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New data from the California Workers’ Compensation Institute (CWCI) shows the types of drugs used to treat injured workers in California, and the distribution of payments for those medications, has shifted dramatically over the past decade, with opioids becoming far less prevalent and anti-inflammatory drugs (NSAIDs) accounting for an increasing share of the prescriptions and the total drug spend within the workers’ comp system.

The results show that NSAIDs, often used as non-narcotic alternatives to treat pain, surpassed opioids to become the top workers’ comp drug group in 2016, and in 2021 they increased to a record 34.0% of the prescriptions dispensed to injured workers in California.

The distribution of prescriptions by drug ingredient revealed that most of the growth in NSAIDs over the past decade has been due to the increased use of inexpensive ibuprofen, which increased from 27.0% of all anti-inflammatories in 2012 to 41.2% of the NSAIDs dispensed in 2021.

As a result, ibuprofen is now the most heavily used drug in workers’ compensation, accounting for 14.1% of all prescriptions dispensed last year, ranking well ahead of another NSAID, naproxen, which ranked second, accounting for 8.3% of the prescriptions dispensed to injured workers.

Meanwhile opioids’ share of the workers’ comp prescriptions continued to decline, falling to 10.2% last year, though most of the decline in opioid use within the past decade occurred between 2012 and 2019, as opioid’s share of the prescriptions has been relatively stable over the past 3 years, only edging down slightly from 11.7% to 10.2%.

As in 2020, anticonvulsants, dermatologicals, and antidepressants rounded out the top five most prescribed drug groups in 2021. Like NSAIDs, anticonvulsants and dermatologicals are often used to treat pain, and their share of the workers’ comp prescriptions has risen over the past decade, while antidepressants’ share, which ranged between 5.2% and 6.6% from 2012 through 2019, climbed to a record 8.0% in 2021 – the second year of the pandemic.

On the other hand, musculoskeletal drugs have fallen from 10.6% of all workers’ comp prescriptions in 2016 to 6.0% of the prescriptions last year, a drop that followed the state’s implementation of a workers’ comp formulary in 2017. The formulary made most prescriptions for musculoskeletal drugs subject to utilization review, with limited exceptions where they are allowed as special fill or perioperative drugs.

Ranking the top therapeutic drug groups based on total payments the CWCI analysts found that the top 10 groups combined for 77.9% of the total drug spend in 2021, down from 80.2% in 2012, when opioids consumed 26.2% of the prescription dollars (vs. 5.8% last year) and ulcer drugs accounted for 10.3% (vs. 6.3% in 2021).

With opioid payments down, NSAID’s share of the prescription dollars jumped from 13.4% in 2012 to 25.0% in 2021, dermatological drugs jumped from 12.9% to 17.2%, and anticonvulsants’ share rose from 4.9% to 8.6%.

The 2021 data also show that several other drug groups (psychotherapeutic and neurological drugs, anticoagulants, and antidiabetic drugs) that a decade ago each represented only 0.3% of the prescription dollars are now among the 10 most expensive drug groups, each accounting for between 2.6% and 2.9% of the total payments. Thus, combined payments for these drugs, which a decade ago represented only 0.9% of the prescription drug costs, accounted for 8.1% of the total drug spend in 2021.

Although ibuprofen and naproxen accounted for almost two-thirds of all NSAIDs dispensed last year, average payments for these drugs were $12 and $47 respectively, so they were relatively inexpensive.

However, the Institute found that as in 2020, two low-volume, high-priced NSAIDs, fenoprofen calcium and ketoprofen, made NSAIDs the most expensive drug category. In a March 2021 study, CWCI noted that under the formulary, both these drugs are exempt from prospective utilization review and because they are not listed in the national Medicaid database, neither has a Federal Upper Limit, which would serve as a price control in California workers’ comp. Instead, they are reimbursed at 85% of the average wholesale price, which is based on manufacturer pricing.