先せん発ぱつ薬やくせんぱつやくじ字FuriganaMeanings1nounoriginal drug; originator drugPharmaceutical 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