An inotrope is an agent which increases or decreases the force or energy of muscular contractions. Negatively inotropic (in·o·trop·ic) (in²o-trop¢ik) [ino- + -tropic] agents weaken the force of muscular contraction. Positively inotropic agents increase the strength of muscular contraction.

The term is often used in reference to the way various drugs affect the strength of contraction of heart muscle (myocardial contractility).