Gentamicin drug molecule. Ball-and-stick molecular model of gentamicin, an aminoglycoside antibiotic. It is used to treat a wide range of bacterial infections, such as endocarditis, meningitis, pneumonia, and urinary tract infections (UTIs), among several others. Its chemical formula is C21H43N5O7. Atoms are represented as spheres with conventional colour coding: hydrogen (white), carbon (black), oxygen (red), and nitrogen (blue).