Keng spektrli ta'sirga ega beta-laktam antibiotik.
Bakteriyalarning hujayra devori sintezini ingibitsiya qiladi va grammusbat, grammanfiy mikroorganizmlar, aerob va anaeroblarga nisbatan bakteritsid ta’sir ko‘rsatadi. Imipenem tiyenaminning hosilasi bo‘lib, karbapenemlar guruhiga kiradi. Silastatin natriy buyraklarda imipenemni metabolizatsiya qiluvchi ferment – degidropeptidazani ingibitsiya qiladi, bu esa o‘zgarmagan imipenemning siydik yo‘llaridagi konsentratsiyasini sezilarli darajada oshiradi. Silastatinning o‘zida antibakterial faollik yo‘q va bakteriyalarning beta-laktamazasini ingibitsiya qilmaydi. Imipenem Pseudomonas aeruginosa, Staphylococcus aureus, Streptococcus faecalis va Bacteroides fragilis ga nisbatan faol. Bakteriyalarning beta-laktamazasiga nisbatan barqaror, bu esa uni Pseudomonas aeruginosa, Serratia spp., Enterobacter spp. kabi ko‘plab beta-laktam antibiotiklarga chidamli mikroorganizmlarga nisbatan samarali qiladi.
Antibakterial spektri deyarli barcha klinik ahamiyatga ega bo‘lgan patogen mikroorganizmlarni o‘z ichiga oladi. Quyidagi grammanfiy aerob bakteriyalarga nisbatan faol: Achromobacter spp., Acinetobacter spp. (ilgari Mima-Herellea), Aeromonas hydrophila, Alcaligenes spp., Bordetella bronchicanis, Bordetella bronchiseptica, Bordetella pertussis, Brucella melitensis, Campylobacter spp., Capnocytophaga spp., Citrobacter spp. (shu jumladan Citrobacter diversus, Citrobacter freundii), Eikenella corrodens, Enterobacter spp. (shu jumladan Enterobacter aerogenes, Enterobacter agglomerans, Enterobacter cloacae), Escherichia coli, Gardnerella vaginalis, Haemophilus ducreyi, Haemophilus influenzae (beta-laktamaza hosil qiluvchi shtammlar), Haemophilus parainfluenzae, Hafnia alvei, Klebsiella spp. (shu jumladan Klebsiella oxytoca, Klebsiella ozaenae, Klebsiella pneumoniae), Moraxella spp., Morganella morganii (ilgari Proteus morganii), Neisseria gonorrhoeae (shu jumladan penitsillinaza hosil qiluvchi shtammlar), Neisseria meningitidis, Yersinia spp. (ilgari Pasteurella), shu jumladan Yersinia multocida, Yersinia enterocolitica, Yersinia pseudotuberculosis; Plesiomonas shigelloides, Proteus spp. (shu jumladan Proteus mirabilis, Proteus vulgaris), Providencia spp. (shu jumladan Providencia alcalifaciens, Providencia rettgeri (ilgari Proteus rettgeri), Providencia stuartii), Pseudomonas spp. (shu jumladan Pseudomonas aeruginosa, Pseudomonas fluorescens, Pseudomonas pseudomallei, Pseudomonas putida, Pseudomonas stutzeri), Salmonella spp. (shu jumladan Salmonella typhi), Serratia spp. (shu jumladan Serratia marcescens, Serratia proteamaculans), Shigella spp.
Grammusbat aerob bakteriyalarga nisbatan faol: Bacillus spp., Enterococcus faecalis, Erysipelothrix rhusiopathiae, Listeria monocytogenes, Nocardia spp., Pediococcus spp., Staphylococcus aureus (shu jumladan penitsillinaza hosil qiluvchi shtammlar), Staphylococcus epidermidis (shu jumladan penitsillinaza hosil qiluvchi shtammlar), Staphylococcus saprophyticus, Streptococcus agalactiae, Streptococcus pneumoniae, Streptococcus pyogenes, Streptococcus C guruhi, Streptococcus G guruhi, yashil streptokokklar, shu jumladan alfa- va gamma-gemolitik shtammlar.
Grammanfiy anaerob bakteriyalarga nisbatan faol: Bacteroides spp., Bilophila wadsworthia, Fusobacterium spp., Porphyromonas asaccharolytica, Prevotella spp., Veillonella spp.
Grammusbat anaerob bakteriyalarga nisbatan faol: Actinomyces spp., Bifidobacterium spp., Clostridium spp., Eubacterium spp., Lactobacillus spp., Peptococcus spp., Peptostreptococcus spp., Propionibacterium spp.
Ba'zi mikroorganizmlar: Mycobacterium fortuitum, Mycobacterium smegmatis.
Ba'zi Staphylococcus spp. (metitsillinga chidamli), Streptococcus spp. (D guruhi), Stenotrophomonas maltophilia, Enterococcus faecium va ba'zi Pseudomonas cepacia shtammlari imipenemga chidamli. U ko‘pgina tsefalosporinlar, aminoglikozidlar va penitsillinlar ga chidamli bakteriyalar keltirib chiqaradigan ko‘plab infeksiyalarga qarshi samaralidir. In vitro da ba'zi Pseudomonas aeruginosa shtammlariga qarshi aminoglikozidlar bilan sinergistik ta’sir ko‘rsatadi.