Drugs & Medication

An inotrope (IPA: [ˈaɪnətrop]) is an agent which increases or decreases the force or energy of muscular contractions. Negatively inotropic agents weaken the force of muscular contractions. Positively inotropic agents increase the strength of muscular contraction.

Most commonly, the term is used in reference to various drugs that affect the strength of contraction of heart muscle (myocardial contractility). Both positive and negative inotropes are used in the management of various cardiovascular conditions. The choice of agent largely depends on specific pharmacological effects of individual agents with respect to the condition.

Positive inotropic agents

Positive inotropic agents increase myocardial contractility, and are used to support cardiac function in conditions such as decompensated congestive heart failure, cardiogenic shock, septic shock, myocardial infarction, cardiomyopathy, etc.

Examples of positive inotropic agents include:

• Calcium sensitisers
  • Levosimendan
• Cardiac glycosides
  • Digoxin
• Catecholamines
  • Dopamine
  • Dobutamine
  • Dopexamine
  • Epinephrine (adrenaline)
  • Isoprenaline (isoproterenol)
  • Norepinephrine (noradrenaline)

Negative inotropic agents

Negative inotropic agents decrease myocardial contractility, and are used to decrease cardiac workload in conditions such as angina. While negative inotropism may precipitate or exacerbate heart failure, certain beta blockers (e.g. carvedilol) have been shown to reduce morbidity and mortality in congestive heart failure.

• Beta blockers
• Diltiazem
• Verapamil