The US FDA has given its nod for Qutenza (capsaicin) skin patch for treating pain caused by postherpetic neuralgia (PHN) i. e. shingle-related pain.
Excruciating, PHN pain is often described as a burning, stabbing, or gnawing pain, starting with an attack of shingles, in which the herpes zoster virus i. e. the chickenpox virus, which lying dormant at nerve roots is reactivated.
PHN pain persists even after the shingles scales have healed and affects 10% to 15% of people with shingles. While, it may get better over time, it also may not, and treatments include prescription pain medications, anti-convulsants, and anti-depressants.
Capsaicin is a compound found in chili peppers and is responsible for causing the heat sensation, and the Qutenza 8 percent patch offers relief by delivering a synthetic version of capsaicin to the skin area experiencing the nerve pain.
Effectively, clinical studies show a one-hour application of four Qutenza patches can reduce PHN pain up to 12-weeks, patches which can be cut to conform to the areas of pain. NeurogesX says, there are no side-effects to the non-narcotic medication, as it is not only unlikely to cause drowsiness, it also does not interact with other drugs.
Qutenza is applied by a doctor via a patch or patches for 1-hour and before applying the patch the doctor spreads a topical anesthetic on the area to be treated. After the patch is removed, for a few days the treated areas may be sensitive to heat from hot showers, sunlight, or vigorous exercise.
The most common side effects reported during the clinical trials, was a redness of the skin at the application site, including itching and an increase in blood pressure that can last for two hours after treatment. While, Qutenza is not a cure for PHN, clinical trials have shown that 40% to 50% of treated patients reported their pain to be 30% less severe.
According to San Francisco-based NeurogesX, Qutenza most likely will be available in USA in the first quarter of next year. Qutenza may be used in combination with other PHN treatments and can be repeated every three months.