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Part II of a California Workers’ Compensation Institute research series on low-volume/high-cost drugs used to treat California injured workers identifies three Dermatological drugs, three Opioids, and three Antidepressants that represent a relatively small share of the prescriptions within their therapeutic drug group, but due to high average reimbursements, have become cost drivers, consuming a disproportionate share of the payments.

The report reveals that Dermatologicals were the fourth most prevalent drug category in 2021, with 9.3% of the workers’ comp prescriptions, but ranked second (behind Anti-Inflammatories) in total drug spend, consuming 17.3% of all prescription drug payments. That was up from 12.8% in 2012, which the study ascribes to increased utilization and the emergence of high-priced topical analgesics. Diclofenac sodium topicals jumped from 0.5% of all workers’ comp prescriptions in 2012 to 5.4% in 2021 – fourth among all drugs dispensed that year, and they represented 58.1% of the 2021 Dermatological prescriptions, but with inexpensive generics widely available, their average reimbursement was a relatively low $65, so they consumed only 23.5% of the Dermatological dollars. In contrast, the study notes three other low-volume/high-priced drugs that have become Dermatological cost drivers:

– – Diclofenac sodium and adhesive sheets (dispensed as Xrylix kits, in 2021 these kits accounted for just 0.3% of the Dermatological prescriptions, but with an average payment of $4,126, they consumed 7.2% of the dermatological drug spend).
– – Lidocaine/menthol (this drug was dispensed in various forms, but NuLido gel and Terocin patches were key cost drivers. Lidocaine/menthol represented only 1% of the Dermatologicals dispensed in 2021, but at an average of $1,050 per prescription, it accounted for 6.2% of the Dermatological payments.
– – Diclofenac epolamine (dispensed as Flector patches at an average of $570 per prescription, or as generic equivalents at an average of $577, diclofenac epolamine comprised just 1.7% of the 2021 Dermatological prescriptions, but 5.9% of the payments within the group).

Opioid use in workers’ comp has been falling for more than a decade and with the adoption of Opioid and Pain Management Treatment Guidelines in late 2017 and a Formulary in 2018, Opioids’ share of the prescriptions continued to drop, falling to 9.4% in 2021 (down from 29.4% in 2012), while their share of the total drug spend fell to 5.8% (down from 26.7% a decade earlier). At the same time, the mix of Opioids used to treat injured workers shifted. The study noted three low-volume/high-priced Opioids that have become cost drivers within their group:

– – Buprenorphine, typically used to treat Opioid Use Disorder for patients in Medication-Assisted Treatment plans, in 2021, it accounted for 5.2% of the workers’ comp Opioids, and with an average payment of $363, it consumed 35.4% of the total Opioid reimbursements – more than any other Opioid.
– – Tapentadol HCl, used when other pain medications do not work well or cannot be tolerated, but only available as a brand drug (Nucynta or Nucynta Extended Release) it represented just 0.6% of the Opioid prescriptions, but at $590 per prescription, it accounted for 6.4% of the total Opioid drug spend.
– – Oxycodone, prescribed for moderate to severe pain, is available in a variety of generic and brand formulations, including extended-release and abuse-deterrent varieties. In 2021, 5.9% of Opioid prescriptions were for oxycodone, and at $145 per prescription, it consumed 16.0% of all Opioid payments.

The top four Antidepressants dispensed to injured workers in 2021 represented nearly 2/3 of the Antidepressants used, but all four were relatively low-cost drugs, so they accounted for only 42.5% of the payments in this drug group. In contrast, the study identified three low-volume/high-priced drugs that consumed a disproportionate share of the Antidepressant drug spend:

– – Vortioxetine HBr, used to treat Major Depressive Disorder, remains under patent and is only available as brand-name Trintellex. Available in 5, 10, and 20 mg tablets, this drug carries a black box warning noting an increased risk of suicidal thoughts and behaviors. In 2021, only 1.0% of the Antidepressant prescriptions in California workers’ compensation were for Vortioxetine HBr, but with an average reimbursement of $476, this drug comprised 12.4% of all Antidepressant payments.
– – Desvenlafaxine, an extended-release tablet that comes in various strengths, is used to treat major depression. It is available as a brand drug (Khedezla, Pristiq), with average payments as high as $642 per prescription, but since the introduction of generic versions in 2017, brand versions have declined to 14 to 15% of the prescriptions. Payments for generic desvenlafaxine averaged $58 to $66 from 2019 to 2021, which helped drive down the average reimbursement for this drug. In 2021, desvenlafaxine represented 1.0% of workers’ comp Antidepressants, but the average payment was still $131, so it accounted for 3.5% of the Antidepressant payments.
– – Bupropion HCl is used to treat depression, anxiety, and other mood disorders, and to aid smoking cessation. Available as a brand drug (Wellbutrin, including an extended-release version that tends to be very expensive), or in generic versions, which accounted for 98% of the Bupropion HCl dispensed to injured workers in 2021. Unlike generics, where the average payment declined from $121 in 2012 to $25 in 2021, over that same decade average reimbursements for brand versions of bupropion HCl increased nearly 10-fold from $267 to $2,614. The dominance of generic buproprion HCl has helped contain the total payments for this drug, but the 2% of the prescriptions dispensed as high-cost brand drugs drove the average payment up to $77 in 2021 — more than three times the $25 average paid for generics. As a result, bupropion HCl, which accounted for 7.6% of the Antidepressant prescriptions in 2021, consumed 16.3% of the Antidepressant payments.

CWCI has published more details and analyses on these drugs in a Spotlight Report, Cost-Driver Medications in the Top California Workers’ Comp Therapeutic Drug Groups: Part II, Dermatologicals, Opioids, and Antidepressants. Institute members and subscribers can log on to and access the report under the Research tab, others can purchase a copy from the CWCI’s online store. Part III of CWCI’s research on low-volume/high-cost medications will focus on medications found in the Musculoskeletal and Ulcer drug categories.