Prolonged use of opioids after surgeryBMJ 2014; 348 doi: http://dx.doi.org/10.1136/bmj.g1280 (Published 11 February 2014) Cite this as: BMJ 2014;348:g1280
- Christian Dualé, anaesthetist
- 1CHU Clermont-Ferrand, Centre de Pharmacologie Clinique; Inserm, CIC 50, U1107 “Neuro-Dol”, F-63003 Clermont-Ferrand, France
In a linked paper (doi:10.1136/bmj.g1251), Clarke and colleagues present the results of a large retrospective cohort study conducted in Canada in 39 140 patients aged 66 or more who underwent major elective surgery and had never taken opioids before the procedure.1 Nearly half of the patients were discharged from hospital with an opioid prescription, illustrating that anaesthetists and surgeons no longer hesitate to use major analgesics beyond the immediate postoperative period. Although this trend has a positive effect on patient comfort and rehabilitation, concern has been raised by another important result from this study—that 3.1% of the patients were still taking opioids more than 90 days after surgery. Similarly, a 7.7% rate of opioid prescription has been reported at one year after low risk day surgery,2 and a follow-up study recently showed that 15% of women started or increased their purchase of analgesics after hysterectomy for benign disease.3 The medical profession therefore needs to ask whether long term opioid use is a real problem, and, if so, how it could be avoided.
Some may argue that 3.1% is quite a low rate of prolonged use for patients who have undergone major, invasive surgery, and that this figure may simply represent an appropriate response to patients’ need for pain relief. However, use of opioids several months after surgery is not in accordance with the expected time course of postoperative healing. Also, as the authors’ discuss, once these figures are extrapolated to the whole population, a large number of people may be affected. Although there is no direct evidence from the current study, we can assume that some of these patients are at risk of inappropriate long term use of opioids. This situation should be considered in the broader context of an increase in prescriptions for opioid drugs in Western countries. First observed in the United States in the early 2000s, and now identified in statistics on European populations, this trend results from a change in attitudes about the management of pain.4 5 Long term opioid use is, however, becoming a public health problem, with growing reports of tolerance, addiction, cognitive effects, misuse, and acute toxicity. Also, clinical manifestations of opioid induced hyperalgesia (hypersensitivity to pain), although masked by the intake of opioids, may be revealed at times of the day when blood levels are low. This effect may have direct and adverse consequences for the health of long term opioid users, increasing their risk of pain disorders and mental health problems.6
It is currently thought that surgery can induce central sensitisation of the nociceptive pathways, leading to a predisposition to pain disorders.7 The high doses of opioids given intraoperatively by anaesthetists are also suspected of inducing long term hyperalgesia and tolerance.6 However, although these processes are well documented in preclinical and some clinical pilot studies, they may not fully explain the need for analgesics months after surgery. In addition, evidence is growing that some types of surgery are harmful to nerve endings and may induce neuropathic pain, a fact illustrated by a recent meta-analysis of observational studies8 and a prospective survey from France.9 Interestingly, the current study found that thoracic procedures were a risk factor for long term opioid use,1 as three conditioning processes are combined in these patients: central sensitisation (from major surgery), opioid induced hyperalgesia (from high doses of intraoperative opioids), and neuropathic pain (from damage to intercostal nerves).
The prolonged use of opioids by certain patients after surgery can, however, be avoided. Firstly, anaesthetists should be encouraged to use analgesic strategies that help prevent central sensitisation and reduce doses of perioperative opioids, such as nerve blocks or drugs acting at the spinal level, such as ketamine.7 Secondly, opioids are a second line recommended option to manage peripheral neuropathic pain, the first line option being antidepressants or gabapentinoids.10 To avoid inappropriate use of drugs, doctors should look for signs of neuropathic pain in any patient still reporting pain three months after surgery. Screening tools have been developed for this purpose11 as well as precise guidelines to confirm the diagnosis.12 Finally, opportunities must be created to taper or withdraw opioids as soon as possible after surgery. A detailed conversation with patients about the benefits and risks of prolonged treatment would be a good place to start. Patients with a low socioeconomic status seem to be particularly vulnerable to prolonged use of opioid agents,1 3 and education about treatment could be particularly important for this group.
More research must be done to explore the time course of postoperative pain, including any neuropathic features. Better and longer follow-up studies of patients having major surgery are also needed. Both surgeons and anaesthetists need to collaborate better with general practitioners, who manage the postoperative period. The months after major surgery are a tricky time during which medical problems are not always resolved, but it should be possible to reduce the incidence of prolonged use of opioids if optimal care pathways are developed, including a smooth transition from secondary to primary care.
Cite this as: BMJ 2014;348:g1280
Competing interests: I have read and understood the BMJ Group policy on declaration of interests and declare the following interests: None.
Provenance and peer review: Commissioned; not externally peer reviewed.