先せん発ぱつ薬やく

noun

original drug; originator drug

Pharmaceutical term for a brand-name drug that was developed and marketed first, before generic versions. Often contrasted with 後発薬 (generic drug).

See also: 先発医薬品

• 先せん発ぱつ薬やくの特とっ許きょが切きれると、後こう発はつ薬やくが市し場じょうに出で回まわる。

  When the patent on the original drug expires, generic drugs enter the market.