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CWCI: Dermatologicals Are Now the Costliest Drug Group in California Workers Comp

Oakland, CA – New data from the California Workers’ Compensation Institute (CWCI) shows recent shifts in the types  of drugs prescribed to injured workers in California, and in the distribution of payments for those medications, with anti-inflammatory drugs ranking first in terms of the number of prescriptions, but dermatologicals, which include a number of high-priced, private label drugs, accounting for the biggest share of the total drug spend. 

The latest data from CWCI’s Prescription Drug Interactive Application ranks the top 10 therapeutic drug groups in California workers’ comp based on the volume of prescriptions and total reimbursements. Comparing the distributions of drugs dispensed to injured workers from 2016 through June 2024, CWCI analysts noted the shifts in prescription drug utilization and reimbursement among the drug groups suggested an association between the ongoing decline in opioid use with the state’s adoption of the Opioid and Pain Management Guidelines into the Medical Treatment Utilization Schedule (MTUS) in late 2017, and the implementation of the MTUS Formulary in 2018. The historical data show that anti-inflammatories such as ibuprofen and naproxen, often used as non-narcotic alternatives to treat pain, surpassed opioids to become the top drug group in 2016, and by 2021 they accounted for a record 35.3% of all prescriptions dispensed to California injured workers. Looking at the mix of prescriptions by drug ingredient shows that most of the growth in anti-inflammatories was due to increased use of inexpensive ibuprofen, which increased from 32.9% of all anti-inflammatories in 2017 to 42.2% in 2021, at which point it stabilized. Ibuprofen remains the most heavily used drug in California workers’ compensation, representing 14.1% of all prescriptions in 2023 and 13.7% in the first half of 2024, ranking well ahead of naproxen, which ranks second with 8.2% of the 2023 prescriptions and 7.9% of the prescriptions from the first half of 2024. At the same time, opioids’ share of the workers’ comp prescriptions fell to 7.9% in 2023 and 7.6% in the first six months of last year, about a third of its 22% share in 2016 and about a quarter of its record 30.8% share in 2010.

Dermatological drugs are often used to treat pain, and with opioid use declining their share of the workers’ comp prescriptions grew from 4.9% in 2016 to 12.6% in the first half of 2024. Though many different dermatologicals are used to treat injured workers, the breakdown by drug ingredients shows most of that growth was due to the increased use of prescriptions containing lidocaine and/or diclofenac sodium, which together increased from 46% of the dermatological prescriptions in 2016 to 81.6% in the first half of 2024. Like opioids, musculoskeletal drugs have seen their share of the prescriptions drop sharply over the past 8-1/2 years, falling from 10.7% of the prescriptions in 2016 (third behind anti-inflammatories and opioids) to 5.8% in 2021 before they leveled off at just over 6% over the past 2-1/2 years (sixth among all drug groups). This decline coincided with the implementation of the Formulary in January 2018, as under the Formulary, musculoskeletal drugs are not exempt from utilization review except for limited special fill or perioperative use where only limited quantities can be dispensed.

In 2022, anticonvulsants, which are often used to treat neuropathic pain, surpassed opioids to become the third most prescribed workers’ comp drug group and since then they have maintained that ranking, while antidepressants surpassed opioids in 2023 (accounting for 8.0% of the prescriptions) and they remained the fourth most prescribed drug group in        the first half of 2024 (8.1%). Ulcer drugs, typically used to treat digestive issues associated with opioids and anti-inflammatories are the only other drug group that has comprised close to 5% of the prescriptions since 2020, though their share fell to a 10-year low of 4.7% in the last year and a half, reflecting the continued downtrend in opioid use. 

The CWCI app’s ranking of the top drug groups based on total payments shows that the top 10 groups combined for 78.3% of the total drug spend in the first half of 2024, nearly matching the 78.8% share from 2016, but the distribution of  prescription dollars among the drug groups shifted, as opioids fell from 18.2% of the payments in 2016 (when they were still the costliest drug group) to 4.9% in the first half of 2024 (when they ranked fifth). Anti-inflammatories’ share of the drug spend fell from 16.9% in 2016 to 13.1% in 2018, but after the state added the Opioid and Pain Management Guidelines into the MTUS and implemented the Formulary, utilization and total payments for anti-inflammatories spiked as they were heavily relied upon to treat pain during the pandemic, so they became the most costly drug group, consuming 24.0% of the prescription dollars in 2020, 25.1% in 2021, and 20.2% in 2022. That surge, however, did not last, as the anti-inflammatories fell to 17.4% of the prescription dollars in 2023, while dermatological drugs consumed more than one out of five prescription dollars then continued to top the list in the first half of 2024, representing 18.9% of the drug spend. 

Anticonvulsants’ share of the pharmaceutical payments grew from 9.1% in 2016 to a peak of 14.5% in 2018, but after the approval of generic versions of the anticonvulsant pregabalin in 2019, their share of the payments fell to 7.7% in 2020, then leveled off at around 8% where it has held steady. Much more notable has been the growing proportion of the prescription dollars paying for migraine drugs. In the first half of 2024, migraine drugs only ranked 13^th among the drug groups in terms of prescription volume, yet they were the fourth costliest drug group due to the introduction of several high-cost, brand name migraine drugs that have become increasingly prevalent in workers’ compensation. As a result, over the past 6-1/2 years, the migraine drugs’ share of the California workers’ comp total drug spend has climbed from 0.5% in 2018 to 6.7% in the first half of 2024, far exceeding the growth in any other drug group. 

A review of total payments by drug ingredient shows that from January through June of last year, the dermatological lidocaine (average payment $159: $216 brand, $151 generic) ranked first among all drugs in terms of the California workers’ compensation total drug spend, accounting for 8.5% of all payments. That was more than twice the percentage noted for the anti-inflammatory naproxen, which ranked second with 4.2% of the prescription dollars, just ahead of the anticonvulsant pregabalin, which ranked third with 4.1%. The dermatological diclofenac sodium (topical) ranked fourth, consuming 3.1% of the pharmaceutical payments, while the anti-inflammatory meloxicam and the migraine drug rimegepant sulfate rounded out the top 6 drugs, each consuming 2.8% of the total drug spend in the first half of 2024.

CWCI has published additional details and complete lists of the top 10 California workers’ compensation therapeutic drug groups based on prescription volume and payments from 2016 through June of 2024 in Bulletin 2025-01, which is available to CWCI members and research subscribers under the Communications tab at www.cwci.org.