Routes of opioid analgesic therapy in the management of cancer pain

The availability of various routes of administration of opioid analgesics can be confusing when determining an appropriate, efficacious, and cost-effective regimen to manage cancer pain. The indications, contraindications, and pharmacokinetic properties of oral, intravenous, subcutaneous, transdermal, transmucosal, rectal, and perispinal routes of opioid administration are reviewed. To determine the most efficacious, cost-effective, and user-friendly option to manage cancer pain, several factors must be considered: the ability of the patient to use a specific type of delivery system, the efficacy of that system to deliver acceptable analgesia, the ease of use for the patient and family, the potential or actual complications associated with that system, and the cost. Administering opioids to manage cancer pain requires knowledge of potency relative to morphine and bioavailability of the route chosen. Changes in the route, dosage, or opioid used should be accompanied with close patient follow-up.