sulfamethoxazole and trimethoprim, Bactrim, Septra
GENERIC NAMES: Sulfamethoxazole and trimethoprim; cotrimoxazole
BRAND NAMES: Bactrim, Bactrim DS, Septra DS, Sulfatrim
DISCONTINUED BRAND: Septra
DRUG CLASS AND MECHANISM: Bactrim is a combination of two synthetic (man-made) antibiotics, sulfamethoxazole and trimethoprim. Both drugs reduce the ability of some bacteria to utilize folic acid for growing. Sulfamethoxazole is an anti-bacterial sulfonamide, a "sulfa" drug. It disrupts the production of dihydrofolic acid while trimethoprim disrupts the production of tetrahydrofolic acid. Dihydrofolic acid and tetrahydrofolic acid are forms of folic acid that bacteria and human cells use for producing proteins. Trimethoprim inhibits production of tetrahydrofolic acid by inhibiting the enzyme responsible for making tetrahydrofolic acid from dihydrofolic acid. By combining both drugs, two important steps required in the production of bacterial proteins are interrupted, and the combination is more effective than either drug alone. Bactrim was approved by the FDA in 1973.
Medically Reviewed by a Doctor on 1/21/2015
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