After more than a decade and a half without a new treatment option, the FDA approved Tonmya (cyclobenzaprine HCl sublingual tablets) last August for the treatment of fibromyalgia in adults. The drug is now commercially available in U.S. pharmacies, and workers’ compensation professionals should expect to see it appearing in treatment plans — bringing with it a fresh set of questions about medical necessity, cost, and the ever-contentious issue of fibromyalgia in the workers’ comp system.
Fibromyalgia is one of the most divisive diagnoses in workers’ compensation. It affects an estimated 10 million adults in the United States — roughly 80 percent of them women — and is characterized by chronic widespread pain, nonrestorative sleep, fatigue, morning stiffness, and cognitive difficulties often described as “fibro fog.” There is no objective diagnostic test. No blood marker. No imaging finding. Diagnosis relies on clinical criteria established by the American College of Rheumatology, centering on patient-reported symptoms. That diagnostic profile has made fibromyalgia claims a persistent source of friction between claimants, employers, insurers, and medical evaluators.
Until now, treating physicians have had only three FDA-approved medications to work with: pregabalin (Lyrica), approved in 2007; duloxetine (Cymbalta), approved in 2008; and milnacipran (Savella), approved in 2009. All three have significant limitations. Many patients do not respond adequately, and side-effect profiles often lead to discontinuation. Some treating physicians have resorted to off-label prescribing — including opioids — to manage symptoms, adding another layer of complexity and risk to these claims.
Tonmya is the fourth FDA-approved treatment and the first new approval since 2009.
Tonmya is a sublingual (under-the-tongue) formulation of cyclobenzaprine hydrochloride. Workers’ comp professionals will recognize cyclobenzaprine immediately — it is one of the most commonly prescribed muscle relaxants in the system, marketed for decades under the brand name Flexeril for short-term treatment of acute muscle spasms. But Tonmya is not simply a repackaged Flexeril. The sublingual delivery method is a deliberate design choice. By dissolving under the tongue, the drug is absorbed directly through the oral mucosa into the bloodstream, bypassing the liver’s first-pass metabolism. This reduces production of norcyclobenzaprine, a long-acting metabolite associated with next-day grogginess — a common complaint with oral cyclobenzaprine.
Tonmya is taken once daily at bedtime. Its mechanism of action in fibromyalgia is not fully understood, but it acts on multiple receptor systems involved in pain modulation and sleep regulation, including serotonin, adrenergic, histamine, and muscarinic receptors. Critically, it is a non-opioid therapy. In an era where workers’ comp systems across the country are actively working to reduce opioid utilization in chronic pain management, a new non-opioid option for a condition that frequently drives opioid prescribing is noteworthy.
The FDA approval was supported by three randomized, double-blind, placebo-controlled trials involving a total of 1,474 patients who met current ACR diagnostic criteria for fibromyalgia. The Phase III RELIEF and RESILIENT trials demonstrated that Tonmya significantly reduced daily pain scores compared to placebo over 14 weeks, with a clinically meaningful proportion of patients achieving at least 30 percent pain improvement. The trials also showed improvements in sleep quality, fatigue, and daily function — symptoms that directly affect an injured worker’s ability to perform job duties and participate in rehabilitation.
The arrival of Tonmya raises several practical issues for the claims industry. Expect to see it on bills. Now that Tonmya is commercially available, treating physicians who diagnose fibromyalgia in injured workers — whether as a primary condition or a complication of a workplace injury — will have a new prescribing option. Claims adjusters, utilization review professionals, and bill review teams should familiarize themselves with the drug, its approved indication, and its clinical profile. As a brand-name medication with patent exclusivity extending to at least 2034, Tonmya will carry a higher price point than generic cyclobenzaprine or the older approved alternatives, and cost inquiries from payers are inevitable.