الفهرس 
Pharmacology of opioids and Other CO AnalgesicsOnly 14 pages are availabe for public view
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Abstract
T
he number of patients on long term opioid therapy has been increasing over the last decade. chronic pain patients whether cancer or non cancer related have increased the use of opioids. While the prevalence of illicit opioid use has remained relatively stable, the diversion and abuse of prescription opioids has escalated, as has the number of individuals receiving methadone or buprenorphine pharmacotherapy for opioid addiction. As a result, the proportion of opioid-tolerant patients requiring acute pain management has increased, often presenting clinicians with greater challenges than those faced when treating the opioid-naïve.
Drug abuse patients can present to the anesthesiologists for a variety of reasons either emergency or elective or during labor or for trauma care. Opioid-dependent patients may present with organ damage, infectious diseases such as human immunodeficiency virus, tuberculosis, hepatitis, associated psychological disorders, and drug-specific adaptations such as tolerance, physical dependence, and withdrawal.
Pain management in opioid dependant patients is a challenging problem. The preoperative use of opioids has led to an uncontrolled pain in the postoperative period and therefore increased analgesic requirements. Anesthesiologists and other healthcare providers for such patients therefore should carefully identify chronically opioid consuming patients before surgery, manage opioids requirements optimally in the perioperative period, use adjuvant analgesic and anesthetic techniques, and formulate a plan in collaboration with the patient on how to return to the preoperative opioid dose.
Treatment aims include effective relief of acute pain, prevention of drug withdrawal, assistance with any related social, psychiatric and behavioural issues, and ensuring continuity of long-term care. Such patients require preoperative maintenance of their daily opioid dose and a multimodal analgesia strategy, including regional, local anesthesia, anti-inflammatory drugs and additional short acting opioids when needed. Moreover, other techniques including physical treatment approaches have been used in conjunction with pharmacological methods as a part of a multimodal approach.
Opioid rotation may be also useful. It is important to understand that equivalence conversion tables may not be efficient for all patients. Therefore, each patient has to be assessed and their medication titrated on an individual basis. Evidence suggests that PCA opioid doses can be expected to be significantly higher than in opioid naive patients requiring higher bolus doses, and possibly shortening of the lock out interval.
Although parenteral administration remains the choice, oral, transdermal and sublingual routes have been used. Patients on opioid maintenance programmes may benefit, in the acute phase, from polyopioid therapy, in which another opioid is added to their methadone or buprenorphine. Similarly, patients on transdermal opioids should continue with their patch treatment, and receive additional top-up pain relief.
Discharge planning should commence at an early stage and may involve the use of a ‘Reverse Pain Ladder’ aiming to limit duration of additional opioid use. Legislative requirements may restrict which drugs can be prescribed at the time of hospital discharge. At all stages, there should be appropriate and regular consultation and liaison with the patient, other treating teams and specialist services.