Sulfamethoxazole sodium is widely used in the treatment of bacterial infections, particularly in combination with trimethoprim. This combination is effective against a variety of infections, including urinary tract infections, respiratory tract infections, and gastrointestinal infections. It is also used in the treatment of certain types of pneumonia, especially Pneumocystis pneumonia, which is common in immunocompromised patients such as those with HIV/AIDS. Additionally, it is employed in the prophylaxis of infections in individuals undergoing certain medical treatments or surgeries. Its broad-spectrum antibacterial properties make it a valuable component in both therapeutic and preventive medical applications.