商品名：Omnipen, Principen, Totacillin, and Polycillin
Beta-lactam antibiotic. Ampicillin inhibits bacterial cell wall synthesis. Ampicillin has a narrow spectrum of activity that is similar to that of amoxicillin. Ampicillin generally has a spectrum of activity that includes streptococci, non-beta-lactamase– producing staphylococci, and many other gram-positive cocci and bacilli. Many staphylococci are resistant owing to beta-lactamase production. Most enteric gram-negative bacilli of the Enterobacteriaceae are resistant. Susceptible gram- negative bacteria include some species of Proteus, Pasteurella multocida, and Histophilus. Resistance among
Ampicillin is indicated in patients with infections caused by susceptible bacteria, such as skin and soft tissue infections, UTIs, and pneumonia. Gram-positive bacteria (except beta-lactamase–producing strains of Staphylococcus) are usually susceptible. Ampicillin, Ampicillin Sodium 43 A However, infections caused by most gram-negative bacteria (exept Pasteurella) are usually resistant.
劑量數字暫停提供：VetPro 的劑量改依 DRUGAPI 藥物資料庫對外的內容，DRUGAPI 目前不提供可直接計算的劑量。下方列出 DRUGAPI 的審查結論與劑量審查引用的來源；計算機可手動輸入劑量換算。
啟用前必須同時鎖定 ampicillin 活性成分、鹽型或水合型、強度基準、精確商品與申請、濃度或強度、劑型、途徑、物種、感染部位、病原與藥敏、病人過敏與腎肝及生殖狀態、食物鏈、法域、雙向交互作用紀錄、調配使用期限與保存。
DRUGAPI 劑量審查引用的獸醫官方標示（各標示只適用於其產品、物種與法域，不可互換）
依出現頻率分組；嚴重副作用獨立列出，臨床上需立即辨識。