Press Release


Bob Young

For Release:

July 13, 2023

CWCI Report Identifies Low-Volume/High-Cost Musculoskeletal and Ulcer Drugs

Oakland, CA – Part III of the California Workers’ Compensation Institute’s (CWCI) research series on low-volume/high-cost drugs used to treat California injured workers highlights three Musculoskeletal Drugs and three Ulcer Drugs that represent a small share of the prescriptions in their therapeutic drug groups, but due to high average payments, have become cost drivers, consuming a disproportionate share of the total drug spend for their groups.

The new report is the last of a three-part research series that uses data from the Institute’s Prescription Drug Application to track changes in the distribution of California workers’ compensation prescriptions and pharmacy payments over the past decade, and to identify medications that have a disproportionate impact on the total amount paid for drugs within their group.  The report notes changes in the average payment per prescription for the highlighted drugs over the 10-year study period (2012 through 2021), changes in the percent of the prescriptions dispensed as a brand rather than a generic drug, and factors that contribute to the high cost of the medications.    

According to the report, Musculoskeletal Drugs were the sixth most prevalent drug category in 2021, with 5.9% of the workers’ comp prescriptions, but because low-cost medications like cyclobenzaprine (Flexeril), tizanidine HCl (Zanaflex), and Baclofen (Gablofen, Lioresal) dominate the category, Musculoskeletal Drugs accounted for just 3.7% of the total drug spend.  At the same time, Ulcer Drugs, which were the seventh most common drug category, accounted for 5.4% of the prescriptions dispensed to injured workers in 2021, but 6.5% of the payments, even though nearly half of the prescriptions were for low-cost omezprazole (Prilosec).  Within each of these two drug groups the study identified three low-volume/high-cost drugs that have had an outsized impact on the total reimbursements for the group.  The Musculoskeletal medications highlighted in the report include:   

  • Viscosupplements are physician-administered preparations that usually come in pre-filled syringes containing hyaluronic acid (Hylan, Hyaluronan, and Sodium Hyaluronate). These preparations are injected into knees and other joints to lubricate and cushion the joint to reduce pain, stiffness, and swelling.  In 2021, viscosupplements accounted for 3.5% of the Musculoskeletal Drug prescriptions, but at an average payment of $688, they consumed 43.7% of the payments for this drug group.
  • Chlorzoxazone (Parafon Forte and Lorzone, both of which have been discontinued, but generic equivalents remain available) is a muscle relaxant used to treat acute pain from muscle spasms, saw its share of the Musculoskeletal Drug dollars increase as prescribers shifted from inexpensive 500 mg dosages to high-priced 250, 375, and 750 mg dosages. In 2021, Chlorzoxazone represented just 0.3% of Musculoskeletal prescriptions, but at $779 per prescription, it accounted for 4.9% of the Musculoskeletal Drug spend. 
  • Metaxalone (Skelaxin, Metaxall) is a muscle relaxant used for muscle spasms and acute pain from strains and sprains. Metaxalone’s share of the Musculoskeletal prescriptions doubled from 2.1% in 2019 to 4.2% in 2021, and the average payment rose from $95 to $160, causing its share of the drug payments within its group to more than triple from 4.0% to 12.3%.  A review of the dispensing data shows that most of the recent increase was driven by physician dispensing out of offices and clinics. 

The Ulcer Drugs highlighted in the report include:  

  • Lansoprazole (Prevacid) is a proton-pump inhibitor used to keep ulcers from developing in the stomach or intestines, or to treat acid reflux and heartburn in patients who take NSAIDs or opioids. From 2014 to 2021, Lansoprazole’s share of the Ulcer Drugs soared from 2.0% to 22.5% and its share of the payments in this drug group went from 2.3% to 44.4%, though the average payment per prescription only went from $180 to $204 during that span.  The shift toward Lansoprazole coincided with growing safety concerns and the eventual removal of much lower-price Ranitidine from the market.     
  • Esomeprazole magnesium (Nexium) is another proton-pump inhibitor that reduces acid in the stomach and is used to treat heartburn, acid reflux, and help prevent ulcers in patients taking NSAIDs and opioids, but it lasts longer than lansoprazole. Generics became available in 2016 and initially helped reduce the average payments, but from 2018 to 2021 the average reimbursement jumped 79.2 percent from $154 to $276.  As with lansoprazole, some of that increase was due to physician dispensing, though there is also a wide variation in the average amounts paid for generic versions of the drug.  With the recent increases in utilization and average reimbursement, esomeprazole magnesium share of the Ulcer Drug payments more than tripled from 8.0 percent in 2016 to 24.9 percent in 2021.     
  • Dexlansoprazole (Dexilant) is a dual delayed-release drug that combines two different granules in a single 30 or 60 mg capsule, allowing an initial release in the stomach within an hour, and a second release in the small intestine four to five hours later. Dexlansoprazole’s share of the Ulcer Drug prescriptions nearly doubled from 1.1% in 2012 to 2.0% in 2015, then gradually fell to 1.3% in 2020 before rebounding to 1.7% in 2021.  On the other hand, from 2012 to 2018 this drug’s share of the Ulcer Drug payments soared from 1.0% to 6.0%, then retreated to between 5.0% and 5.6% from 2019 through 2021.  From 2012 to 2020, the average payment for a dexlansoprazole prescription climbed steadily from $150 to $380 before dipping to $351 in 2021, as the average number of capsules per prescription increased by about 50% from 2012 to 2020, while the medication remained only available as a single-source brand drug.

 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 III, Musculoskeletal and Ulcer Drugs.   Institute members and subscribers can log on to the Research section of the Institute’s website ( to access this report, as well as Part I of the series, which covered Anti-Inflammatory and Anticonvulsant Drugs, and Part II, which covered Dermatologicals, Opioids, and Antidepressants.  Others can purchase the reports from CWCI’s online store