【 Pharmacological action 】 Pharmacodynamic sulfamethoxazole is a broad spectrum antibacterial drug, which has antibacterial effect on both gram-positive and Gram-negative bacteria

Yes. Sulfamethoxazole acts on dihydrofolate synthase, interfering with the first step of folate synthesis. Trimethoprim is an antibacterial synergist

In the second step of folic acid synthesis, the action of dihydrofolate reductase is selectively inhibited, so the combination of the two can produce a synergistic effect, which can be reduced

The metabolism of folic acid was doubly blocked, which enhanced the antibacterial effect. The action of sulfa drugs can be influenced by para-aminobenzoic acid and its derivatives (Proca

Is antagonized by, tetracaine). In addition, pus and tissue breakdown products can also provide essential substances for bacterial growth and production of sulfonamides

Antagonism.

pharmacokinetics

Sulfamethostazole is easy to absorb orally, but the absorption is slow, and the excretion in the gastrointestinal tract and urine is slow. So the effective concentration in the blood

The maintenance time is longer. The plasma protein binding rate was low and the acetylation rate was high (50%-70% in goats). Due to the high acetylation rate, and soluble

With low solubility, it is easy to have adverse reactions such as urine formation and hematuria.