Rectal, buccal, and sublingual narcotics for the management of cancer pain.

We review current knowledge on the rectal, buccal, and sublingual routes of narcotic administration as potential alternatives to oral, intramuscular, intravenous, and subcutaneous administrations of narcotics for the management of cancer pain. Most of the experience reported in the literature is based on the use of rectal, sublingual, and buccal narcotics for the management of acute pain syndromes. Preliminary evidence suggests that both morphine sulfate and chlorhydrate can be administered rectally because there is acceptable absorption with this route even if considerable interpersonal variation exists. There are no controlled trials on the long-term use of rectal morphine for cancer pain. There are very few reports on the clinical effects of sublingual and buccal morphine, and pharmacokinetic data are often debatable. There is evidence to justify further research into all three routes of narcotic administration. At the moment rectal use is justified in clinical trials in cancer patients, but there are not enough data on the pharmacokinetics of different narcotics when administered by the buccal or sublingual routes.