of bacterial groups, including Staphylococcus aureus, Enterobacteriaceae, and anaerobic bacteria. Importantly, it is not active against Pseudomonas aeruginosa and should not be used alone when infection with this organism is suspected or known. History The introduction and use of ampicillin alone started in 1961. The development and introduction of this drug allowed the use of targeted therapies against gram-negative bacteria. With the rise of beta-lactamase producing bacteria, ampicillin and the other penicillin-derivatives became ineffective to these resistant organisms. With the introduction of beta-lactamase inhibitors such as sulbactam, combined with ampicillin made beta-lactamase producing bacteria susceptible. Formulation Ampicillin-sulbactam only comes in a parenteral formulation to be either used as intravenous or intramuscular injections, and can be formulated for intravenous infusion. It is formulated in a 2:1 ratio of ampicillin:sulbactam. The commercial preparations available include: 1.5 grams (1 gram ampicillin and 0.5 gram sulbactam) →Brand names: Unasyn, Unasyn ADD-Vantage, Unasyn Piggyback 3 grams (2 grams ampicillin and 1 gram sulbactam) →Brand names: Unasyn, Unasyn ADD-Vantage, Unasyn Piggyback 15 grams (10 grams ampicillin and 5 grams sulbactam) →Brand name: Unasyn Society and culture Names Unasyn (US) Subacillin (Taiwan) Unictam (Egypt) Ultracillin (Egypt) Fortibiotic Sulbin (Egypt) Novactam (Egypt) Sulbacin (Kenya) References External links Penicillins Combination antibiotics Pfizer brands