Inamrinone
Inamrinone lactate
Also known as: Inocor · Amcoral · Vesistol · Wincoram · Amrinone lactate · Win-40680
Reviewed by the VetSheet Veterinary TeamUpdated Apr 5, 2026Evidence-based veterinary reference
This is a rate-based continuous infusion (CRI) dose. Calculate the infusion rate; do not use simple weight scaling.
Doses are a clinical reference for licensed veterinary professionals. Always confirm against the current label and the individual patient.
Dosing by species
🌎 NA — North America🌍 EU — Europe
Dogs
| Indication | Dose | Route | Frequency | Duration | Region |
|---|---|---|---|---|---|
| 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 | — | 🌎 NA |
| Positive inotropic agent | 1-3 mg/kg IV followed by a 30-100 micrograms/kg/min IV CRI | IV | CRI | — | 🌎 NA |
| Positive inotropic agent | 2 mg/kg bolus IV , followed by 30-300 micrograms/kg/min IV infusion | IV | CRI | — | 🌎 NA |
| 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 | — | 🌎 NA |
| Adjunctive treatment for calcium channel blocker overdose | 30-100 micrograms/kg/min CRI. | IV | CRI | — | 🌎 NA |
- Adjunctive treatment for calcium channel blocker overdose: Alternative to dopamine or dobutamine; used with fluids, IV calcium, and potentially glucagon.
Cats
| Indication | Dose | Route | Frequency | Duration | Region |
|---|---|---|---|---|---|
| Positive inotropic agent | 1-3 mg/kg IV followed by 30-100 micro-grams/kg/min IV infusion | IV | CRI | — | 🌎 NA |
| 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 | — | 🌎 NA |
Doses are a clinical reference for licensed veterinary professionals. Always confirm against the current label and the individual patient.
Overview
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.
Mechanism of action
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.
Safety & warnings
Contraindications
- Severe aortic or pulmonic valve disease
- Hypersensitivity to inamrinone or bisulfites
Adverse effects
- Arrhythmias
- Hypotension
- Vomiting
- Diarrhea
- Thrombocytopenia (particularly with prolonged therapy)
- Hepatotoxicity
- Hypersensitivity reactions (variable symptomatology: pericarditis to myositis)
Precautions
Contraindicated in severe aortic or pulmonic valve disease. Use extreme caution in patients with hypertrophic cardiomyopathy. Reproductive safety data are conflicting (FDA Category C); use only when benefits outweigh risks. It is unknown if it is secreted in milk; exercise caution. Must only be used in settings where appropriate cardiovascular monitoring can be employed.
Drug interactions
Additive inotropic effect; generally considered a positive drug interaction.
May cause excessive hypotension when used concurrently.
Monitoring
- Blood pressure
- Heart rate/rhythm (continuous ECG recommended)
- Body weight
- Platelet counts
Pharmacokinetics
Absorption
Rapidly absorbed after oral administration, though no oral commercial dosage forms are available. After initial IV injection, effects begin within 2-3 minutes and peak within 10 minutes.
Distribution
Apparent volume of distribution is 1.2 L/kg (in humans). Exhibits low to moderate protein binding (10-49%). Unknown if it crosses the placenta, blood-brain barrier, or enters maternal milk.
Metabolism
Not extensively described in the monograph.
Elimination
Eliminated primarily via the kidneys. About 63% of a dose is excreted (10-40% unchanged) into the urine. Duration of effect is dose-related (30 minutes to 2 hours in humans).
Overdose
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).
Available products
Formulations
- Injection
Human-labeled
- Inamrinone Lactate for Injection: 5 mg/mL (as lactate) in 20 mL ampules
Regulatory status
No regulatory data for: 🇺🇸 US · 🇪🇺 EU · 🇬🇧 UK · 🇭🇰 HK · 🇹🇼 TW · 🇯🇵 JP · 🇰🇷 KR · 🇦🇺 AU
Storage & stability
Store at room temperature and protect from light. Stable for 2 years after manufacture. Compatible with 0.45% or 0.9% sodium chloride injection. Incompatible with solutions containing dextrose or sodium bicarbonate.
Client information
- Hospital Use Only: This medication is administered intravenously in a hospital setting where intensive care is available.
- Investigational Nature: Clients should be made aware of the 'investigational nature' (off-label use) of this drug in dogs and cats.
- Intensive Monitoring: Your pet will require continuous monitoring of their heart rhythm (ECG) and blood pressure while receiving this medication.
VetSheet drug reference is intended for licensed veterinary professionals as a clinical decision-support aid, not a substitute for professional judgement or the manufacturer’s current label.