Re: Prolonged use of opioids after surgery
We read with great interest the recent editorial and article regarding prolonged opioid use after surgery. We certainly agree that inappropriate administration of opioids is harmful and much education is required to limit the culture of such prescribing. Bold inferences were made on the front cover,‘ time to stop the handouts’ and within the editorial pictures, opioids were likened to ‘smarties’. Based on a figure of 3.1% of long term opioid use this may be sensationalising an entirely appropriate level of use.
There is now an increasing awareness of chronic post surgical pain (CPSP), its risk factors and prevention strategies. Multimodal analgesia may be opioid sparing immediately postoperatively but there is no conclusive evidence that strategies such as ketamine(1) and regional anaesthesia(2) are effective for long term CPSP.
There is a mention of intra operative use of opioids leading to hyperalgesia and tolerance. However the evidence for this is mixed and sparse,(3) being mainly described in those on long term opioids. Considering their overwhelming benefits in the perioperative setting, few would restrict its current use.
What is even less well documented is the correct treatment of CPSP once it occurs. There is wide epidemiological variation but approximately 10-30% will have some chronic pain after surgery(4) with even higher rates post thoracotomy. The question then arises do opioids have a place in the treatment of this phenomenon? If they do then 3.1% does then not seem like such a high figure. The editorial points out that the pain in CPSP has a large neuropathic component and thus it makes sense to treat with anti neuropathic agents. However opioids too can be effective in neuropathic pain(5) and in our clinical experience a combination strategy is often required. Additionally, CPSP may not always be entirely neuropathic. In one particular study following thoracotomies, a procedure with a high incidence of nerve injury only half had significant neuropathic symptoms.(6)
In the Clarke et al study the population was over 65. In this demographic we need to consider what are our alternatives. Non steroidals may not be the best option even in the short term perioperative period. Side effects from all drugs including opioids and anti neuropathic agents may be intolerable. In many instances opioids may be our ‘best fit’.
When considering the harmful effects of chronic opioid prescription clearly there is a difference between a weak opioid, a strong opioid and their dosages. This is not differentiated in the 3.1% figure. This is important as it will contribute to the extent of any adverse effects.
In conclusion we all agree that the inappropriate prescription of opioids is a problem that needs attention but there is still much we don't know about prescribing for CPSP. In reality a prescription rate of 3.1% in the long term may not be as alarming as we think.
1)Sen H, Sizlan A, Yanarates O, et al. A comparison of gabapentin and ketamine in acute and chronic pain after hysterectomy. Anesth Analg. 2009;109:1645-1650
2) Andreae MH, Andreae DA. Regional anaesthesia to prevent chronic pain after surgery: a Cochrane systematic review and meta-analysis. Br J Anaesth. 2013 Nov; 111(5):711-20
3)Chu LF, Angst MS, Clark D. Opioid-induced hyperalgesia in humans: molecular mechanisms and clinical considerations. Clin J Pain 2008; 24:479-96.
4)Bruce J, and Quinlan J. Chronic post surgical pain. Reviews in Pain 2011; 5 (3): 23-9
5)Rowbotham MC, Twilling L, Davies PS, Reisner L, Taylor K, Mohr D. Oral opioid therapy for
chronic peripheral and central neuropathic pain. N Engl J Med 2003; 348:1223-32.
6)Steegers MAH, Snik DM, Verhagen AF, van der Drift MA, Wilder-Smith OHG. Only half of the chronic pain after thoracic surgery shows a neuropathic component. J Pain 2008; 9: 955–61
Competing interests: No competing interests