Milrinone

What milrinone is and how it works

Milrinone is an intravenous medicine that helps the heart pump more effectively (a positive inotrope) and widens blood vessels (a vasodilator). It is given only in a hospital or acute-care setting, always under continuous heart monitoring, for short-term treatment of severe, acute heart failure or low-output states. (1) (2)

Milrinone carries a genuine, serious safety warning: it has not been shown to be safe or effective for more than 48 hours of use, and its use is linked to an increased chance of abnormal heart rhythms (ventricular arrhythmias), including some that can be life-threatening. This is why it is only ever given in a monitored hospital setting with continuous heart-rhythm (ECG) tracing, for a short, defined course of treatment decided by your care team -- it is never a medicine you take yourself at home.

Mechanism of action: how milrinone works

Milrinone is a selective inhibitor of the peak III cyclic-AMP phosphodiesterase (PDE3) isoenzyme in cardiac and vascular smooth muscle, increasing intracellular cyclic AMP and producing positive inotropic (stronger heart contraction) and vasodilator effects with little chronotropic (heart-rate) activity, and also improving left ventricular diastolic relaxation. (1) (2)

What milrinone is used for

Before taking milrinone

Do not take / not appropriate for

• Milrinone must not be given to anyone with a known hypersensitivity (allergic reaction) to it. (all countries) (1) (2)
• Milrinone must not be given to patients with severe hypovolaemia (severely reduced blood volume) until this is corrected. (United Kingdom, European Union) (2)

Tell your clinician about

• This section is intended for the clinical team managing an inpatient, monitored infusion, not for patient self-management -- milrinone is never self-administered.
• Any history of abnormal heart rhythms (arrhythmias), especially ventricular arrhythmias.
• Any electrolyte abnormalities, especially low blood potassium (hypokalaemia), which increases arrhythmia risk.
• Whether the patient is taking digoxin (digitalis) -- levels and effects need to be considered alongside milrinone.
• Kidney function, since the maintenance infusion rate depends on it.

How to take milrinone

• Given only by intravenous injection/infusion in a hospital or closely monitored acute-care setting -- never self-administered.
• Continuous ECG (heart rhythm) monitoring is required throughout the infusion, along with regular blood pressure, heart rate, fluid balance, electrolyte, and kidney-function checks.
• Not given for longer than the short course (typically 48-72 hours for heart failure, or up to about 12 hours post-cardiac-surgery per the UK source reviewed) that the care team intends -- safety and effectiveness beyond 48 hours have not been shown.

Procedures and treatment changes

Tell the treating team before surgery, procedures, or any medicine change. Do not alter treatment without the responsible clinician. (1) (2) (3) (4) (5) (6)

Missed dose

Not applicable in the usual sense -- milrinone is given as a continuous, clinician-managed hospital infusion, so a 'missed dose' is a clinical monitoring matter for the care team, not something a patient manages.

Overdose

Because milrinone is administered and continuously monitored by a healthcare team in a hospital setting, any concern about an incorrect dose or rate is identified and managed directly by that team, typically by reducing or stopping the infusion and providing supportive care, including management of any resulting arrhythmia or hypotension. (1)

Side effects

Side effects and their urgency vary; report severe, persistent, or concerning symptoms.

Serious warnings

Interactions

• Furosemide (and bumetanide): forms a precipitate if mixed directly with milrinone in the same IV line -- these must not be co-administered through the same line. (1) (2)
• Sodium bicarbonate: should be avoided as a diluent for milrinone, per the UK source reviewed. (2)
• Digoxin (digitalis): milrinone can be used in digitalised patients without additional toxicity in the sources reviewed, but abnormal digoxin levels are noted as a risk factor for arrhythmia when combined with milrinone. (1) (2)
• No other significant interactions were identified in the US source reviewed with antiarrhythmics, other vasodilators, diuretics generally, or anticoagulants. (1)

Pregnancy, breastfeeding, kidney/liver function, age

Monitoring

Before starting

• Baseline ECG and cardiac rhythm assessment
• Baseline blood pressure and heart rate
• Baseline electrolytes (especially potassium) and renal function
• Correction of hypovolaemia before starting, where present

During treatment

• Continuous ECG monitoring throughout the infusion, in a setting equipped for immediate management of ventricular arrhythmias.
• Regular blood pressure and heart rate monitoring, with infusion-rate reduction if hypotension develops.
• Regular electrolyte monitoring, correcting hypokalaemia promptly.
• Regular renal function (serum creatinine) monitoring, with infusion-rate adjustment as needed.
• Infusion-site monitoring for local reactions.

Storage

Stored and prepared by hospital pharmacy/clinical staff according to the product's specific storage and dilution requirements; not self-stored by patients at home.

Frequently asked questions

References

1. MILRINONE LACTATE injection, solution -- full prescribing informationDailyMed (U.S. National Library of Medicine) -- FDA-approved drug labeling · United States · accessed 2026-07-30 · source 1
2. Milrinone 1mg/ml Solution for Injection and Infusion -- Summary of Product Characteristics (SmPC)electronic medicines compendium (emc), United Kingdom -- Wockhardt UK Ltd · United Kingdom · accessed 2026-07-30 · source 2
3. Milrinone 1 mg/ml Solution for Injection/Infusion -- HPRA Ireland product documentsHealth Products Regulatory Authority (HPRA), Ireland -- national marketing authorisation · European Union (Ireland, as a directly confirmed EU member state) · accessed 2026-07-30 · source 3
4. PRIMACOR Injection (milrinone lactate) and generic Milrinone Lactate Injection -- Health Canada Product MonographsHealth Canada -- Product Monograph · Canada · accessed 2026-07-30 · source 4
5. Milrinone GH concentrate for infusion -- AUST R 204795 (Generic Health Pty Ltd); PRIMACOR (Sanofi-Aventis Australia, ARTG 10372) cancelled by sponsor December 2023Therapeutic Goods Administration (TGA), Australia -- Australian Register of Therapeutic Goods (ARTG) · Australia · accessed 2026-07-30 · source 5
6. MILRINONE-BAXTER (milrinone) -- New Zealand Data Sheet, dated 8 January 2026Medsafe (New Zealand regulator) -- New Zealand Data Sheet · New Zealand · accessed 2026-07-30 · source 6

Brand names by country

Single-ingredient milrinone names are shown separately by country. Product availability, strengths, and supply rules can change; combination products are not included here.

Priority countries