Sulfamethoxazole Pharmacokinetics

Absorption:

Sulfamethoxazole is well-absorbed if administered topically. It is rapidly captivated if it is orally administered.

Distribution:

Sulfamethoxazole distributes into a lot of physique tissues as able-bodied as into sputum, vaginal fluid, and average ear fluid.It aswell crosses the placenta. About 70% of the biologic is apprenticed to claret proteins. Its Tmax (or time to ability best biologic absorption in plasma) occurs 1 to 4 hours afterwards articulate administration. The beggarly serum half-life of sulfamethoxazole is 10 hours.However, the half-life of the biologic acutely increases in humans with creatinine approval ante according to or beneath than 30 mL/minute. A half-life of 22–50 hours has been appear for humans with creatinine clearances of beneath than 10 mL/minute.

Metabolism:

Sulfamethoxazole is metabolized in the animal alarmist to at atomic 5 metabolites. These metabolites are the N4-acetyl-, N4-hydroxy-, 5-methylhydroxy-, N4-acetyl-5-methylhydroxy-sulfamethoxazole metabolites, and an N-glucuronide conjugate. The CYP2C9 agitator is amenable for the accumulation of the N4-hydroxy metabolite. In vitro studies advance sulfamethoxazole is not a substrate of the P-glycoprotein transporter.

Excretion:

Sulfamethoxazole is primarily renally excreted via glomerular filtration and tubular secretion. About 20% of the sulfamethoxazole in urine is the banausic drug, about 15-20% is the N-glucuronide conjugate, and about 50-70 % is the acetylated metabolite. Sulfamethoxazole is aswell excreted in animal milk.