaction. Once these have been evaluated, if visceral pain does not respond to an opioid alone, an anticholinergic drug such as oxybutynin, scopolamine, glycopyrrolate, or hyoscyamine can be used.
Oxybutynin will be particularly useful in a patient with bladder spasms, while hyoscyamine suppositories (a belladona alkaloid) can also be useful in a patient with rectal spasms. Anticholinergic medications may also be useful in the patient with intestinal colic or increased intestinal secretions secondary to an inoperable obstruction.
The patient should be aware of the potential side effects: increased constipation, dry mouth, or blurred vision. The patient's laxative regimen may need to be increased to ensure regular bowel movements.
If the patient cannot swallow tablets, consider transdermal scopolamine. Glycopyrrolate can also be combined with an opioid and administered by subcutaneous (SC) infusion.
In addition to the anticholinergic agents discussed above, atropine (SC, IV, or oral) can help relieve spasmodic, colicky pain due to bowel-wall distension. Octreotide, a somatostatin analog, can also be administered as an SC injection or as a continuous infusion, though cost is significant.
Corticosteroids may also provide pain relief by reducing edema and inflammation.
Intractable symptoms may require continuous or intermittent gastric decompression via nasogastric tube. The relative discomfort of bowel obstruction symptoms must be weighed against the discomfort of a nasogastric tube.