Routes of Opioid Analgesic Therapy in the Management of Cancer Pain

Routes of Opioid Analgesic Therapy in the Management of Cancer Pain



from Cancer Control: Journal of the Moffitt Cancer Center Rom A. Stevens, MD, and Salim M. Ghazi, MD, Northwestern University, Chicago, Ill (RAS), and MayoClinic, Jacksonville, Fla (SMG).





Abstract and Introduction

Abstract

Background:The availability of various routes of administration of opioid analgesics can be confusing whendetermining an appropriate, efficacious, and cost-effective regimen to manage cancer pain.

Methods:The indications, contraindications, and pharmacokinetic properties of oral, intravenous, subcutaneous,transdermal, transmucosal, rectal, and perispinal routes of opioid administration are reviewed.

Results: 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, theefficacy of that system to deliver acceptable analgesia, the ease of use for the patient and family, the potentialor actual complications associated with that system, and the cost.

Conclusions: Administering opioids to manage cancer pain requires knowledge of potency relative tomorphine and bioavailability of the route chosen. Changes in the route, dosage, or opioid used should beaccompanied with close patient follow-up.



The variety of options for the delivery of opioids inthe management of cancer pain can be confusing. Insome instances, there are clear indications for usingone preparation or delivery system over another.These indications may take into consideration the abilityof the patient to use a specific type of delivery system,the efficacy of that system to deliver acceptableanalgesia, the ease of use by the patient and his or herfamily, and the potential or actual complications associatedwith that system. Cost is another important considerationfor patients who must purchase their ownmedications. Increasingly, patients in managed caresystems may be limited in the choice of analgesics bytheir managed care organization, which may restrictaccess to certain medications based on their cost.

This article addresses the variety of deliveryoptions for opioids available for the management ofcancer pain, with emphasis on the indications, contraindications,and pharmacokinetic differences (eg,time to peak effect and bioavailability) among systems(Tables 1-3) and relative cost of the various systems(Table 4). The systems discussed are oral, intravenous,subcutaneous, transdermal, rectal, and transmucosal.Because of space considerations, the perispinal opioidsystems will be discussed only briefly in this article.This information is important in assisting the physicianchoose the most efficacious, cost-effective, anduser-friendly option for each patient with cancer pain.

All of the opioid analgesics discussed in this articleare potent mu-agonists. By binding to the mu-receptors,they exert analgesia and at the same time affectrespiration and gastrointestinal motility. Although themixed agonist-antagonist opioids (eg, butorphanol) aresometimes prescribed for chronic pain, they have noplace in the treatment of cancer pain because of theirantagonistic effects at the mu receptor. Likewise,"partial"mu-agonists (eg, buprenorphine) have a "ceilingeffect" of analgesia; dose escalation above a certainpoint does not enhance analgesia. These agents alsohave no role in the treatment of cancer pain. The weakmu-agonists, such as codeine, hydrocodone, andpropoxyphene, are usually found in combination withaspirin or acetaminophen. Taken in large daily doses,the aspirin or acetaminophen compound becomes thelimiting factor due to potential hepatic toxicity. Therefore,this article does not discuss the mixed agonist-antagonist,partial agonist, or weak mu-agonist opioidanalgesics. Discussion will be limited to the potent mu-agonistsopioids (eg, morphine, methadone, oxycodone,hydromorphone, fentanyl, and sufentanil). http://www.medscape.com/viewarticle/408974