davidg Huffler1 gill43753 63 Users are discussing this topic

When you first start taking diltiazem you may get a headache, feel flushed, or get swollen ankles. These symptoms usually pass after a few days.

Each time you collect a new supply of diltiazem, check to make sure you have been given the same type of tablets or capsules as before.

Type of medicineCalcium-channel blocker
Used forHigh blood pressure, and angina
Also calledAdizem®; Angitil®; Bi-Carzem®; Dilcardia®; Dilzem®; Kenzem®; Slozem®, Tildiem®; Viazem®; Uard®; Zemtard®
Available asTablets and capsules

Diltiazem is used to treat hypertension (high blood pressure), and prevent angina (chest pain). It works by causing some of your blood vessels to relax and widen. This lowers your blood pressure. It also reduces the force and the rate of your heartbeat, and this helps to prevent angina pains.

Some medicines are not suitable for people with certain conditions, and sometimes a medicine may only be used if extra care is taken. For these reasons, before you start taking diltiazem it is important that your doctor knows:

  • If you are pregnant, trying for a baby or breast-feeding.
  • If you have any problems with your kidneys or liver.
  • If you have a heart condition (such as heart failure, an abnormal heart rhythm, or if you have had a heart attack recently).
  • If you have porphyria (a rare inherited blood disorder).
  • If you are taking any other medicines. This includes any medicines you are taking which are available to buy without a prescription, such as herbal and complementary medicines.
  • If you have ever had an allergic reaction to this or to any other medicine.
  • Before you start taking diltiazem, read the manufacturer's printed information leaflet from inside the pack. The leaflet will give you more information about the specific brand of tablet or capsule you have been given, and a full list of side-effects which you may experience from taking it.
  • There are several different formulations of diltiazem available, so it is important that you take your tablets or capsules exactly as your doctor tells you to. 'Standard' 60 mg tablets are taken three times daily, whereas longer-acting tablets or capsules are taken once or twice daily. Your doctor will tell you which is right for you, and this will also be printed on the label of the pack to remind you. Try to take diltiazem at the same times each day, as this will help you to remember to take your doses.
  • Swallow the tablets or capsules whole with a drink of water - do not chew, break or crush them. You can take diltiazem before or after food.
  • If you forget to take a dose, take it as soon as you remember (unless it is nearly time for your next dose, in which case leave out the missed dose). Do not take two doses together to make up for a forgotten dose.
  • Try to keep your regular appointments with your doctor. This is so your doctor can check on your progress.
  • Your doctor will discuss with you the possibility of unwanted side-effects when you first start taking diltiazem. You may experience headaches, feeling flushed, swollen ankles and some dizziness. These effects usually only last for a few days, but if they continue or become troublesome, you should let your doctor know.
  • Different formulations and brands of diltiazem can act in a slightly different way in your body. Because of this, it is important that you continue to take the same type of tablet or capsule as you have had before. So, each time you collect a prescription, check to make sure your supply looks the same and that the brand name is the same. If you are unsure, or if have any questions about your prescription, please ask your pharmacist to check it for you.
  • Before you buy any medicines or take any 'over-the-counter' remedies, please check with a pharmacist that they are suitable for you to take. This is because some medicines can interact with diltiazem.
  • If you need to have an operation or any medical treatment, always tell the person carrying out the treatment which medicines you are taking. Diltiazem may interfere with the way some anaesthetics work.
  • If you drink alcohol, ask your doctor for advice. Your doctor may recommend that you do not drink alcohol while you are on this medicine, as it may increase the chance that you experience side-effects, such as feeling dizzy or light-headed.
  • Suddenly stopping treatment may cause problems, so keep taking diltiazem unless your doctor tells you otherwise. If it does become necessary for you to stop treatment, your doctor will want you to reduce your dose over a few days.

Along with their useful effects, most medicines can cause unwanted side-effects although not everyone experiences them. The table below contains some of the most common ones. You will find a full list in the manufacturer's information leaflet supplied with your medicine. The unwanted effects often improve as your body adjusts to the new medicine, but speak with your doctor or pharmacist if any of the following continue or become troublesome.

Common diltiazem side-effectsWhat can I do if I experience this?
Feeling dizzy or light-headed, especially when sitting or standing upGetting up more slowly may help. Do not drive or use tools or machines until you feel better
HeadacheAsk your pharmacist to recommend a suitable painkiller
Indigestion, feeling sickStick to simple meals - avoid rich and spicy foods
ConstipationTry to eat a well-balanced diet and drink several glasses of water each day
Swollen ankles, feeling hot and flushed, being aware of your heartbeat, feeling tiredSpeak with your doctor about these if any continue beyond a few days or become troublesome

Important: if you get chest pain, or if your angina pain gets worse or becomes more frequent, contact your doctor as soon as possible.

If you experience any other symptoms which you think may be due to this medicine, speak with your doctor or pharmacist.

  • Keep all medicines out of the reach and sight of children.
  • Store in a cool, dry place, away from direct heat and light.

Never take more than the prescribed dose. If you suspect that you or someone else might have taken an overdose of this medicine, go to the accident and emergency department of your local hospital. Take the container with you, even if it is empty.

This medicine is for you. Never give it to other people even if their condition appears to be the same as yours.

Do not keep out-of-date or unwanted medicines. Take them to your local pharmacy which will dispose of them for you.

If you have any questions about this medicine ask your pharmacist.

Further reading & references

  • British National Formulary; 65th Edition (Mar 2013) British Medical Association and Royal Pharmaceutical Society of Great Britain, London

Disclaimer: This article is for information only and should not be used for the diagnosis or treatment of medical conditions. EMIS has used all reasonable care in compiling the information but make no warranty as to its accuracy. Consult a doctor or other health care professional for diagnosis and treatment of medical conditions. For details see our conditions.

Original Author:
Helen Allen
Current Version:
Peer Reviewer:
Dr Adrian Bonsall
Document ID:
3616 (v23)
Last Checked:
Next Review:
The Information Standard - certified member

Did you find this health information useful?

Yes No

Thank you for your feedback!

Subcribe to the Patient newsletter for monthly healthcare and news updates.

We would love to hear your feedback!

Patient Access app - find out more Patient facebook page - Like our page