FDA Approves Tonmya: A New, Non-Opioid Option for Fibromyalgia
In August 2025, the U.S. FDA approved sublingual cyclobenzaprine (Tonmya) for use in adults with fibromyalgia. This approval represents the first non-opioid analgesic specifically designed for fibromyalgia patients.
According to the approval, the recommended starting dose is 2.8 mg once daily at bedtime, which may be increased to 5.6 mg after 2 weeks.
Understanding Fibromyalgia
Fibromyalgia is a chronic condition marked by widespread pain, poor sleep, fatigue, and cognitive difficulties often described as “fibro fog.” These symptoms point to dysfunction across multiple biological systems, including the autonomic nervous system and stress-response pathways.
Fibromyalgia has proven to be a disorder of central sensitization. The brain and spinal cord amplify pain signals, making even mild sensations feel overwhelming. Neuroimaging studies show increased activity in pain-processing brain regions, while cerebrospinal fluid analysis reveals elevated substance P levels—a neurotransmitter linked to pain amplification.
Essentially, the brain and spinal cord amplify pain signals, making normal sensations feel overwhelming.
Natural pain-inhibiting pathways involving serotonin, norepinephrine, and endogenous opioids appear impaired in fibromyalgia patients. This creates a perfect storm where pain signals get turned up while the body's natural pain control systems get turned down.
Fibromyalgia as Nociplastic Pain
This central sensitization process makes fibromyalgia a prime example of nociplastic pain. To understand this, we need to recognize three main categories of pain:
Nociceptive pain occurs when tissues are damaged—think of a broken bone or cut finger.
Neuropathic pain results from nerve damage itself, like diabetic neuropathy or sciatica.
Nociplastic pain represents something fundamentally different. There's no obvious tissue damage or nerve injury. Instead, the pain processing system itself becomes hypersensitive and dysfunctional—exactly what happens in fibromyalgia.
The nervous system essentially "turns up the volume" on pain signals. Normal sensations that shouldn't hurt become painful. Light touch might feel like burning. Gentle pressure might feel excruciating. This explains why traditional pain treatments often fail for fibromyalgia patients—anti-inflammatory medications don't help because there's no inflammation to reduce.
Tonmya: A New Treatment Approach for Fibromyalgia
Tonmya represents the fourth FDA-approved medication for fibromyalgia, joining pregabalin, duloxetine, and milnacipran. This sublingual formulation contains cyclobenzaprine, a medication first approved in 1977 for muscle spasm relief.
The starting dose is 2.8 mg once daily at bedtime, with potential increase to 5.6 mg after two weeks. This under-the-tongue delivery system allows rapid absorption and extends the medication's half-life to approximately 36 hours—twice as long as oral cyclobenzaprine.
Structurally similar to tricyclic antidepressants, cyclobenzaprine reduces muscle hyperactivity through central nervous system action. For fibromyalgia patients, benefits likely occur through improved sleep quality.
Cyclobenzaprine itself is not new. The FDA first approved it in 1977 for acute muscle spasm. Structurally similar to tricyclic antidepressants, it reduces muscle hyperactivity through action in the central nervous system. Over time, studies suggested it could also benefit patients with fibromyalgia, likely through improved sleep. Until now, this use was considered off-label and only weakly recommended in guidelines.
The sublingual formulation, Tonmya, was tested in three industry-funded phase 3 trials. Each enrolled about 500 patients and followed them for three months. Two of the trials showed greater improvements in standardized measures of pain, sleep, and fatigue compared to placebo. The average difference in pain scores was modest — less than one point on an 11-point scale — but some patients achieved meaningful reductions. In a third trial, no significant pain difference was observed.
Still, across studies, patients taking Tonmya were more likely to report improved daily function, better sleep, and less fatigue. Its longer half-life (~36 hours compared to 18 hours for generic oral cyclobenzaprine) may play a role in its steady effects.
Tonmya’s side effects are mostly local. The most common are oral numbness (seen in about 23% of patients), tingling, dry mouth, altered taste, and occasional mouth sores. Somnolence affected 6% of patients in the shorter trials but was reported by 18% in a longer safety study. For older adults or those with mild liver impairment, the recommended maximum dose is 2.8 mg daily. Moderate liver impairment is a contraindication.
Insurance Coverage Considerations
Payer coverage for Tonmya remains under determination. Some health plans may offer initial coverage through Medical Exception processes or similar pathways. Following formal coverage policies, certain patients may access Tonmya through Prior Authorization processes.
Integration with Current Practice
This approval provides healthcare providers with another tool for fibromyalgia management alongside existing options. The once-daily bedtime dosing may improve patient compliance compared to multiple daily medications. Healthcare providers should remain alert to potential adverse effects including dizziness and sedation, particularly in older patients.
The medication's extended half-life may benefit patients who struggle with frequent dosing schedules. However, this longer duration also requires careful monitoring for side effects, especially during initial treatment phases.
If you (or someone you know) struggles with fibromyalgia and are (is) seeking options, contact our office to discuss treatment plans, including but not limited to, Tonmya.