rifampicin + trimethoprim

**Rifampicin + trimethoprim** is an oral fixed-dose antibacterial combination historically marketed as **Rifaprim**. Rifampicin inhibits bacterial DNA-dependent RNA polymerase through the beta subunit, blocking transcription, while trimethoprim competitively inhibits bacterial dihydrofolate reductase and depletes tetrahydrofolate required for nucleotide synthesis. The combination was developed to improve antibacterial activity and, particularly, to reduce selection of rifampicin-resistant urinary pathogens compared with rifampicin monotherapy. It was studied for recurrent or chronic urinary tract infections and chronic bacterial prostatitis, including infections associated with *Staphylococcus aureus*. Historical Rifaprim regimens included rifampicin 600 mg plus trimethoprim 160 mg once daily, while another urinary-infection regimen used 300 mg rifampicin plus 80 mg trimethoprim in the morning and twice those doses at night. ([pubmed.ncbi.nlm.nih.gov](https://pubmed.ncbi.nlm.nih.gov/383553/))

Brand names

Rifaprim

Other names

RIF-TMPrifampicin + trimethoprimrifampicin-trimethoprimrifampicin/trimethoprimrifampin + trimethoprimrifampin-trimethoprimTMP-RAMtrimethoprim + rifampicintrimethoprim + rifampintrimethoprim-rifampin