近年在C 型肝炎的治療發展出新一類機轉的藥品，稱為直接作用抗病毒藥物(direct-acting antiviral, DAA)。相較於傳統療法使用長效干擾素 (peginterferon, Peg-IFN) 合併雷巴威林 (ribavirin)，DAA 提供較短的療程、更高的治癒率以及較少的副作用。由於DAA 會影響肝臟酵素 (cytochrome P450, CYP)、乳癌抗藥性蛋白 (breast cancer resistance protein, BCRP)、有機陰離子運輸器 (organic anion-transporting polypeptide, OATP)、P － 醣蛋白 (P-glycoprotein, P-gp) 之功能， 且本身也是其受質或抑制劑，因此與許多藥物都有可能發生藥物交互作用 (drug-drug interactions, DDIs)。在特殊族群病人治療C 型肝炎病毒 (hepatitis C virus, HCV) 感染，除了要考量不同疾病使用的藥物是否會與DAA 產生DDIs，也要考量病人的生理狀態對藥物的影響。本篇文章除了簡介DAA 的機轉及HCV 療程，也根據目前的研究資料探討特殊族群病人的治療與注意事項，這些族群包含肝硬化、腎功能不全、育齡婦女、兒童與青少年、藥物成癮者，以及同時感染人類免疫功能不全病毒、B 型肝炎、肺結核。

A new class of anti-hepatitis C virus (HCV) drugs, or direct-acting antiviral agents (DAAs), have improved HCV treatment outcomes greatly. Compared to the conventional regimens with peginterferon (Peg-IFN) and ribavirin, DAAs have several advantages including shorter treatment duration, higher cure rates and fewer side effects.
However, a number of endogenous enzymes or drug transporters, such as cytochrome P450 (CYP), breast cancer resistance protein (BCRP), organic anion-
transporting polypeptide (OATP) or P-glycoprotein (P-gp), interfere with DAAs pharmacologically and alter treatment outcomes to various extents due to the drug-drug interaction (DDI).
In particular, in HCV patients with certain co-morbidites or other infectious diseases, it is prudent to consider potential DDI between DAAs and drugs taken concurrently for the treatment of underlying diseases. This article discusses antiviral mechanisms of DAAs and treatment regimens, with emphasis on specific populations such as those with cirrhosis or renal insufficiency, women of childbearing age, children and adolescents, drug abusers, and patients with concurrent infections such as human immunodeficiency virus, hepatitis B or tuberculosis.