Treatment for Postherpetic Neuralgia
Postherpetic neuralgia is difficult to treat. Once PHN develops, a multidisciplinary approach that involves a pain specialist, psychiatrist, primary care physician, and other health-care providers may provide the best means to relieve the pain and distress associated with this condition. At this time, some experts recommend the following treatment steps:
- First, topical preparations, usually the lidocaine skin patch (Lidoderm). Effective in many people without producing any known severe side effects.
If that fails:
- Low-dose tricyclic antidepressant, preferably nortriptyline (Pamelor, Aventyl).
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If that fails:
- Gabapentin (an antiseizure agent). Starting with a low dose and increasing it until relief or severe side effects occur.
If that fails:
- Opioids or similar potent painkillers.
These treatments often fail to provide complete pain relief, although they can be very helpful for many patients. Even given the limitations of these proven treatments, one study reported that 70% of older patients with PHN received inappropriate pain medications.
In 2004, the American Academy of Neurology (AAN) issued treatment guidelines for postherpetic neuralgia based on an extensive review of published studies. The AAN recommended tricyclic antidepressants, the anti-convulsants gabapentin and pregabalin, lidocaine patches, and opioids as the most effective treatments for alleviating PHN pain.
Topical Substances for Postherpetic Neuralgia
Topical Pain Relievers. Creams, patches, or gels containing various substances can provide some pain relief.
- Lidocaine and Other Anesthetic Patches. A patch that contains the anesthetic lidocaine (Lidoderm) is approved specifically for postherpetic neuralgia (PHN). The patch appears to reduce pain and improve quality of life for many patients. One to four patches can be applied over the course of 24 hours. Another patch (EMLA) contains both lidocaine and prilocaine, a second anesthetic. These patches are expensive. The most common side effects are skin redness or rash.
- Capsaicin (Zostrix) is prepared from the active ingredient in hot chili peppers. An ointment form has been approved for postherpetic neuralgia. Its benefits are limited, however and it is uncertain whether they are meaningful for most patients. A new patch form that uses a higher than standard dose may be more effective than current options. In one study, it reduced pain by 33% in nearly half of patients. Capsaicin should not be used until the blisters have completely dried out and are falling off the skin. Capsaicin ointment should be handled using a glove, and applied to affected areas three or four times daily. The patient will usually experience a burning sensation when the drug is first applied, but this sensation diminishes with use. It may take up to six weeks for the patient to experience its full effect, however, and about a third cannot tolerate the burning sensation. Many find no benefit.
- Topical Aspirin. Topical aspirin, known chemically as triethanolamine salicylate (Aspercreme) may bring relief.
- Menthol-Containing Preparations. Topical agents containing menthol, such as high-strength Flexall 454, may be helpful.
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