Opioid Prescribing Limits for Acute Pain

Opioid Prescribing Limits for Acute Pain

The opioid epidemic has claimed hundreds of thousands of lives in the U.S. over the past decade.¹ Opioids are commonly prescribed for acute pain, but the amount in prescriptions often greatly exceeds what patients need.² Leftover opioids can be diverted or misused, adding fuel to the epidemic.

Definition: acute pain is the sudden onset of pain that lasts no longer than 90 days, such as pain after surgery.

To reduce leftover opioids, at least 35 states have implemented limits that restrict either the duration or number of doses in opioid prescriptions for acute pain (as of October 2019). Limits have also been implemented by many health insurers, at least one major pharmacy chain, and the three largest pharmacy benefit managers in the country, which collectively manage drug benefits for 180 million Americans.³ Consequently, almost every opioid prescription for acute pain in the U.S. is now subject to at least one limit. 

Unfortunately, early evidence suggests that the effects of limits on opioid prescribing have been modest at best.^4-8 For example, one study found that implementation of 26 state limits was associated with just a 7% decrease in the duration of opioid prescriptions for patients new to opioid therapy.⁷

To identify potential explanations for these modest effects, a University of Michigan research team assessed variation in the design of state opioid prescribing limits.

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Variation in the design of state opioid prescribing limits

Thirty states with comprehensive state limits (i.e., not limited to opioid prescriptions from specific settings, such as emergency departments) were included in the analysis. The analysis was completed in October 2019.

The team found that limits vary along many dimensions: 

• Duration: Most limits restrict prescriptions to a 7-day supply, but some allow for a 14-day supply while others allow for a 3-day supply (Figure 1). Eight states also have a limit of daily or total dosage.
• Prescriptions Affected: Some limits affect prescriptions for “acute pain”, while others affect “initial prescriptions” for opioid-naïve patients. Some limits only affect prescriptions for opioids with high potential for misuse (e.g., “Schedule II” opioids) (Figure 2).
• Exceptions: Some state limits have no exclusions, while others have many. Common exclusions include: end-of-life care (25 states), cancer (25 states), chronic pain (17 states), and substance use disorder treatment (15 states). Some states have exceptions for a clinician’s “professional judgement” (12 states).

What might account for the modest effects of limits on opioid prescribing? 

Limits are too high: For a limit to reduce prescribing, it must restrict prescribing to a level that is lower than what the clinician would have otherwise written.

• In a national study of privately insured patients, the average duration of initial opioid prescriptions at the end of 2017 was approximately a five-day supply.⁹ However, most state limits set a seven-day supply restriction (Figure 1), meaning that most opioid prescriptions are not affected.

Limits are imprecisely designed: Most limits restrict the duration (days supplied) of prescriptions, but few concurrently restrict daily dosage.¹⁰ This may allow clinicians to still prescribe the same amount they would have previously.

• For example, under a new seven-day supply limit with no daily dosage restriction, clinicians who normally prescribe 84 pills over a 14-day period by writing for one pill every four hours could instead prescribe 84 pills over a seven-day period by writing for two pills every four hours.

Limits are sometimes voluntary: Allowing exceptions for professional judgment preserves clinician autonomy but may make limits more like guidelines than mandates.

Clinicians may not comply:

• Clinicians may not understand whether a limit should be applied due to lack of clarity.
  • For example, state limits that restrict initial opioid prescriptions often do not define how long a patient must have been opioid-free for the prescription to be considered “initial”.
• Clinicians may not understand which rules to follow when there are conflicts between the limits of states, insurers, pharmacy benefit managers, and pharmacies.
• Clinicians may choose not to comply with limits if enforcement is inconsistent or when patients have extenuating circumstances.
• Clinicians may engage in “gaming” behavior.
  • To provide patients with a larger opioid supply than allowed, they could write multiple short-duration prescriptions. For example, to provide a 14-day supply under a seven-day supply limit, the clinician could provide two paper prescriptions, each with a seven-day supply, writing in a future date for the second prescription.¹¹

Could making limits more restrictive make them more effective?

If every patient needed only a three-day supply of opioids, a uniform three-day supply limit could eliminate all excessive prescribing without worsening patient pain control. 

However, pain needs vary widely within conditions and between conditions,^12-13 making it impossible for any limit to achieve this ideal.

A highly restrictive limit will reduce prescribing to a greater degree than a less restrictive limit, but will also increase the number of patients who experience worsened pain control.