Primacor IV

Medical Editor: John P. Cunha, DO, FACOEP Last updated on RxList: 10/12/2021
Primacor IV Side Effects Center

What Is Primacor?

Primacor (milrinone lactate) is a vasodilator used as a short-term treatment for treat life-threatening heart failure.

What Are Side Effects of Primacor?

Common side effects of Primacor include:

  • headache,
  • tremors, or
  • easy bruising or bleeding.

Tell your doctor if you have a serious side effect of Primacor including:

  • chest pain,
  • feeling like you might pass out,
  • bronchospasm (wheezing, chest tightness, trouble breathing), or
  • low potassium (confusion, uneven heart rate, extreme thirst, increased urination, leg discomfort, muscle weakness or limp feeling).

Dosage for Primacor

Primacor is given in a hospital setting under a physician's supervision. A loading (starting) dose of 50 mcg/kg is administered slowly over 10 minutes followed by a continuous infusion (maintenance dose) determined by the patient's weight.

What Drugs, Substances, or Supplements Interact with Primacor?

Primacor may interact with digoxin (digitalis, Lanoxin, Lanoxicaps), or diuretics (water pills). Other drugs may interact with Primacor. Tell your doctor all prescription and over-the-counter medications and supplements you use.

Primacor During Pregnancy or Breastfeeding

During pregnancy, Primacor should be used only if prescribed. It is not known whether this medication passes into breast milk or if it could harm a nursing baby. Consult your doctor before breastfeeding.

Additional Information

Our Primacor (milrinone lactate) Side Effects Drug Center provides a comprehensive view of available drug information on the potential side effects when taking this medication.

This is not a complete list of side effects and others may occur. Call your doctor for medical advice about side effects. You may report side effects to FDA at 1-800-FDA-1088.


See Images
Primacor IV Consumer Information

Get emergency medical help if you have signs of an allergic reaction: hives; difficult breathing; swelling of your face, lips, tongue, or throat.

Tell your caregivers at once if you have:

  • chest pain;
  • a light-headed feeling, like you might pass out; or
  • low potassium level--leg cramps, constipation, irregular heartbeats, fluttering in your chest, increased thirst or urination, numbness or tingling, muscle weakness or limp feeling.

Common side effects may include:

  • headache;
  • chest pain; or
  • dizziness.

This is not a complete list of side effects and others may occur. Call your doctor for medical advice about side effects. You may report side effects to FDA at 1-800-FDA-1088.

Read the entire detailed patient monograph for Primacor IV (Milrinone)


Heart Disease: Symptoms, Signs, and Causes See Slideshow
Primacor IV Professional Information


Cardiovascular Effects: In patients receiving PRIMACOR in Phase II and III clinical trials, ventricular arrhythmias were reported in 12.1%: Ventricular ectopic activity, 8.5%; nonsustained ventricular tachycardia, 2.8%; sustained ventricular tachycardia, 1% and ventricular fibrillation, 0.2% (2 patients experienced more than one type of arrhythmia). Holter recordings demonstrated that in some patients injection of PRIMACOR increased ventricular ectopy, including nonsustained ventricular tachycardia. Life-threatening arrhythmias were infrequent and when present have been associated with certain underlying factors such as preexisting arrhythmias, metabolic abnormalities (e.g. hypokalemia), abnormal digoxin levels and catheter insertion. PRIMACOR was not shown to be arrhythmogenic in an electrophysiology study. Supraventricular arrhythmias were reported in 3.8% of the patients receiving PRIMACOR. The incidence of both supraventricular and ventricular arrhythmias has not been related to the dose or plasma milrinone concentration.

Other cardiovascular adverse reactions include hypotension, 2.9% and angina/chest pain, 1.2%.

In the post marketing experience, there have been rare cases of "torsades de pointes" reported.

CNS Effects

Headaches, usually mild to moderate in severity, have been reported in 2.9% of patients receiving PRIMACOR.

Other Effects

Other adverse reactions reported, but not definitely related to the administration of PRIMACOR include hypokalemia, 0.6%; tremor, 0.4%; and thrombocytopenia, 0.4%.

Post-Marketing Adverse Event Reports

In addition to adverse events reported from clinical trials, the following events have been reported from worldwide post-marketing experience with PRIMACOR:

Isolated spontaneous reports of bronchospasm and anaphylactic shock.

Liver function test abnormalities and skin reactions such as rash.

Administration site conditions: Infusion site reaction.

Read the entire FDA prescribing information for Primacor IV (Milrinone)


In the U.S., 1 in every 4 deaths is caused by heart disease. See Answer

© Primacor IV Patient Information is supplied by Cerner Multum, Inc. and Primacor IV Consumer information is supplied by First Databank, Inc., used under license and subject to their respective copyrights.

Health Solutions From Our Sponsors