Пимобендан

Описание

Pimobendan, a novel cardiotonic vasodilator, was introduced in Japan for the treatment of acute and mild to moderate chronic heart failure. It is a phosphodiesterase Ⅲ inhibitor and is able to enhance sensitization of myocardial contractile regulatory protein to calcium ions. The combination of these effects contribute to its inotropic activity. In patients with severe congestive heart failure, orally administered pimobendan improves cardiac index, stroke volume index, pulmonary wedge pressure, and systemic and pulmonary vascular resistance. Pimobendan is reported to be well tolerated and largely devoid of the proarrhythmic effects of classical phosphodiesterase Ill inhibitors. Studies also suggested that combination of the inotropic agent pimobendan with an ACE inhibitor such as enalapril may be superior to monotherapy for heart failure patients.

Химические свойства

White Solid

Использование

Pimobendan is a cardiotonic agent. The study of the cardiotonic mechanism of Pimobendan using ventricular muscles from rabbits and guinea pigs suggests that Pimobendan acts by inhibiting phosphodiesterase III and potassium channel. The potent venodilating action of Pimobendan makes it a suitable treatment option for patients with congestive heart failure (CHF) as it also improves systemic vasoconstriction.

Определение

ChEBI: Pimobendan is a pyridazinone and a member of benzimidazoles. It has a role as a cardiotonic drug, a vasodilator agent and an EC 3.1.4.* (phosphoric diester hydrolase) inhibitor.

Биологическая активность

Pimobendan is an inhibitor of phosphodiesterase 3 (PDE3; IC50 = 0.32 μM for guinea pig cardiac enzyme) that is selective for PDE3 over PDE1, PDE2, and PDE4 (IC50s = >30 μM). It is also a calcium sensitizer, decreasing the concentration of calcium required for half-maximal contractile force in isolated, skinned porcine ventricular fibers. Pimobendan increases the force of contraction in electrically-stimulated isolated guinea pig papillary muscles with an EC50 value of 6 μM, indicating positive inotropic effects. It increases survival time in dogs with congestive heart failure due to myxomatous mitral valve disease when administered in combination with angiotensin-converting enzyme inhibitors and furosemide . Formulations containing pimobendan have been used in the treatment of heart failure in dogs.

Механизм действия

The mechanism of mild mitral regurgitation (MR) in dogs treated with Pimobendan is a dual mechanism of action, which enhances myocardial contractility by increasing calcium sensitisation of troponin C and promotes vasodilatation by inhibiting PDEIII.

Побочные эффекты

The most common side effects include gastrointestinal effects such as decreased appetite, and diarrhea. Other possible side effects include lethargy and difficulty breathing This short-acting medication should stop working within 24 hours, although effects can be longer in pets with liver or kidney disease.