Trimethoprim: Uses, Mechanism, Side Effects

Trimethoprim: a targeted antibiotic for UTIs and prostatitis that inhibits bacterial dihydrofolate reductase for rapid bacterial growth suppression. In this concise video you’ll learn how trimethoprim works at the molecular level, why it’s often paired with sulfamethoxazole for co-trimoxazole synergy, and which infections it reliably treats—especially uncomplicated cystitis, recurrent UTI prophylaxis and chronic prostatitis due to excellent prostatic and urinary penetration.

The video explains pharmacokinetics (oral absorption, broad tissue distribution including urine, sputum, prostatic fluid and partial CSF penetration, renal elimination, and an 8–15 hour half-life) and practical dosing considerations in renal impairment. You’ll also get a clear breakdown of resistance mechanisms—enzyme modification, plasmid-acquired resistant DHFR, efflux pumps and permeability changes—and learn which pathogens are unaffected (Pseudomonas, Bacteroides, anaerobes, atypicals).

Safety and interactions are covered plainly: avoid in early pregnancy and megaloblastic anemia, watch for hyperkalemia and raised serum creatinine (due to reduced tubular secretion rather than true renal failure), and avoid combining with methotrexate or other drugs that increase hyperkalemia risk or potentiate anticoagulation. Practical clinical takeaways include when trimethoprim is appropriate, monitoring tips, and how to manage common side effects.

Watch to gain a compact, clinically focused understanding of trimethoprim’s mechanism, uses, risks and monitoring—essential viewing for clinicians, pharmacists and students prescribing or managing common urinary and prostatic infections.