caring for patients who have chronic pain can be one of the most challenging issues in primary care. unlike almost any other primary care issue, the use of opioids for chronic pain tends to be the most likely one to pit a provider (or staff) against the patient, the antithesis of developing a strong primary care relationship. background:
–at our health center 20+ years ago, there were at most a handful of patients on opioids for chronic non-cancer pain. currently, most of us have at least a few patients on our schedule every day coming in for opioids for noncancer pain. Similarly, all of the patients addicted to opioids in the past were using illicit drugs (basically heroin and cocaine). now, my health center experience is that pretty much all of the young opioid-addicted patients are addicted to prescribed opioids (the very typical scenario of my young suboxone — ie buprenorphine/naloxone — patients is: they were given prescription opioids for acute pain, liked the feeling, increased their consumption by buying meds on the street, became addicted, had serious problems with life (maintaining job, relationships, etc), then came for suboxone and have mostly done very well).
–a recent study suggested more than 3% of adults receive long-term opioid therapy for chronic non-cancer pain!
–One of the major reasons for this dramatic transformation was within the medical profession: The Institute of Medicine came out with clear guidelines that pain was being underassessed and undertreated, raising the request that pain assessment be a vital sign, checked at every visit.
–However, parallel with this dramatic increase of providers’ prescribing opioids, there have been dramatic increases in deaths from opioid poisoning, for example hospitalizations for opioid related overdoses doubled in the 10 year period of 1995 to 2004 in Washington state. The MMWR (see Morbidity and Mortality weekly reports from the CDC Centers for Disease Control in the US MMWR Nov 1, 2011 Vital Signs: overdose of prescription opioid pain relievers –United States 1999-2008) reported that nearly 100 people/day died of drug overdoses in the United States in 2007 (that is >10x the death rate from asthma, at least as reported in the new york times today). The 2007 death rate was 3 times that of 1991. At this point the majority of overdose deaths are from prescribed opioid pain relievers. A study in Virginia found that the majority of overdoses resulted from drug diversion to others who then OD’d.
–Another recent study (see Ann Intern Med. 2010;152:85-92) looked at the patients themselves, finding that increasing doses of prescribed opioids was associated with increasing likelihood of overdose. This study was done at a large HMO in Seattle Washington with 10,000 people who received 3 or more opioid prescriptions within 90 days for chronic non-cancer pain between 1997 and 2005. They found:
–opioids were mostly prescribed for musculoskeletal pains, with two thirds specifically for back or extremity pain. Mean daily dose was 13.3 mg of morphine equivalents, with 80% of the patients using 1-20 mg per day and only 2% using 100 or more milligrams per day. (pretty low doses compared to what we typically see!)
–There were 51 opioid-related overdoses including 6 deaths
–converting the opioids to morphine equivalents using the CONSORT classification (see the article Clin J Pain 2008;24:521–527):
–overdose rates were somewhat higher in patients over 65 and in those with a history of depression or treatment of substance abuse
–Using the lowest group (1-20 mg per day) as a reference, those in the 20-50 mg per day had a 19% increase risk of serious overdose, the 50-100 mg per day had a 2 fold increased risk, in those greater than 100 mg per day had a 10 fold increased risk.
–similar numbers were found in a veterans study
Typically use of opioids is the last resort after the patient has failed pain management with non-opioid analgesics or anti-inflammatories, as well as other potential pain modulators (including tricyclic antidepressants; seizure meds such as gabapentin, pregabalin, or other anticonvulsants; muscle relaxants; NMDA receptor antagonist; and topical analgesics). although I suspect that we all have patients who have clearly responded to opioids clinically for non-cancer chronic pain, the actual data is not great:
–The average pain reduction through all of these modalities averages only about a 30% decrease in pain (which may well be important for the patient, but is important for us to realize and communicate to the patient that it is unlikely that they will get full resolution of their pain)
-for neuropathic pain, a 2013 Cochrane review of 31 trials (see DOI: 10.1002/14651858.CD006146.pub2) showed that: for acute pain of less than 24-hour duration (16 studies with 392 participants) — half had less pain with opioids than placebo, and more than a quarter had no difference. 6 studies with 170 participants found that the average pain score with opioids was 15/100 points less than with placebo. 14 studies with 845 participants were of intermediate duration lasting less than 12 weeks (which they comment were small studies, short duration, and potentially inadequate handling of dropouts creating bias of overestimating treatment effects) all demonstrated efficacy for neuropathic pain with at least 33% pain relief found in 57% of those on opioids versus 34% in those receiving placebo. no improvement in many aspects of emotional or physical functioning. Common adverse effects of constipation, drowsiness, nausea, dizziness, vomiting. They conclude that “the efficacy of opioids and chronic neuropathic pain is subject to considerable uncertainty”.
–for chronic nociceptive pain, the data are quite mixed for opioids. Again they are a last resort for therapy. A systematic review in the annals of internal medicine (Ann Intern Med 2007;146(2):116) of opioid treatment for chronic low back pain analyzed 4 studies comparing opioids with placebo or non-opioid controls found no difference in pain control. 5 studies directly comparing the efficacy of different opioids found a nonsignificant reduction in pain from baseline. However, the prevalence of lifetime substance use disorders ranged from 36-56%.
–one other very unfortunate trend is that chronic pain clinics used to be multi-disciplinary, involving social workers, psychologists or psychiatrists, neurologists or other pain specialists, anesthesia. now, these have devolved into just being anesthesiologists giving injections (at least in boston).
So, what does this mean in clinical practice when we see a patient in chronic pain who is not responding well to non-opioid therapies? My guess is that most of us see patients like this pretty often and find that often they do respond to opioids, though sometimes pretty high doses. However, the data suggest that this it is pretty uncommon in placebo-controlled trials (though were the trials constructed well?? with high enough doses of opioids??), and we know that there may be significant harms to the patient (esp if on large doses, as the studies above found) and to the community (with increasing availability of opioids on the street and associated overdoses, and we do see that in our community). Part of the answer is to follow people closely, have pain contracts/urine testing/etc, though this does tend to undercut the provider-patient relationship. What about the patient who comes into the practice on high doses of opioids? One of our residents just saw a person with trigeminal neuralgia on 60 mg of methadone and 180 mg of oxycodone a day (if you whip out your opioid conversion table, that is 450 morphine equivalents!!!). the patient states he is stable on this dose and needs to continue. His urine tox screens are appropriate. We ultimately decided to decrease his dosage in part because he may well be diverting meds (2 nieces who are reputed to be “drug addicts”) and we felt uncomfortable continuing with this high a dose for the patient’s own safety. But it’s hard to know what the right answer is…
geoff