Trimetriprim

Trimetriprim is a synthetic antibacterial drug that belongs to the sulfonamide class. It is a diaminopyrimidine derivative. Trimetriprim functions by inhibiting dihydrofolate reductase, an enzyme essential for the synthesis of folic acid in bacteria. Folic acid is a crucial component in the production of nucleic acids and proteins, and its depletion leads to bacterial cell death. Trimetriprim is often used in combination with sulfamethoxazole, a sulfa drug that inhibits an earlier step in the folic acid synthesis pathway. This combination, known as trimethoprim/sulfamethoxazole or TMP/SMX, exhibits a synergistic effect, meaning their combined action is more potent than either drug used alone.

The primary use of trimethoprim, particularly in its combination with sulfamethoxazole, is to treat a variety of bacterial infections. These include urinary tract infections, respiratory tract infections such as bronchitis and pneumonia, and certain types of gastrointestinal infections. It is also employed for the treatment and prevention of Pneumocystis jirovecii pneumonia, a serious opportunistic infection that can affect individuals with weakened immune systems. Trimetriprim is available in various dosage forms, including oral tablets and suspensions, and intravenous solutions. Its effectiveness and relatively low cost have made it a widely used antibiotic globally. However, like all antibiotics, the overuse and misuse of trimethoprim can contribute to the development of antibiotic resistance.