Last reviewed · How we verify

Cotrimoxazole prophylaxis

Institute of Tropical Medicine, Belgium · Phase 3 active Small molecule

Cotrimoxazole (trimethoprim-sulfamethoxazole) is a fixed-dose combination antibiotic that inhibits bacterial folate synthesis, preventing DNA replication in susceptible microorganisms.

Cotrimoxazole (trimethoprim-sulfamethoxazole) is a fixed-dose combination antibiotic that inhibits bacterial folate synthesis, preventing DNA replication in susceptible microorganisms. Used for Prophylaxis of Pneumocystis jirovecii pneumonia (PCP) in immunocompromised patients, Prophylaxis of toxoplasmosis in HIV-positive patients with CD4 count <100 cells/μL, Prophylaxis of other opportunistic infections in immunocompromised populations.

At a glance

Generic nameCotrimoxazole prophylaxis
Also known asCTX, Bacrtim (R), Trimethoprim-Sulfamethoxazole Combination
SponsorInstitute of Tropical Medicine, Belgium
Drug classAntibiotic combination (sulfonamide + diaminopyrimidine)
TargetDihydrofolate reductase and dihydropteroate synthase
ModalitySmall molecule
Therapeutic areaInfectious Disease
PhasePhase 3

Mechanism of action

Trimethoprim inhibits dihydrofolate reductase while sulfamethoxazole inhibits dihydropteroate synthase, both enzymes critical for bacterial folate metabolism. This dual mechanism provides synergistic bactericidal activity against a broad spectrum of gram-positive and gram-negative bacteria, as well as certain parasites and fungi. Prophylactic use prevents opportunistic infections in immunocompromised patients.

Approved indications

Common side effects

Key clinical trials

Primary sources

Every claim on this page is sourced from regulatory or scientific primary sources. See our editorial policy for full methodology.

SourceUsed for
ClinicalTrials.govTrial enrolment, design, endpoints, results