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How and when to take diltiazem - Brand names: Adizem, Angitil, Tildiem, Viazem, Zemtard

Take diltiazem exactly as your doctor has told you. If you're not sure, check with your doctor or pharmacist.

Dosage

Your dose of diltiazem depends on why you need the medicine and what kind your doctor has prescribed. It's important to keep taking the same brand of diltiazem once you have started.

Diltiazem tablets or capsules come as standard or slow-release. Your doctor will tell you whether you need to take them once a day or in divided doses throughout the day.

Slow-release tablets and capsules release diltiazem slower than the standard tablets and capsules.

Changes to your dose

If the dose you start on does not reduce your blood pressure enough or help to control your angina, then your doctor will gradually increase your dose.

Your doctor may also lower your dose if side effects bother you.

How to take tablets or capsules

You can take diltiazem with or without food. Swallow diltiazem tablets or capsules whole, usually with a glass of water. Do not chew or crush them.

If you find tablets or capsules difficult to swallow, speak to a pharmacist or doctor, as there may be other options.

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

With some of the capsules and tablets you might notice what looks like a whole capsule or tablet in your poo. Do not worry, this is normal. It's just the empty outer shell of the capsule or tablet which your body does not digest.

How to use cream or ointment

For an anal fissure, you'll need to apply a 2.5cm length of diltiazem cream or ointment to the broken skin on your anus, twice a day, usually for 6 to 8 weeks. Follow the instructions on the packaging.

How long to take it for

If you're taking diltiazem for high blood pressure or angina, you'll usually take it long term, even for the rest of your life.

Talk to your doctor if you want to stop taking diltiazem. Stopping may cause your blood pressure to rise and this may increase your risk of a heart attack or stroke.

If you're using it to treat an anal fissure, you'll use the cream or ointment to heal the tear on your anus until it's no longer painful to poo. This will mean the tear has healed. This usually takes around 6 to 8 weeks.

If you stop using the cream before a fissure has fully healed, it may tear again.

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

Important

Keep taking diltiazem even if you feel well, as you'll still be getting the benefits of the medicine.

If you forget to take it

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

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

Never have an extra dose to make up for a forgotten one.

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

If you take too much

Too much diltiazem can make you feel faint, dizzy or sleepy. This is because it can cause your heart to beat irregularly.

Urgent advice: Contact 111 for advice if:

  • you take more than your prescribed dose of diltiazem

Go to 111.nhs.uk or call 111

Information:

If you need to go to A&E, do not drive. Ask someone to drive you or call 999 and ask for an ambulance.

Bring the diltiazem packet or leaflet inside it, any remaining medicine, and any other medicines you take.

Page last reviewed: 10 March 2023
Next review due: 10 March 2026