How and when to take nifedipine

Take nifedipine exactly as your doctor tells you, and follow the directions on the label. If you're not sure, check with your doctor or pharmacist.

Nifedipine comes as standard capsules, or more commonly as slow-release tablets or capsules. These often have letters (XL, LA, SR, MR) or "Retard" after the brand name.

Slow-release tablets and capsules release the medicine into your body gradually throughout the day. This usually means you do not need to take them as often.

Dosage and strength

Nifedipine comes as:

• 5mg and 10mg standard capsules
• 10mg, 20mg, 30mg, 40mg and 60mg slow-release tablets and capsules

Your dose of nifedipine depends on why you need the medicine and what kind your doctor has prescribed.

To decide the correct dose for you, your doctor will check your blood pressure. The usual starting dose is:

• standard capsules or liquid – 5mg, taken 3 times a day (every 8 hours)
• slow-release tablets or capsules – 10mg, taken twice a day (every 12 hours), or 20 to 30mg, taken once a day (every 24 hours, preferably in the morning)

If a doctor prescribes it for your child, the dose will usually be lower. It will depend on how old your child is and how much they weigh.

How to take it

Nifedipine is very sensitive to light, so make sure you take your tablet or capsule as soon as you take it out of the packet.

You can take nifedipine at any time of day, but try to make sure it's around the same time (or times) every day.

Swallow the capsules or tablets whole with a drink of water. Do not break, crush, chew or open up the capsules unless your doctor or pharmacist has said you can.

It usually does not matter if you take nifedipine with or without food, but check the leaflet of the brand you're taking because the advice can vary.

There are several brands of slow-release nifedipine, which may not all be the same. Make sure you stick to the same brand if possible and follow the directions on how to take it carefully.

With some of the slow-release tablets, you might notice what looks like a whole tablet in your poo. Do not worry, this is normal. It's just the outer shell of the tablet which your body has not digested.

If you're taking nifedipine as a liquid, shake the bottle well. The medicine will come with a plastic syringe or spoon to help you take the right amount. If you do not have a plastic syringe or spoon, ask your pharmacist for one. Do not use a kitchen teaspoon as it will not measure the right amount.

How long to take it for

Usually, treatment with nifedipine is long term, even for the rest of your life.

Changing your dose

If the starting dose is not working well enough (your blood pressure does not come down enough, or you are still getting symptoms), you may need to increase your dose. If you're bothered by side effects, you may need to stay on a lower dose.

The usual maximum doses of nifedipine are:

• standard capsules or liquid – 20mg, taken 3 times a day (total of 60mg a day)
• slow-release capsules or tablets – 40mg, taken twice a day, or 90mg once a day (total of 80mg or 90mg a day)

If you forget to take it

If you forget to take a dose and you usually take nifedipine:

• 3 times a day – leave out that dose and take your next dose at the usual time
• twice a day – take it as soon as you remember unless it is less than 4 hours until your next dose. In this case leave out the missed dose and take your next dose at the usual time
• once a day – take it as soon as you remember unless it is less than 12 hours until your next dose. In this case leave out the missed dose and take your next dose at the usual time

Never take 2 doses to make up for a forgotten one.

If you often forget doses, it may help to set an alarm to remind you. You could also ask your pharmacist for advice on other ways to help you remember to take your medicine.

If you take too much

The amount of nifedipine that can lead to an overdose varies from person to person.

Taking too much nifedipine can make you feel:

• dizzy
• like your heart is not beating normally (irregular heartbeats)
• sick (nausea)
• confused
• sleepy

Stopping taking nifedipine

Talk to your doctor if you want to stop taking nifedipine. Stopping may cause your blood pressure to go up, and this may increase your risk of heart attack and stroke.

If you're bothered by any side effects, your doctor may be able to prescribe you a different medicine.