Finally, there are reports of the antipsychotic agent olanzapine being dramatically effective for this indication. Most opioid-induced constipation can be prevented by early use of cathartic agents, such as senna or lactulose. It is important to note that mere stool softeners, such as docusate, are less likely to be effective. For those rare patients for whom constipation remains intractable or a dose-limiting side effect, there may be a benefit in switching to transdermal fentanyl. However, there is little reason to establish an IV line just to deliver an opioid analgesic.
Subcutaneous delivery works as well, with far less difficulty in maintaining parenteral access.
But there are clearly patients who do not do well with drug delivery by other routes, usually due to dose-limiting side effects, who do better with spinal therapy. The epidural route has fewer complications when the likely duration of therapy is brief, that is a few weeks. In homebound hospice patients, sublingual application of high concentration oral morphine solution can allow ongoing analgesia and prevention of withdrawal during the last days of life, when the patient is often unable to swallow. Also, there are reports of sustained-release opioids being given rectally or even vaginally for that same purpose. Transbuccal administration of fentanyl gives very rapid onset of analgesia, and may be the drug of choice for predictable incident pain, such as that associated with dressing changes, or walking to a commode.