Techniques of opioid administration

Opioid medication is the first-line treatment for severe acute pain. Traditional methods of opioid administration remain in common use today (oral, rectal, intramuscular injection, subcutaneous injection). The key to achieving more effective pain relief with these techniques is to individualize treatment regimens for each patient. Using treatment algorithms to guide the administration of opioids has increased in popularity and can lead to significant improvements in pain management. Some examples of these are given. The most reliable indicator of opioid dose is the age of the patient, because age-related changes in pharmacokinetics and pharmcodynamics influence the dose of opioid required for analgesia. The key principle is titration of dose against effect, while minimizing the common adverse effects often associated with opioid administration. Other methods of opioid administration (intravenous bolus and/or infusion) are often limited to specialized areas, where patients are more closely monitored, to prevent the onset of serious opioid-related side-effects. Intravenous patient-controlled analgesia (PCA) is commonplace in many postoperative settings, allowing the patient, rather than the healthcare practitioner, to self-administer a pre-determined dose within the constraints of a lockout period. Several commonly prescribed PCA variables are listed. More advanced methods of opioid administration (epidural, intrathecal, transmucosal, transdermal) are also discussed. Intra-articular opioid administration is currently limited to orthopaedic surgery, having shown some positive effect in the relief of postoperative pain following knee arthroplasty. Iontophoresis is a newer method of transdermal administration that facilitates variation in the drug delivery rate not possible with previously available transdermal patches.