[Durgical](https://durgical.com/en/) › [DurgiPedia](https://durgical.com/en/durgipedia/) › [Pharmacology](https://durgical.com/en/pharmacology/) › [Vasopressors and inotropes](https://durgical.com/en/pharmacology/classes/vasopressors-and-inotropes/) › Milrinone [Pharmacology](https://durgical.com/en/pharmacology/) · [Vasopressors and inotropes](https://durgical.com/en/pharmacology/classes/vasopressors-and-inotropes/) # Milrinone An intravenous inodilator that blocks phosphodiesterase 3: it strengthens the heartbeat and widens vessels in acute decompensated heart failure. Updated 2026-11-01 - Class: [Vasopressors and inotropes](https://durgical.com/en/pharmacology/classes/vasopressors-and-inotropes/) - Enzyme: Phosphodiesterase 3 (PDE3) - ATC code: C01CE02 ## ⚠ High-alert medication An error with this medicine can cause serious harm: double checks and protocols are used. ✂**Phosphodiesterase 3 (PDE3)**Milrinone ⓘ No structure of milrinone bound to PDE3 is available; the figure shows trequinsin, another PDE3 inhibitor, in the catalytic site of human PDE3A. **Target in 3D:** Phosphodiesterase 3 (PDE3). PDB structure 7L28 (RCSB PDB, public domain). [View the structure at RCSB PDB](https://www.rcsb.org/structure/7L28) · Drag to rotate · pinch to zoom ## Mechanism of action Milrinone, a bipyridine, selectively inhibits phosphodiesterase 3 in heart and vascular muscle. cAMP is broken down more slowly: in myocytes, more calcium enters and contraction strengthens; in vascular smooth muscle, cAMP causes relaxation. Because it bypasses beta receptors, it still works in patients on beta blockers. - Milrinone inhibits phosphodiesterase 3 - cAMP is broken down more slowly - Heart: more calcium entry, stronger contraction - Vessels: relaxation, lower preload and afterload ## Pharmacokinetics **Distribution** Small volume of distribution **Elimination** Mainly by the kidneys as unchanged drug; elimination slows markedly in kidney impairment **Half-life** Mean terminal half-life about 2.3 hours in heart failure (label) ## Indications - Short-term intravenous treatment of acute decompensated heart failure [Heart failure →](https://durgical.com/en/conditions/heart-failure/) ## Adverse effects ### Common - Hypotension - Headache - Angina and chest pain - Hypokalaemia - Tremor ### Serious (rare, important) - Ventricular arrhythmias, including ventricular tachycardia - Supraventricular arrhythmias; faster ventricular response in atrial fibrillation or flutter - Thrombocytopenia ## Contraindications - Hypersensitivity to milrinone - Severe obstructive aortic or pulmonic valve disease in place of surgical relief (not recommended) ## Key interactions **Furosemide injected into the same line** Immediate precipitate: not given through the milrinone line **Diuretics** Better cardiac output can increase diuresis; potassium and fluid balance need watching ## What is monitored - Continuous ECG - Blood pressure and heart rate - Potassium and other electrolytes - Kidney function and urine output - Platelet count ## Administration and safety - Intravenous infusion by pump, often after a loading dose; in a monitored setting. - Do not inject furosemide into the milrinone line: they form a precipitate. - The rate is reduced in kidney impairment; the prescriber adjusts it to creatinine clearance. - Check the infusion site; avoid extravasation. ## Nursing care - Before: correct low potassium; check kidney function. - During: continuous ECG; report new arrhythmias, chest pain or a fall in blood pressure. - Check potassium, fluid balance and urine output, as diuresis may increase. - If blood pressure falls too much, the infusion is slowed or stopped as instructed. ## Pregnancy and breastfeeding Human data are limited; it is used when the maternal circulation needs support. ## Memory aid MILrinone: More cAMP, Inodilator, Lose it through the kidneys (adjust in renal failure). ## Test yourself Think of the answer, then tap the question to see it. ## How does milrinone raise contractility? By inhibiting phosphodiesterase 3, cAMP is broken down more slowly, so more calcium enters the myocyte and contraction strengthens. ## Why can milrinone work in a patient on a beta blocker when dobutamine does not? Milrinone acts downstream of the beta receptor, at phosphodiesterase 3, so it does not need beta-receptor activation. ## Which common diuretic must not be injected into a milrinone line? Furosemide, which forms a precipitate with milrinone. ## Why is the milrinone infusion adjusted in kidney failure? It is eliminated mainly unchanged by the kidneys; in kidney impairment its elimination half-life increases markedly. [Add to my cards (4)](https://durgical.app/estudiar/?add=/en/pharmacology/milrinone/) ## Related drugs - [Dobutamine](https://durgical.com/en/pharmacology/dobutamine/) - [Levosimendan](https://durgical.com/en/pharmacology/levosimendan/) ## Related conditions - [Heart failure](https://durgical.com/en/conditions/heart-failure/) [← Back to the class: Vasopressors and inotropes](https://durgical.com/en/pharmacology/classes/vasopressors-and-inotropes/) Educational content on how drugs work; not a prescribing guide and no substitute for a health professional's advice. No doses are given. Sources: [DailyMed - MILRINONE LACTATE IN DEXTROSE injection, solution](https://dailymed.nlm.nih.gov/dailymed/drugInfo.cfm?setid=4c2f052b-7ba2-4122-a50b-37ef2a834d61) (DailyMed (U.S. National Library of Medicine), 2026); [ATCDDD - ATC/DDD Index](https://atcddd.fhi.no/atc_ddd_index/?code=C01CE02) (WHO Collaborating Centre for Drug Statistics Methodology, 2026); Farmacología básica y clínica (Katzung), cap. 13 (McGraw Hill, 2025). ## **Spotted a mistake?** We are always improving for the community. Tell us what is wrong and our team will review it. Report a mistake Representative model, for educational purposes only. --- Source: https://durgical.com/en/pharmacology/milrinone/ License: CC BY 4.0 (https://creativecommons.org/licenses/by/4.0/). Cite as: DurgiPedia (durgical.com), https://durgical.com/en/pharmacology/milrinone/