How does it work?

Primacor injection contains the active ingredient milrinone, which is a type of medicine called a phosphodiesterase type-3 inhibitors.

Milrinone works be blocking the action of an enzyme called phosphodiesterase which regulates the flow of calcium into and out of muscle cells. Calcium is required for the contraction of muscle cells.

Milrinone acts blocking the action of a chemical called phosphodiesterase. Phosphodiesterase normally regulates the flow of salts into and out of muscle cells. These salts (particularly calcium) are required for the contraction of muscle cells.

By blocking the action of phosphodiesterase, this medicine causes an increase in the amount of calcium entering the muscle cells of the heart. This results in an increased ability of the muscle cells of the heart to contract, thereby allowing the heart to beat with greater force.

Milrinone also causes blood vessels to widen, which decreases the pressure against which the heart has to pump. The overall effect is to improve the heart's ability to pump blood around the body. Milrinone is therefore used in the short term to improve heart function in severe heart failure.

What is it used for?

• Severe congestive heart failure.
• Sudden heart failure, for example after heart surgery.

Use with caution in

• Children.
• Decreased kidney function.
• Low blood potassium levels (hypokalaemia).
• Low blood pressure (hypotension).
• People who have had previous had intensive diuretic treatment.
• Uncontrolled disturbance of normal rhythm in a chamber of the heart (atrial flutter or fibrillation).

Not to be used in

• Low volume of circulating blood (hypovolaemia).

This medicine should not be used if you are allergic to any of its ingredients. Please inform your doctor or pharmacist if you have previously experienced such an allergy.

If you feel you have experienced an allergic reaction, stop using this medicine and inform your doctor or pharmacist immediately.

Pregnancy and breastfeeding

Certain medicines should not be used during pregnancy or breastfeeding. However, other medicines may be safely used in pregnancy or breastfeeding providing the benefits to the mother outweigh the risks to the unborn baby. Always inform your doctor if you are pregnant or planning a pregnancy, before using any medicine.

• The safety of this medicine for use during pregnancy or breastfeeding has not been established. It should not be used by pregnant or breastfeeding women. Seek further medical advice from your doctor.

Side effects

Medicines and their possible side effects can affect individual people in different ways. The following are some of the side effects that are known to be associated with this medicine. Just because a side effect is stated here, it does not mean that all people using this medicine will experience that or any side effect.

Common (affect between 1 in 10 and 1 in 100 people)

• Headache.
• Low blood pressure (hypotension).

Uncommon (affect between 1 in 100 and 1 in 1000 people)

• Low blood potassium level (hypokalaemia).
• Decrease in the number of platelets in the blood (thrombocytopenia).
• Shaking, usually of the hands (tremor).
• Abnormal heart beats (arrhythmias).
• Chest pain (angina).
• Alteration in results of liver function tests.

Very rare (affect less than 1 in 10000 people)

• Rash.
• An extreme allergic reaction (anaphylaxis).
• Breathing difficulties due to a narrowing of the airways (bronchospasm).

The side effects listed above may not include all of the side effects reported by the medicine's manufacturer.

For more information about any other possible risks associated with this medicine, please read the information provided with the medicine or consult your doctor or pharmacist.

How can this medicine affect other medicines?

It is important to tell your doctor or pharmacist what medicinesyou are already taking, including those bought without a prescription andherbal medicines, before you start treatment with this medicine. Similarly,check with your doctor or pharmacist before taking any new medicines whiletaking this one, to make sure that thecombination is safe.

The manufacturers recommend that Primacor should not be used by people taking anagrelide (Xagrid) to reduce the number of platelets in the blood.

Other medicines containing the same active ingredients

There are currently no other medicines available in the UK that contain milrinone.