unasyn unasyn unasyn is the trade name for two related antibiotic drugs: ampicillin/sulbactam, a fixed-dose combination medication of the penicillin antibiotic combination ampicillin/sulbactam sultamicillin, an oral form of the penicillin antibiotic combination ampicillin/sulbactam this article is issued from wikipedia. the text is licensed under creative commons - attribution - sharealike. additional terms may apply for the media files.