trimethoprim, Trimpex (Discontinued Brand), Proloprim (Discontinued Brand), Primsol

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GENERIC NAME: trimethoprim

BRAND NAMES: Trimpex (Discontinued Brand), Proloprim (Discontinued Brand), Primsol

DRUG CLASS AND MECHANISM: Trimethoprim is a synthetic (man-made) antibiotic that interferes with the production of tetrahydrofolic acid, a chemical that is necessary in order for bacteria and human cells to produce proteins. Trimethoprim inhibits production of tetrahydrofolic acid by inhibiting the enzyme responsible for making tetrahydrofolic acid from dihydrofolic acid. Trimethoprim inhibits the bacterial enzyme more than the human enzyme. Therefore, trimethoprim has less effect on the production of tetrahydrofolic acid by humans. Because of the frequent development of resistance to trimethoprim, it is more effective when combined with another antibiotic, sulfamethoxazole (Azo-Gantanol), and is rarely used alone. Trimethoprim was first approved by the FDA in combination with sulfamethoxazole (for example, Bactrim, Septra) in 1973. It was approved as a stand-alone drug in 1980.



PREPARATIONS: Tablets: 100 and 200 mg. Solution: 50 mg/5 ml

STORAGE: Tablets should be stored at room temperature, 15-30 C (59-86 F).

PRESCRIBED FOR: Trimethoprim is used for the treatment of uncomplicated urinary tract infections due to susceptible bacteria.

DOSING: The usual dose is 100 mg every 12 hours or 200 mg every 24 hours for 10 days. As with all antibiotics, it is important to complete the entire course of trimethoprim even if symptoms improve early during therapy. Persons with kidney diseases may need to receive lower doses since diseased kidneys may not eliminate trimethoprim adequately from the body, and levels of trimethoprim may increase in the body and lead to side effects.

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