現今帶狀疱疹後神經痛可提供之藥物療法

Current Pharmacological Treatment of Postherpetic Neuralgia

帶狀疱疹後神經痛，是最常出現於急性帶狀疱疹感染後的合併症。水痘-帶狀皰疹病毒在初次感染人體後，以水痘來作表現。之後病毒就躲在人體的背根神經節伺機而動。再次表現時，就是急性帶狀疱疹感染。帶狀疱疹後神經痛之定義，最常採用的就是在皮疹癒合後3個月以後(包括3個月)仍然在患部感到疼痛或其他之感覺異常，經常導致患者生活品質上很大的影響。在外用藥物上有局部麻醉劑和辣椒素成分之貼布可供使用，不同濃度也有不同之實證療效。在口服藥物方面，目前之治療主流乃是經美國藥物與食品管理局通過適應症之Gabapentinoid，其作用類似類似鈣離子通道阻斷劑；而之前較常使用，但未通過適應症之三環抗憂鬱劑，仍然有其角色，其令人困擾之處在於副作用對於患者生活品質的影響。尤其最常受到帶狀疱疹後神經痛所困擾的正是老年人的族群。類嗎啡類止痛劑在使用上須考慮效用和副作用之間的平衡。目前可採用的療法(包括帶狀疱疹後神經痛適應症及其之外之用藥)很多，但真正能達到相當程度的療效並不是很多。新的藥物研發以及帶狀疱疹疫苗的應用，都是之後相當重要的課題。

Postherpetic neuralgia (PHN) is the most common complication of acute herpes zoster (HZ) infection. Many kinds of medication are currently available for treating PHN; capsaicin and lidocaine are used topically and tricyclic antidepressants (TCAs) are used systemically although because of common adverse effects and the frequent occurrence of the disease in the elderly, TCAs use is gradually decreasing. The current mainstay of treatment and only drug approved by the United States Food and Drug Administration (FDA) for treating PHN is gabapentinoid (a combination of gabapentin and pregabalin). Opioids such as tramadol, morphine, or oxycodone are used as second or even third line therapies, but their overall efficacy is not satisfactory enough. The HZ vaccination has a role in decreasing the incidence and pain of PHN, but its long-term efficacy has yet to be determined. Therefore, much work remains in improving treatment of PHN.