MILRINONE LACTATE IN DEXTROSE 5%
Clinical safety rating: safe
No significant drug interactions Can cause ventricular arrhythmias and hypotension.
Milrinone is a phosphodiesterase III (PDE3) inhibitor that increases intracellular cyclic adenosine monophosphate (cAMP) in cardiac and vascular smooth muscle, leading to positive inotropy and vasodilation.
| Metabolism | Hepatic metabolism via conjugation (glucuronidation and sulfation) with minimal CYP450 involvement; approximately 85% of the drug is excreted unchanged in urine. |
| Excretion | Primarily renal (85% as unchanged drug); minor biliary/fecal (<5%). |
| Half-life | Terminal elimination half-life: 2.3–2.7 hours in normal renal function; prolonged to 3–4 hours in heart failure; up to 8–10 hours in severe renal impairment (creatinine clearance <30 mL/min). |
| Protein binding | Approximately 70% bound to plasma proteins (mainly albumin). |
| Volume of Distribution | 0.38–0.54 L/kg; increased in heart failure (up to 0.6 L/kg), indicating distribution into extravascular tissues. |
| Bioavailability | Not applicable (administered intravenously only); oral bioavailability is low (~0–5%) due to extensive first-pass metabolism, not used clinically. |
| Onset of Action | Intravenous: 5–15 minutes (bolus); within 30 minutes (continuous infusion). |
| Duration of Action | Hemodynamic effects persist for approximately 2–4 hours after discontinuation of infusion; may persist longer in renal impairment. |
IV loading dose: 50 mcg/kg over 10 minutes, followed by continuous IV infusion of 0.375-0.75 mcg/kg/min. Titrate based on hemodynamic response. Maximum infusion rate: 1.13 mg/kg/day.
| Dosage form | INJECTABLE |
| Renal impairment | Creatinine clearance (CrCl) 10-50 mL/min: reduce infusion rate by 50%. CrCl <10 mL/min: reduce infusion rate by 75%. |
| Liver impairment | No specific dose adjustments recommended for hepatic impairment. Use caution in severe hepatic dysfunction (Child-Pugh class C) due to limited data. |
| Pediatric use | Loading dose: 50-75 mcg/kg IV over 10-15 minutes, followed by continuous infusion of 0.5-0.75 mcg/kg/min. Titrate to clinical response. Maximum infusion rate: 1.13 mg/kg/day. |
| Geriatric use | No specific dose adjustments; however, elderly patients may have reduced renal function. Adjust dose based on creatinine clearance as per renal adjustment guidelines. |
| 1st trimester | Consult provider |
| 2nd trimester | Consult provider |
| 3rd trimester | Consult provider |
Clinical note
No significant drug interactions Can cause ventricular arrhythmias and hypotension.
| FDA category | Animal |
| Breastfeeding | Not known whether milrinone is excreted in human milk. Caution should be exercised when administered to a nursing woman. M/P ratio not determined. |
| Teratogenic Risk | Pregnancy Category C. Milrinone crosses the placenta. Animal studies have shown no teratogenic effects; however, adequate studies in pregnant women are lacking. Use only if potential benefit justifies potential risk to the fetus. |
■ FDA Black Box Warning
None specified in FDA labeling; however, use may be associated with increased mortality in long-term studies of heart failure patients.
| Common Effects | Arrhythmias |
| Serious Effects |
Hypersensitivity to milrinone or any formulation component; severe aortic or pulmonic valvular disease (e.g., aortic stenosis); acute myocardial infarction.
| Precautions | Risk of hypotension, ventricular arrhythmias, and atrial fibrillation; monitor electrolytes and renal function; use caution in patients with renal impairment (dose adjustment required); may increase mortality with long-term use. |
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| Fetal Monitoring | Monitor maternal heart rate, blood pressure, ECG, fluid and electrolyte status, renal function, and platelet count. Fetal monitoring may include heart rate assessment if clinically indicated. |
| Fertility Effects | No adequate data on fertility effects in humans. Animal studies have not reported impaired fertility. |