Used primarily in the treatment and prevention of malaria, particularly in combination with proguanil. This combination is effective against Plasmodium falciparum, including chloroquine-resistant strains. It is commonly prescribed for travelers to malaria-endemic regions due to its high efficacy and favorable safety profile. Also used in the management of Pneumocystis jirovecii pneumonia (PCP), especially in immunocompromised patients such as those with HIV/AIDS who cannot tolerate sulfonamide-based therapies. Its mechanism involves inhibition of mitochondrial electron transport in protozoal parasites, disrupting energy production and leading to parasite death. Available in oral tablet and suspension forms, it offers a convenient dosing regimen with minimal side effects, making it suitable for both prophylaxis and treatment in adults and children.