Formulations for the treatment of pain

Abstract

Formulations and methods are provided for the treatment of pain, and neuropathic pain in particular. The formulations are eutectic mixtures of a capsaicinoid and a local anesthetic agent and / or an anti-pruritic agent.

Description

CROSS-REFERENCE TO RELATED APPLICATIONS [0001] This application claims priority under 35 U.S.C. §119(e)(1) to provisional U.S. App. Ser. No. 60 / 576,372, filed Jun. 2, 2004, the disclosure of which is incorporated by reference herein.TECHNICAL FIELD [0002] This invention relates generally to the management of pain, and more particularly relates to methods and compositions for the treatment of pain using a eutectic mixture of a capsaicinoid analgesic and a second drug that mitigates the side effects associated therewith. BACKGROUND [0003] Pain is a significant and costly healthcare problem, and is the most common reason patients seek medical care. Pain may be acute or chronic. Examples of acute pain include post-surgical pain and pain due to traumatic injuries. Chronic pain is generally more difficult to treat, and can be associated with any number of causes. For example, chronic pain may be associated with the inflammation of joints, tendons, nerves, muscle, and other soft tissues, w...

AI Technical Summary

Problems solved by technology

Pain is a significant and costly healthcare problem, and is the most common reason patients seek medical care.

Chronic pain is generally more difficult to treat, and can be associated with any number of causes.

Nerves that remain intact following such as disease or injury can become hyperactive, causing pain even in the absence of a direct stimulus.

Unfortunately, neuropathic pain is generally insensitive to administration nonsteroidal anti-inflammatory drugs, which are often successfully prescribed for the treatment of acute pain.

Diabetic neuropathy is a common complication of diabetes mellitus, and can lead to amputation.

Current therapies for neuropathic pain are limited, often involving the administration of multiple medications with the understanding that pain relief will not be complete and the quality of life may not be restored.

These therapies may require frequent dosing, can be associated with undesirable systemic side effects, and typically provide unsatisfactory relief.

Low-concentration capsaicin topical creams have been used for years to treat neuropathic pain, but their use has been limited because they are inconvenient to apply and must be applied at regular intervals throughout the day, even then achieving only modest pain relief at best.

Unfortunately, capsaicin is a potent skin irritant, and the application of capsaicin itself can cause burning pain and hyperalgesia, exacerbating the pain being treated.

This intense initial burning effect usually diminishes after the first few days of application and in most cases disappears with time and continued use; the initial side effects are sufficiently severe, however, to significantly impact on patient compliance, thus diminishing the overall therapeutic value of capsaicin as an effective treatment for pain.

Two-step therapy can be cumbersome for chronic users, however.

Furthermore, because capsaicin is poorly soluble in aqueous solvents, any capsaicin formulation used in this context will have a relatively low concentration of the drug, again requiring frequent application as noted above.

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