Therapy procedure for drug delivery for trigeminal pain

Abstract

The present invention relates to methods for the treatment or prevention of trigeminal nerve-associated pain, in particular chronic, acute and procedural-related pain. The methods comprise administration of analgesic agents to the trigeminal nerve system which results in analgesia to the facial or head region.

Description

CROSS-REFERENCE TO RELATED APPLICATIONS [0001] The application is related to and claims the benefit of U.S. Provisional Patent Application Ser. No. 60 / 711,950, filed Aug. 26, 2005, and U.S. Provisional Patent Application Ser. No. 60 / 794,004, filed Apr. 21, 2006, the entire contents of which are hereby incorporated by reference herein in their entirety.TECHNICAL FIELD [0002] The present invention relates generally to methods and compositions for the treatment of pain. More specifically, the present invention relates to methods for the treatment or prevention of trigeminal nerve-associated procedural, acute and chronic pain by administration and targeted delivery of analgesic agents to the trigeminal nerve system resulting in localized pain relief with minimal untoward central nervous system effects or systemic side effects. BACKGROUND OF THE INVENTION [0003] Pain is experienced when the free nerve endings which constitute the pain receptors in the skin as well as in certain internal ...

AI Technical Summary

Problems solved by technology

Ineffectively treated pain can be devastating to the person experiencing it by limiting function, reducing mobility, complicating sleep, and dramatically interfering with the quality of life.

Pain involving the trigeminal nerve and ganglion arises in many different medical situations and presents unique problems to pain therapists and doctors.

Further, medical procedures such as common dental work and facial plastic and / or cosmetic surgery may elicit considerable pain, as well as discomfort and anxiety.

The treatments generally have limited efficacy and many patients eventually undergo an invasive procedure.

The pain relief from these procedures can be successful in a percentage of these patients, but the relief can be short-lived and often facial pain returns.

Significant procedural pain and long term morbidity may also be associated with such treatments.

Drug treatments for ATFP are similar to what is prescribed for trigeminal neuralgia including anti-seizure medications and tricyclic antidepressants with limited effectiveness.

Pressure and “heaviness” can also be part of the pain symptoms and often there is eye pain.

Cold can increase the feeling of numbness sometimes making the face feel frozen.

Opioid therapy has a multitude of problems including systemic effects away from the site of pain stimulation.

Furthermore, opioids are highly addictive and patients build up tolerance to the drugs quickly resulting in higher and higher doses being administered.

Pain intensity is moderate to severe and can be debilitating and often causes nausea and vomiting.

Many of these drugs have systemic side effects and limited effectiveness.

In addition to the pain of administration, another main disadvantage of local anesthetics, especially for routine dental procedures, is that numbness and loss of sensation in the facial region will usually last for several hours after the dental procedure is finished.

For many of these procedures local anesthetics are used (the patients are not under general anesthetic) and as with dental procedures, the local anesthetics can be painful to administer and include the problem of lingering numbness lasting for hours after the procedure is finished.

In addition, depending on the surgery performed, patients experience varying levels of post-operative pain after the anesthetic wears off.

However, their usefulness is limited by the tolerance and dependence that normally develops on chronic treatment.

Opioid drugs such as morphine can be addictive and can have central nervous system-mediated side effects such as respiratory and cardiac depressions and drowsiness.

Additionally, opioid drugs suffer from frequent side effects such as nausea, vomiting and constipation.

For patients suffering procedural, acute or chronic pain associated with the trigeminal nerve, one of the main problems with conventional drug delivery with analgesic agents is the lack of localized pain relief due to systemic distribution of the agent.

With higher doses of an analgesic agent, there is the additional problem of limited efficacy relative to the increase in undesired side effects due to the systemic distribution of the agent.

Treatments consisting of localized but invasive interventions directly to the trigeminal nerve have a significant disadvantage due to the lack of selectivity and / or reversibility of the intervention and the fact that these procedures can, by themselves, cause additional facial nerve problems including anesthesia doloroso, persistent numbness and nerve deafferentation.

An additional problem with conventional treatments for trigeminal nerve-associated pain, especially with invasive procedures, is the high level of skill, training and equipment required by the medical team which can make treatment expensive and impractical for widespread use.

However, while there is evidence that various therapeutic agents can be delivered to the brain by an intranasal route and that the agents may travel along perineural pathways, there is no known method utilizing these pathways to specifically target the trigeminal nerve system for localized or regional analgesia in individuals suffering from trigeminal nerve-associated pain.

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