Milrinone (Primacor)

Last updated 12/03/18

Definition

• Inotrope and vasodilator used as infusion used as short terma management of severe heart failure

Features

• Phosphodiesterase inhibitor
• Does not effect adrenoreceptors
• Effective in patients on beta blockers with beta-adrenoreceptor down regulation
• Used as a titratable infusion
• Minimal metabolsim
• T/2 2hrs

Mechanism

• Inhibitor of cAMP phosphodiesterase: increases cAMP
• Inotrope
• Vascular and bronchial muscle relaxation
• Pulmonary and systemic arterial and venous dilation
• Inodilator: improves diastolic function

Indications

• Low cardiac output states
• Severe Congestive Cardiac Failure (CCF) not responsive to other therapies
• Low cardiac output after cardiac surgery

Dose

• IV only
• Ampule 10mg in 10ml = 1mg/ml
• Infusion
• Loading dose 50mcg/kg bolus over 10 minutes
• Maintenance 0.375-0.750mcg/kg/min
• 10mg to 50ml with normal saline = 200mcg/mL
• Should be given via a dedicated lumen, preferably via Central Venous Catheter (CVC)
• Not usually given for more than 48hrs
• Reduce rate in renal impairment

Side Effects/Precuations/Contraindications

• Side Effects
• Hypotension
• Consider fluids
• May be combined with Noradrenaline
• Tachycardia, arrythmias
• Infusions require ECG monitoring
• Headache
• Tremor
• Thrombocytopaenia
• Deranged LFTs
• Precautions
• Recent Acute Myocardial Infarction (AMI) may exacerbate ischaemia
• Atrial Fibrillation (AF), Atrial Flutter: may increase ventricular response rate
• Contraindications
• Severe aortic stenosis (AS) or pulmonary stenosis
• Previous reaction

---

References

1. Health South Western Sydney: Drug Guideline Title: Milrinone. March 2015.
2. Life in the Fast Lane: Milrinone. 21/04/2013
3. AMH: Milrinone. January 2018.