In 2010, five inventors filed a patent for a sustained-release version of Flexeril for tinnitus. Anyone interested in this drug should read the patent information. According to the inventors, better efficacy is obtainable through a sustained-release formulation of the drug.
Here are some extracts from the patent application, published in 2013:
Treatment of tinnitus and related auditory dysfunctions
ABSTRACT
The invention provides an extended-release dosage form of cyclobenzaprine for use in the treatment of tinnitus and related auditory dysfunctions by once-a-day oral administration, wherein the dosage form is a tablet or capsule comprising cyclobenzaprine as active agent in an amount from 10-80mg, preferably from 10- 60mg. The active agent is associated with a polymer coating or matrix that comprises a water-insoluble polymer, the polymer coating or matrix providing the dosage form with an extended release of the active agent over at least 12 hours and preferably over at least 16 hours when the dosage form is administered to a patient.
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Cyclobenzaprine is a skeletal muscle relaxant. The exact mechanism of action for cyclobenzaprine is unknown. Current research appears to indicate that cyclobenzaprine acts on the locus coeruleus where it results in increased norepinephrine release, potentially through the gamma fibers which innervate and inhibit the alpha motor neurons in the ventral horn of the spinal cord. Decreased firing of the alpha motor neuron results in decreased muscular tone.
Cyclobenzaprine is a muscle relaxant acting primarily on the central nervous system. It is structurally similar to Amitriptyline, differing by only one double bond. Cyclobenzaprine is typically prescribed to relieve pain and muscle spasms. Typically, muscle spasms occur in an injury to stabilize the affected body part and prevent further damage. Whereas this is beneficial in acute injury, muscle spasm frequently persists over time, becomes dysfunctional and can increase the pain level. It is believed that by decreasing muscular spasm, pain is diminished. A common application would be that of a whiplash injury in a car accident.
Cyclobenzaprine has also been studied in the treatment of fibromyalgia. In a study of 120 fibromyalgia patients, those receiving Cyclobenzaprine (10 to 40 mg) over a 12 week period had significantly improved quality of sleep and pain score. Interestingly, there was also a reduction in the total number of tender points and muscle tightness. It is also prescribed off-label as a sleeping-aid.
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As-yet unpublished PCT patent application PCT/IB2010/051373, filed 30 March 2010,
relates to cyclobenzaprine for use in the treatment of tinnitus and related auditory dysfunctions by oral administration or by parenteral administration through intramuscular, intravenous, subcutaneous or intrathecal injection or infusion, and presents data demonstrating the efficacy of cyclobenzaprine for these treatments.
This unpublished PCT patent application mentions the use of extended release cyclobenzaprine for tinnitus by once-a-day administration but does not provide any details thereupon, neither of the means for providing extended release, nor any other details. Background art on extended-release drug formulations.
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As shown by the tests reported below, which are taken over from the above- mentioned PCT patent application PCT/IB2010/051373,
cyclobenzaprine has a positive effect on tinnitus severity and on tinnitus loudness in the tested subjects, it is safe to administer and though common side effects (like constipation and dry mouth) may be experienced, it is tolerated well by most subjects. Similar results are expected for associated auditory dysfunctions. Generally, according to the invention, the described extended release form of cyclobenzaprine is effective for the treatment of an auditory dysfunction selected from tinnitus, hyperacusis, auditory hallucinations, misophonia, phonophobia and central auditory processing disorders. General aspects of extended-release cyclobenzaprine for treating tinnitus
For many chronic conditions such as chronic pain, management guidelines recommend the use of long-acting, extended-release formulations. Guidelines for pharmacological treatment of tinnitus however have not been established, although tinnitus is a chronic condition. As such, the goal of pharmacological therapy for tinnitus is to provide sustained relief.
The use of long-acting, extended-release formulations for tinnitus is desirable because they provide prolonged, more consistent plasma concentrations of drug compared with short-acting agents, thus minimizing fluctuations that could contribute to end-of-dose breakthrough tinnitus. In this regard, a randomized, open-label, two-period crossover, single-centre study, has demonstrated that single-dose pharmacokinetics of once-daily cyclobenzaprine extended release 30 mg versus cyclobenzaprine immediate release 10 mg three times daily in healthy young adults, provides a controlled release of cyclobenzaprine with sustained plasma concentrations, in contrast to the fluctuating profile of cyclobenzaprine immediate release with comparable systemic exposures.
Better efficacy and fewer side effects
[emphases added]
Reference:
http://www.google.com/patents/EP2621475A1?cl=en
Here's a summary of the patent's history:
If anyone takes this new formulation, please let us know!