Trimethoprim-sulfamethoxazole
Related Experiment Video
Updated: Oct 19, 2026

Quadruple-Checkerboard: A Modification of the Three-Dimensional Checkerboard for Studying Drug Combinations
Published on: July 24, 2021
1Division of Infectious Diseases, Mayo Clinic Scottsdale, Arizona.
Abstract:
After 25 years of use in the United States, trimethoprim-sulfamethoxazole (TMP-SMX) is widely prescribed for various indications. By virtue of sequential blockade of microbial folic acid synthesis, the antimicrobial combination has excellent in vitro inhibitory activity against many common respiratory and urinary tract pathogens, as well as many nosocomial infecting strains. In patients infected with the human immunodeficiency virus, TMP-SMX provides prophylactic and therapeutic potency against Pneumocystis carinii but at the risk of frequent side effects. TMP-SMX is also used for treatment of pulmonary and disseminated nocardiosis and some forms of Wegener's granulomatosis, as well as for prophylaxis of spontaneous bacterial peritonitis. Increasing bacterial resistance and concern about occasional severe adverse effects suggest that the usefulness of TMP-SMX may diminish in the future.
Related Concept Videos
Combined Effects of Drugs: Synergism
Such synergistic combinations...
Anthelminthic Agents
Urinary Tract Infection III: Diagnostic Studies and Interprofessional Care
Antiprotozoal Agents
Pulmonary Tuberculosis V
Latent tuberculosis infection occurs when TB bacteria are present in a person's body, but are not causing illness or symptoms. It is not contagious, and preventive treatment is crucial to avoid the progression...
Inhibitors of Bacterial DNA Synthesis
