病人用藥教育：性不幸福藥關心～藥物引起性功能失調及改善建議（下）

性功能障礙的影響因素很多，評估藥物相關性同時，亦不能排除年齡、疾病、老化等其他加乘因子，多數藥物引起的性功能障礙，在停藥後可獲得改善，少部份尚需靠口服藥物、陰莖注射劑（alprostadil、papaverine + phentolamine）、睾丸激素、陰莖輔具及心理治療等介入。目前用於勃起功能障礙的主流藥物為選擇性第五亞型磷酸雙酯?（phosphodiesterase 5；PDE5）抑制劑，已核准上市的有sildenafil（Viagra?；威而鋼）、vardenafil （Levitra? ；樂威壯）、tadalafil （Cialis?；犀利士 ）三種口服劑型，其中sildenafil（50-100毫克）六星期治療，在改善SSRIs抗鬱劑引起的性功能障礙（勃起功能、興奮、射精、性高潮）有顯著的臨床成果（54.5％ vs 4.4％）。嚴重肝腎功能障礙、大於65歲男性、併用α受體阻斷劑或正服用肝臟CYP3A4抑制代謝藥物等，可能會增加PDE5抑制劑血中濃度，需降低初始劑量。且PDE5抑制劑在治療勃起功能障礙時，可能造成暫時性全身血管擴張，降低血壓，不可與心血管藥物併用，特別是硝酸鹽類。治療決定應以原先疾病控制為優先考量，再納入病人對副作用改善期望，尋求較佳療效並減少不良反應傷害之折衷解決方案。（全文完）

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