Card Set Information
Mechanism of Action
Interfere with bacterial synthesis of folic acid which leads to a decrease in tetrahydrofolic acid which is necessary for purine, thymidine and DNA synthesis.
Good oral bioavailablity
Used to treat Otitis Media and sometimes UTIs (good urine solubility)
Passes into CSF due to minimal protein binding
Used in combination to treat
Low urine solubility
Less solube in urine & slower excretion then sulfisoxazole
Combined with trimethoprim for synergistic bactericidal effect.
Ophthalmic preparation used to treat superficial infections of the eye.
Doesn't penetrate systemically well due to PK.
Broad Spectrum topical sulfa
Used primarily in burn patents
Effective against Pseudomonas
Diffuses well through devascularized areas.
Mafenide and it's metabolite are carbonic anhydrase inhibitiors. (Used with caution in patient with renal or pulmonary insufficiencies)
: Hypersensitivity, fungal colonization, local pain, and burning sensation.
Tropical Sulfa used in burn patients
Effective against pseudomonas
Less pain than with mafenide and few applications needed
Sulfadiazine is absorbed & high concentrations can be achieved.
Crystaluria can be a problem.
Combination of a sulfa and antiinflammatory agent.
Used in treatment of IBD
Poor absorbed from GI tract
Metabolized by bacteria to sulfapyridine and 5-aminosalicylic acid.
Mechanism of Action
Combines two agents that inhibits bacteria synthesis at two sequential steps.
Slow development of resistance
Trimethoprim-Sulfamethoxazole (Bactrim)-Mechanisms of Resistance
Increased production of PABA
Synthesis of altered enzymes
Increased production of dihydropteroate synthetase
Reduced Drug uptake
Trimethoprim-Sulfamethoxazole (Bactrim) - Dosing
Optimal synergistic ratio of serum conc. is 1:20.
Achieved by a fixed dose ratio of 1:5.
Trimethoprim-Sulfamethoxazole (Bactrim) - Spectrum of Activity
Gram Positive - MSSA, MRSA, S. epidermidis, S. pneumoniae.
Gram Negative - Most enterobacteriaceae, H. flu, M. catarrhalis, Salmonella, Shigella
Not active againist Pseudomonas and poor anaerobic coverage.