Postherpetic neuralgia: Therapeutic and prophylactic aspects and pregabalin therapy

Abstract

Postherpetic neuralgia (PHN) is one of the most common and persistent chronic pain syndromes caused by chickenpox virus affecting the peripheral and central nervous systems. PHN is a typical neuropathic pain resulting from injury or dysfunction of the somatosensory system whose development involves a few mechanisms. Elderly people are more prone to PHN, which is associated with the weakened immune system. Treatment of shingles cannot completely prevent subsequent neuralgia; however, some drugs can reduce its manifestations. The diagnosis of PHN is largely based on the duration of pain after rash onset. However, it is difficult to estimate the real rate of PHN development because there is neither consensus of opinion on this issue nor common criteria for pat duration (1 to 6 months, as shown by different data). The significant factors that may predispose to PHN are older age, female gender, and acute herpes zoster indicators, such as pain intensity, the severity of herpetic rash and infectious manifestations. Pain syndrome in PHN can reach a high intensity level, accompanied by the development of chronic fatigue, depression, and loss of social skills. There are several types of pain in PHN: constant, paroxysmal and allodynia, which are due to different pathophysiological mechanisms. Variability in the clinical manifestations of PHN may underlie the inadequate efficacy of one or other drug. The treatment of PHN poses definite difficulties. About 40-50% of patients continue to suffer from pain despite the fact that the multitude of currently available therapies is performed. Pregabalin, whose high efficacy and advantages in the treatment of pain in PHN are demonstrated in numerous studies, is one of the most effective first-line drugs for PHN. In-depth analysis suggests that inadequately low doses of pregabalin are frequently used in the treatment of PHN, which may lead to an insufficient analgesic effect.