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Part I of a new California Workers’ Compensation Institute (CWCI) research series on low-volume/high-cost drugs used to treat injured workers in California spotlights a handful of Anti-Inflammatory and Anticonvulsant medications that account for a relatively small share of the prescriptions within their therapeutic drug groups, but that have become significant cost drivers by consuming a disproportionately large share of the payments.

CWCI’s analysis of Anti-Inflammatory and Anticonvulsant drugs used in California workers’ compensation is the first of a three-part series that uses data from the Institute’s Prescription Drug Application to track changes in the distribution of California workers’ compensation prescriptions and prescription payments over the past decade, and to identify medications with high average reimbursements that have an outsized impact on the total payments within their drug group.

The authors of the study note the changes in the average amounts paid per prescription for each of the highlighted drugs over the 10-year study period (service years 2012 through 2021), as well as changes in the percent of the prescriptions dispensed as a brand rather than a generic drug, and review factors that contribute to the high cost of the medications.

Among the key findings for the Anti-Inflammatory and Anticonvulsant drugs:

– – Ibuprofen and naproxen represented 2/3 of the Anti-Inflammatories dispensed in 2021, but with average payments of $12 and $49 respectively, they were relatively cheap, so it was low-volume, high-cost fenoprofen calcium (with an average payment of $1,479), and ketoprofen (with an average payment of $1,073) that kept Anti-Inflammatories at the top of the list in terms of total drug spend.
– – Fenoprofen calcium represented 1.4% of the 2021 Anti-Inflammatory prescriptions but 33.2% of the payments, while ketoprofen represented 0.6% of the prescriptions but 9.8% of the payments.
– – Fenoprofen calcium represented just 0.5% of all workers’ compensation prescriptions in 2021, but 8.1% of the total drug spend within the system, by far the largest percentage of any single drug.
– – The biologic etanercept (Enbrel) accounted for less than 0.1% of the Anti-Inflammatory prescriptions in 2021 but was only available as a brand drug with an average payment of $7,716, so it consumed 4.3% of the Anti-Inflammatory payments. On the other hand, none of the fenoprofen calcium or ketoprofen dispensed in 2021 was brand, which shows that generics are not always inexpensive.
– – Fenoprofen calcium, ketoprofen, and etanercept are not in the national Medicaid database, so they have no Federal Upper Limit (FUL) – the maximum fee allowed under Medicaid, which also serves as a price control in the Medi-Cal and California workers’ compensation pharmacy fee schedules. Instead, these drugs are paid at 83% of their average wholesale price, which is based on manufacturer pricing.
– – Four Anticonvulsant drugs (lacosamide, levetiracetam, lamotrigine, and pregabalin) accounted for 24.2% of the 2021 Anticonvulsant prescriptions, but 72.5% of the Anticonvulsant drug spend.
– – Pregabalin, which is subject to prospective utilization review (UR) under the California Workers’ Compensation Formulary, was the second most common Anticonvulsant prescribed in 2021, but its 20.7% share of the Anticonvulsant prescriptions was far below its 55.5% share of the payments.
– – Pregabalin’s share of the Anticonvulsant prescriptions increased after the Formulary and the Pain Management and Opioid Treatment Guidelines took effect in 2018, but the average payment peaked at $557 that year, and in 2019 so too did pregabalin’s share of the Anticonvulsant drug spend (77.5%) as the FDA approved nine generic versions of the drug, which quickly hit the market at a fraction of the cost of the brand version.
– – By 2021, the payment differential between brand and generic pregabalin had widened, as the average payment for generics fell to $152 per prescription while the average payment for brand versions rose to $714. By that point, however, generics accounted for 92% of the pregabalin prescriptions, so the overall average payment for pregabalin declined to $197 in 2021.
– – The 3 other Anticonvulsants highlighted in the study accounted for much smaller shares of the prescriptions within their drug group in 2021 (0.7%, 1.7%, and 1.0% respectively), but their high average payments made them significant cost drivers.
– – Lacosamide, which is Not Listed in the formulary but can be used if the prescriber presents an evidenced-based rationale for its use was only available as a brand drug at an average payment of $832. It accounted for just 0.7% of the Anticonvulsant prescriptions, but 8.3% of the payments.
– – Levetiracetam, which is subject to prospective UR, accounted for 1.7% of the 2021 Anticonvulsant prescriptions. Available as a brand and generic drug, in recent years levetiracetam has been increasingly dispensed as a brand drug (with an average reimbursement of $1,880 in 2021), which drove the overall average payment per prescription up to $274, so it consumed 6.3% of the Anticonvulsant dollars.
– – Lamotrigine, which is also subject to prospective UR, accounted for 1.1% of the Anticonvulsant prescriptions in 2021. While 95% of the 2021 prescriptions were generics, with an average payment of $62, the average amounts paid for various brand versions, including an extended-release version, were much higher, which pushed the overall average payment for Lamotrigine up to $174 per prescription, so it accounted for 2.4% of the Anticonvulsant drug spend.

CWCI has published the first part of its study in a Spotlight Report, Cost-Driver Medications in the Top California Workers’ Comp Drug Groups: Part 1, Anti-Inflammatories & Anticonvulsants. Institute members and subscribers can log on to the Institute’s website at to access the report under in the Research section, others can purchase a copy from the Institute’s online store.

CWCI research on low-volume/high-cost medications will continue with Part II in the series, which will focus on medications found in the Dermatological, Opioid, and Antidepressant drug categories, while Part III will highlight low-volume/high-cost Musculoskeletal and Ulcer Drugs.