Pimobendan (or pimobendane)(INN) is a veterinary medication manufactured by Boehringer Ingelheim under the trade names Vetmedin and Acardi (Japan). It is both a calcium sensitizer and a selective inhibitor of phosphodiesterase III (PDE3) with positive inotropic and vasodilator effects.

Pimobendan is used in the management of heart failure in dogs, most commonly caused by myxomatous mitral valve disease (also previously known as endocardiosis), or dilated cardiomyopathy.  Research has shown that pimobendan increases survival time and improves quality of life in canine patients with congestive heart failure secondary to mitral valve disease when compared with benazepril, an angiotensin-converting-enzyme (ACE) inhibitor.  Under the trade name Acardi, it is available for human use in Japan.

Mechanism of action

Pimobendan is a positive inotrope (increases myocardial contractility). It sensitizes and increases the binding efficiency of cardiac troponin in the myofibril to the calcium ions that are already present in systole. In normal hearts it increases the consumption of oxygen and energy to the same degree as dobutamine but in diseased hearts it may not.  Pimobendan also causes peripheral vasodilation by inhibiting the function of phosphodiesterase III. This results in decreased resistance to blood flow through systemic arterioles, which decreases afterload (decreases the failing heart’s workload) and reduces the amount of mitral regurgitation.

Information from Wikipedia.com: https://en.wikipedia.org/wiki/Pimobendan