FDA Approves New Drug For Pain That Persists After Shingles

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Main Category: Infectious Diseases / Bacteria / Viruses
Also Included In: Neurology / Neuroscience;  Dermatology;  Seniors / Aging
Article Date: 18 Nov 2009 - 11:00 PST

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The US Food and Drug Administration (FDA) announced yesterday that it has approved Qutenza (capsaicin) 8% patch for the treatment of post-herpetic neuralgia (PHN), an often excruciating pain that can persist for weeks, months and even years in 10 to 15 per cent of people who get shingles.

The medicated skin patch, which is made by Lohmann Therapie-Systems AD of Andernach, Germany and distributed in the US by NeurogesX Inc. of San Mateo, California, has to be applied by a health care professional because it is painful to apply and the patient needs to have a local anasthetic first.

Patients will probaby also need additional pain relief such as ice or opioids and should be monitored for at least an hour afterwards because there is a risk of high blood pressure occuring after the patch is applied.

Dr Bob Rappaport, director of the Division of Anesthesia, Analgesia and Rheumatology Products in the FDA's Center for Drug Evaluation and Research told the press that:

"This new product can provide effective pain relief for patients who suffer from PHN."

Dr Lynn Webster, Medical Director, Lifetree Clinical Research, Salt Lake City, Utah said:

"PHN can be an excruciatingly painful condition that can affect many aspects of a patient's quality of life."

She explained that undesirable side effects often limit the use of many of the currently available pain control drugs and therefore, the treatment of PHN continues to "represent a significant unmet need".

"Qutenza may provide a unique treatment option that works at the site of the pain and may be useful as a treatment option in combination with existing therapies," she added.

Shingles is caused by the the varicella-zoster virus, the same virus that causes chickenpox. Anyone who has had chickenpox carries the virus and is at risk of shingles if the virus is reactivated, usually along one nerve. The outbreak lasts for 2 to 4 weeks and often starts with a dull or burning pain local to the affected nerve.

The first visible symptoms of shingles often include an outbreak of rash and/or blisters on the skin. A typical outbreak appears like a band of welts and blisters from the back to the front of the torso or abdomen. The upper face, including the eye, is another common site.

PHN affects the nerve fibers and skin and the pain, which can be excruciating can last weeks, months and even years. About 10 to 15 per cent of people who have shingles get PHN, which tends to be more common in elderly patients.

The active ingredient in Qutenza is capsaicin, a compound that makes chilli peppers taste hot.

You can get over the counter products marketed for the relief of PHN: these contain lower concentrations of capsaicin than Qutenza which according to the FDA is the first prescription drug to contain a pure, concentrated, synthetic form of capsaicin to gain federal approval.

Evidence from clinical studies showed that Qutenza lessened PHN pain for up to 12 weeks following a single one-hour treatment. Treatment can be repeated every 3 or more months.

The most frequently reported side effects included pain, swelling, itching, redness and bumps at the site where the patch is applied.

Elevated blood pressure occurred in some patients, and on average this was less than 10 mm Hg, although for some patients the increase was higher, and lasted for about two hours after the patch was removed.

Qutenza has also been approved in the European Union.

Sources: FDA, NeurogesX.

Written by: Catharine Paddock, PhD
Copyright: Medical News Today
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