Opioid Analgesics: The Impact of the Initial Prescription

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A number of states including New York, New Jersey, and Massachusetts have recently enacted laws limiting the amount of opioid analgesics that can be designated on an initial prescription. Significant debate over these laws has focused primarily on whether they are unfair intrusions into the practice of medicine and, while they may be good for the overall public health, whether they actually are beneficial for the individuals for whom the drugs are being prescribed.

The first question no doubt will remain the subject of debate but we now have two new studies that provide a possible answer to the second one.

The first study used a 10% sampling of a national database of patients enrolled in a large number of managed care plans from 2006 to 2015; the objective was to examine whether the number of days for an initial opioid analgesic prescription and the dosage of that prescription had an impact on the duration of opioid use.¹

Patients who had a diagnosis of cancer or substance use disorder within the 6 months preceding their first opioid prescription were excluded as were those whose first prescription was for buprenorphine for the purpose of treating opioid abuse or addiction. Eligible patients were followed until the end of the study or until there had been a lapse of 6 months or longer since an opioid prescription had been filled.

Approximately 1.3 million patients met the inclusion criteria and of these slightly more than 33,500 (2.6%) continued opioid therapy for more than one year.

Results: older, female, pain dx

Those who continued using opioids were more likely to be older, female, have a pain diagnosis prior to initiation of treatment with opioids, to be enrolled in a public health insurance program (Medicare or Medicaid) or be self-insured, and to be started on higher doses of opioids than those who used opioids for less than one year. The authors did not speculate on why these factors might affect the length of opioid use and apart from possibly the higher dose, there is nothing inherent in them that would indicate why they do.

The probability of continued opioid use for more than one year increased with each additional day of use after the third day and there were marked increases in use when the initial opioid prescription lasted for more than 10 days with a another marked increase when it was written for more than 30 days.

Increased risk of extended use was also associated with receiving a third prescription for the drug or when the initial cumulative dose was for 700 or more milligrams per day of morphine or an equivalent dose of another opioid.

There was also an increased likelihood of extended use when the initial prescription was for a long-acting opioid, tramadol, or a short-acting opioid other than hydrocodone or oxycodone.

Next: Yes, tramadol is an opioid

Image ©Steve Heap/Shutterstock.com

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Study authors noted that they found the inclusion of tramadol in this list unexpected and suggested several reasons for it including the conjecture that it is being prescribed more often for chronic pain. I believe they may have overlooked another more likely explanation.

Based on my own experience, many physicians are still not aware that tramadol is an opioid. I have been at lectures on analgesic drugs where tramadol is not included in the discussion of opioids. Tramadol works via two mechanisms, combining weak mu-opioid receptor agonism with serotonin-norepinephrine reuptake inhibition. While the weak opioid component may reduce the abuse potential of tramadol relative to opioids like oxycodone and hydrocodone, it can still be misused and addiction can occur.

It is my belief that many physicians may prescribe tramadol under the false belief that it is either not an opioid or that it has virtually no abuse potential.  

Being one of the first studies of its nature the results need to be replicated before any generalizations can be made. Other limitations include no documentation of intensity of the pain for which patients were being treated and no measurement of benefits from treatment. Also treatment indications were only classified into the very general categories of back, neck, head, and joint pain.

The authors also noted that it is difficult to determine whether the extended use of opioids was a conscious decision to treat chronic pain or if, in at least some cases, it was an unintentional outgrowth of treating acute pain.

Its methodology and results should make every physician who prescribes opioids give careful thought to the length of an initial prescription as well as the dose as both may have a marked impact on a patient’s future use.

Next: When first Rx is in the ED

Image of tramadol molecule ©Raimundo70/Shutterstock.com

When first Rx is in the ED

The second study also utilized sampling from a national data base of patients, these enrolled in Medicare Part D, and examined whether the opioid prescribing patterns of emergency department physicians had any correlation with how long patients ended up using opioids.²

The physicians studied were classified into groups-“high-intensity” and “low-intensity” prescribers-based on the number of opioid prescriptions per patient treated. Both groups included physicians in the same hospitals who saw the same patient populations. Eligible patients had not received an opioid prescription within 6 months of the index ED visit. The primary outcome measure was use of opioids for 180 or more days following the initial prescription which was considered long-term use. It also examined whether there was any relationship between the prescribing habits of the physicians and rates of subsequent hospital encounters.

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Patients who were treated by high-intensity prescribers were significantly more likely to be using opioids a year later than those who were treated by low-intensity prescribers. The first group also had a significantly higher number of subsequent hospital encounters for falls or fractures during that year.

The authors speculate that one possible explanation for their findings is the phenomenon known as “clinical inertia” where once patients are started on a medication, physicians may be less likely to question the need for it and continue to prescribe it.

As the authors note, the two major limitations of the study are that it was only observational so didn't seek to establish causality and was limited to the population eligible for Medicare Part D-typically aged 65 years and older.

Despite their limitations, both studies highlight how what may appear to be relatively benign and unimportant decisions may end up having long-term consequences of great importance for our patients.

Image ©Steve Heap/Shutterstock.com

References:

1. Shah A, Hayes CJ, Martin BC. Characteristics of initial prescription episodes and likelihood of long-term opioid use - United States, 2006-2015.Morb Mortal Wkly Rep.2017;66:265-269.

2. Barnett ML, Olenski AR, Jena AB. Opioid-prescribing patterns of emergency physicians and risk of long-term use. N Engl J Med. 2017;376:663-673.