Inamrinone
Inamrinone (formerly known as amrinone) is a **bipyridine positive inotropic agent** and vasodilator (often referred to as an inodilator). - **Second-line agent** for the short-term management of congestive heart failure (CHF). - Structurally unrelated to cardiac glycosides or catecholamines. - Very expensive and requires intensive monitoring in a hospital setting. > **Clinical Pearl:** The drug's name was officially changed from amrinone to inamrinone to prevent potentially fatal medication errors caused by confusion with the antiarrhythmic drug *amiodarone*.
Mecanismo: Inamrinone acts primarily as a **phosphodiesterase III (PDE3) inhibitor**. - **Inhibition of PDE3** → decreased breakdown of intracellular cyclic AMP (cAMP) → increased intracellular calcium in the myocardium → **positive inotropy** (direct stimulation of cardiac contractility). - In vascular smooth muscle, increased cAMP leads to relaxation → **vasodilation**, which effectively reduces both cardiac preload and afterload.
Dosificación por especie
- Positive inotropic agent · 1-3 mg/kg IV followed by 30-100 micro-grams/kg/min IV infusion · IV · CRI
- Positive inotropic agent · 1-3 mg/kg IV as a slow IV bolus followed by a 10-100 micrograms/kg/min IV CRI; ½ the initial bolus may be administered 20-30 minutes after the first bolus. · IV · CRI
- Positive inotropic agent · 1-3 mg/kg IV as a slow IV bolus followed by a 10-100 micrograms/kg/min IV CRI; ½ the initial bolus may be administered 20-30 minutes after the first bolus. · IV · CRI
- Positive inotropic agent · 1-3 mg/kg IV followed by a 30-100 micrograms/kg/min IV CRI · IV · CRI
- Positive inotropic agent · 2 mg/kg bolus IV , followed by 30-300 micrograms/kg/min IV infusion · IV · CRI
- For patients coming off cardiopulmonary bypass with poor cardiac contractility · 0.25-0.6 mg/kg loading, then 5-45 micrograms/kg/min CRI · IV · CRI
- Adjunctive treatment for calcium channel blocker overdose · 30-100 micrograms/kg/min CRI. · IV · CRI · Alternative to dopamine or dobutamine; used with fluids, IV calcium, and potentially glucagon.
Las dosis son una referencia clínica para veterinarios colegiados. Confirme siempre con la ficha técnica vigente y el paciente individual.
Vías de administración
Contraindicaciones
- Severe aortic or pulmonic valve disease
- Hypersensitivity to inamrinone or bisulfites
Efectos adversos
- Arrhythmias
- Hypotension
- Vomiting
- Diarrhea
- Thrombocytopenia (particularly with prolonged therapy)
- Hepatotoxicity
- Hypersensitivity reactions (variable symptomatology: pericarditis to myositis)
Interacciones farmacológicas
- Digoxin · Additive inotropic effect; generally considered a positive drug interaction.
- Disopyramide · May cause excessive hypotension when used concurrently.
Monitorización
- Blood pressure
- Heart rate/rhythm (continuous ECG recommended)
- Body weight
- Platelet counts
Sobredosis
Because **hypotension** is the primary problem that would generally be seen, circulatory support should be instituted immediately. Only one human case of accidental massive overdose resulting in death has been reported (causal relationship not unequivocally established).
La referencia de fármacos de VetSheet está destinada a veterinarios colegiados como apoyo a la decisión clínica, no sustituye el juicio profesional ni la ficha técnica vigente del fabricante.