Kombinatsiyalangan antibakterial preparat bo'lib, tarkibida sulfametoksazol va trimetoprim mavjud. Sulfametoksazol para-aminobenzoy kislotasi (PABK) bilan tuzilish jihatidan o'xshash bo'lib, bakteriya hujayralarida dihidrofoliy kislotasi sintezini buzadi, PABK ni uning molekulasiga qo'shilishiga to'sqinlik qiladi. Trimetoprim esa sulfaning ta'sirini kuchaytirib, dihidrofoliy kislotaning tetrahidrofoliy kislotaga — foliy kislotasining faol shakliga aylanishini buzadi, bu mikroblar hujayralarining bo'linishi va oqsil almashinuviga javob beradi. Preparat keng spektrli bakteritsid ta'sirga ega.
Quyidagi mikroorganizmlarga qarshi faol:
Streptococcus spp. (gemolitik shtammlar penitsillinga ko'proq sezgir),
Staphylococcus spp.,
Streptococcus pneumoniae,
Neisseria meningitidis,
Neisseria gonorrhoeae,
Escherichia coli (jumladan, enterotoksigenik shtammlar),
Salmonella spp. (jumladan, Salmonella typhi va Salmonella paratyphi),
Vibrio cholerae,
Bacillus anthracis,
Haemophilus influenzae (jumladan, ampisillinga chidamli shtammlar),
Listeria spp.,
Nocardia asteroides,
Bordetella pertussis,
Enterococcus faecalis,
Klebsiella spp.,
Proteus spp.,
Pasteurella spp.,
Francisella tularensis,
Brucella spp.,
Mycobacterium spp. (jumladan, Mycobacterium leprae),
Citrobacter spp.,
Enterobacter spp.,
Legionella pneumophila,
Providencia spp.,
ayrim Pseudomonas spp. (lekin Pseudomonas aeruginosaga nisbatan emas),
Serratia marcescens,
Shigella spp.,
Yersinia spp.,
Morganella spp.,
Pneumocystis carinii,
Chlamydia spp. (jumladan, Chlamydia trachomatis va Chlamydia psittaci).
Shuningdek, prosteishlar:
Plasmodium spp.,
Toxoplasma gondii,
Actinomyces israelii,
patogen zamburug'lar:
Coccidioides immitis,
Histoplasma capsulatum,
Leishmania spp.
Preparatga chidamli mikroorganizmlar:
Corynebacterium spp.,
Pseudomonas aeruginosa,
Mycobacterium tuberculosis,
Treponema spp.,
Leptospira spp.,
viruslar.
Preparat ichak tayoqchasi faoliyatini bostiradi va ichakda tiamin, riboflavin, nikotin kislotasi va B guruhi vitaminlari sintezining kamayishiga olib keladi. Terapevtik ta'siri 7 soat davom etadi.