Perioperative opioids: Are they indispensable?

Perioperative pain is the most common cause of fear in patients undergoing surgical procedures under general anesthesia.[1] For ensuring a good patient experience with enhanced functional recovery, perioperative pain must be addressed satisfactorily. For many decades, opioids have been an integral component of balanced anesthesia care for their high analgesic efficacy. However, because of the several problems like opioid dependence, addiction, and drug abuse, (reported mainly from the western world, possibly because of the over prescription of opioids with limited oversight) and other side effects (respiratory depression, constipation, and nausea), has led to debate, and the introduction of new strategies like ‘opioid-sparing anesthesia’ and ‘opioid-free anesthesia’ techniques. The enhanced recovery after surgery program also recommends procedure-specific pain management strategies with particular attention to opioid-sparing.[2]

‘Opioid free anesthesia’ includes the administration of several non-opioid analgesics (acetaminophen, nonsteroidal anti-inflammatory drugs (NSAIDs) or cyclooxygenase-2 inhibitors, neuraxial or regional analgesic techniques, and nonpharmacologic methods) plus some of the analgesic adjuncts (gabapentinoids, steroids, and infusion of intravenous lidocaine, ketamine, dexmedetomidine, magnesium, and β-blocker).[34] The limitations of these techniques include ceiling effect with a small therapeutic index of safety for most of the drugs, inability to titrate the fixed-dose infusion to an effect, non-availability of objective monitoring for nociception in a patient under general anesthesia, and optimal combination of these agents or their dosing remaining unclear.[56] Above all, none of the drug combinations or techniques have been found to be superior to opioid-based analgesia. Till now, no new drugs or techniques have replaced opioids for the management of perioperative pain because of the strategic location of μ receptors (distributed throughout the pain pathway) and the role of the endogenous opioid system in regulating pain sensitivity.[7] Considering this, and the fact that poorly controlled perioperative pain is the most important independent predictor of transition from acute pain to chronic pain, the ‘opioid-free anesthesia’ technique seems difficult to practice.

‘Opioid sparing techniques’ (the multimodal analgesia wherein traditional opioid doses are reduced) is a feasible step to adequately control the postoperative pain and minimize adverse effects from individual agents. Initially, advocated to control the postoperative pain, the use of the multimodal analgesia technique has been extended to the entire perioperative period with the objective to reduce the opioid requirement.[89] The theoretical advantage of decreasing intraoperative opioid include a reduction in the dose-related perioperative adverse opioid effects as well as opioid-induced hyperalgesia.[1011] Although the multimodal analgesia technique seems feasible, its impact on the incidence of persistent opioid use after surgery and improvement in important anesthetic outcomes are still unknown.

We are not aware of the magnitude of the problem of opioid dependence after perioperative prescriptions in India. Postoperative analgesia in most Indian hospitals is left to surgeons, who generally avoid the use of morphine/fentanyl. The lack of awareness on the magnitude of the problem in India could be due to insufficient follow-up of the patients postoperatively and under-reporting. The ‘not so easily’ available opioids, leading to widespread use of NSAIDs with weak or synthetic opioids in India suggests that the opioid-related problems could be much less severe compared to the western world. Even so, there is on-going research work, and publications addressing the issue. A systemic review on ‘opioid-free onco-anesthesia’ was published in the JOACP some time back[12] but the authors primarily focused on the opioid-induced immune suppression only. In the current issue of JAOCP, a narrative review on ‘opioid-sparing strategies’ other than regional anesthesia is published.[13] It is important to have awareness of these issues; however, the collection of quality data is an important prerequisite for research, and for arriving at appropriate country-centric strategies for perioperative pain management.