A study from the United States has found that patients prescribed tramadol for postoperative pain have a higher risk of prolonged opioid use relative to those given other short-acting opioids.

The authors undertook a retrospective observational study of opioid-naïve patients undergoing elective surgery between 2009 and 2018 using insurance claims data from a large private US health plan.

Overall 444,764 patients fulfilled the inclusion criteria of having at least 180 days of follow-up information.

Of these, 357,884 filled a discharge prescription for one or more opioids following one of the 20 elective surgical operations identified in the study. These included a range of general surgical (for example, hernia repair and laparoscopic cholecystectomy), orthopaedic (including total knee replacement and carpal tunnel release), and colorectal, urological and thoracic procedures, in order to cover multiple specialties and a range of expected postoperative pain levels.

For analysis three commonly used definitions of prolonged opioid use were used:

• Additional opioid use post surgery (at least one opioid prescription filled 90-180 days after surgery)

• Persistent opioid use after surgery (any span of opioid use starting in the 180 days after surgery and lasting at least 90 days)

• The CONSORT definition of long-term opioid use (opioid use episode starting in the 180 days after surgery that spans at least 90 days and includes either ten or more opioid fills or 120 or more days’ supply of opioids).

The most commonly prescribed opioid post-surgery was hydrocodone (53.0% of those prescribed a single opioid), followed by short-acting oxycodone (37.5%). Tramadol was relatively infrequently prescribed (4.0%).

The unadjusted risk of additional opioid use after surgery was 7.10% (n = 31,431); the figure for persistent opioid use was 1.0% (n = 4,457); and 0.5% of patients (n = 2,027) met the CONSORT definition of long-term opioid use.

Use of tramadol post surgery was associated with increased adjusted risk of all three definitions of prolonged opioid use, see table 1, below. Tramadol prescribing as a single opioid was associated with a 6% increase in the adjusted risk of additional opioid use relative to people receiving other short-acting opioids,

a 47% increase in the adjusted risk of persistent opioid use and a 41% increase in the adjusted risk of CONSORT-defined long-term opioid use.

The study authors conclude:

‘We found that tramadol, a drug that is scheduled at a lower risk level than other common short-acting opioids has a similar or somewhat greater risk of prolonged opioid use after surgery.

They call for a rescheduling of tramadol ‘to a level that better reflects its risk of prolonged use’.

In an accompanying editorial, a UK consultant in complex pain comments: ‘Prescribing of any opioid should be in accordance with the evidence and with the effects and side effects reported by individual patients, as well as with the patient’s and prescriber’s full knowledge of the likelihood and risks of long-term use.’¹

Opioid medications continue to have an important role in the management of severe acute pain. Ongoing prescribing following an acute painful event needs to be managed with care, and the potential for tramadol to be associated with longer-term use must not be underestimated.

Dr Jez Thompson