If the oral route is impractical or unavailable, rectal and transdermal administration are minimally invasive alternatives . Rectal is an alternative route for patients experiencing nausea and vomiting or fasting. Neutropenia and thrombocytopenia are relative contraindications. This route is not useful in the presence of diarrhea or among those who are physically unable to insert the suppository. Colostomy or similar stoma can be used provided the flow of effluent is slow enough to allow absorption.
Transdermal administration bypasses gastrointestinal absorption.
Therefore, a transdermal system is inappropriate for rapid dose titration and only considered in non-opioid naive patients who have relatively stable pain. As with controlled release opioids, immediate release opioids should be provided for the treatment of breakthrough pain. Transnasal is an alternative route when the oral route is unavailable. The transnasal route provides for rapid absorption and action. It is primarily used in the treatment of acute headaches.