Explanation

Colistimethate sodium (also called Colomycin® and Promixin®) is a medicine that helps your body to fight infections.

It is usually used to fight chest infections that you can get if you have cystic fibrosis.

Colistimethate sodium is a type of medicine called an antibiotic.

How does it work?

Colistimethate sodium works by killing the bacteria that cause lung infections. This gives your immune system help to fight off these infections.

What does it look like?

Colistimethate sodium comes as a powder in a small bottle called a vial. To take it, it is mixed with water and you breathe it in using a special machine called a nebuliser.

A nebuliser is a pump with a face mask that lets you breathe in medicines as tiny droplets. Your doctor will show you and the adults who look after you how to use one.

When do I have to take it?

You will probably need to take one or two vials, two or three times a day, spread out evenly through the day.

Your doctor or nurse will help you take it the first time.

But what if I don't feel like taking it?

It's very important that you take your colistimethate sodium, as it will help you to fight off your chest infections.

You must take all of the colistimethate sodium that your doctor gives you. Don't stop taking it before it's all gone, even if you feel better, because if you do some bacteria may survive and the chest infectioncould come back.

What should I do if I forget to take it?

If you forget to take your colistimethate sodium, take it as soon as you remember, unless it is nearly time for your next dose.

Don't take twice as much the next time to catch up. Remember the three Ds: Don't Double Dose!

How much should I take?

Your doctor will tell you much colistimethate sodium to take. This depends on how bad your chest infection is, and how old you are.

You will probably need to take one or two vials, two or three times a day, spread out evenly through the day.

What are the most likely side effects I might get?

Using a nebuliser to take colistimethate sodium can make your chest feel tight and make it difficult to breathe. It can also make you cough or feel wheezy.

This is why you need to be with a doctor or nurse when you first take it.

What other side effects might I get?

Colistimethate sodium can sometimes give you a sore throat or make your mouth hurt.

It can also cause a skin rash if you are allergic to it. If this happens, stop using colistimethate sodium immediately and tell your doctor.

Are there any other side effects that you haven't mentioned?

Colistimethate sodium can sometimes cause problems with your kidneys, although this is not very likely.

If any of these side effects make you feel very unwell, or you notice any others, you talk to your doctor as soon as you can.

Is it safe for me to be taking it?

Don't take colistimethate sodium if:

You have an illness called myasthenia gravis, which makes your muscles get tired very easily

You know you are allergic to it

Before taking colistimethate sodium, tell your doctor if you have:

Problems with your kidneys

A rare illness called porphyria that affects your blood

Asthma

Is it okay for me to take colistimethate sodium if I'm already taking other medicines?

You should tell your doctor about any other medicines that you are taking, or have taken recently, including herbal medicines.

It's especially important to tell your doctor if you are taking any other antibiotics, especially gentamicin, amikacin, netilmicin or tobramycin.

You should also tell your doctor if you are going to have an operation under a general anaesthetic, as colistimethate sodium may stop the anaesthetic from working properly.

Do I need to know anything else about it?

Don't use your colistimethate sodium if it is after the date printed on the bottle it comes in, because it might not work properly. Ask your doctor for some more colistimethate sodium to use instead.

What if I have any more questions?

If you have any other questions, you can ask your doctor, or chat to other people with cystic fibrosis in the Medikidz forums and virtual world, Mediland.