Diltiazem can be used to treat Raynaud's. 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.

Before taking Diltiazem

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 high blood sugar levels (diabetes mellitus).
  • If you have a rare inherited blood disorder called porphyria.
  • If you are taking any other medicines. This includes any medicines you are taking which are available to buy without a prescription, as well as herbal and complementary medicines.
  • If you have ever had an allergic reaction to this or to any other medicine.

How to take diltiazem

  • 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 a day or twice a day. 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.

Getting the most from your treatment

  • 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.
  • If you have diabetes you may need to check your blood sugar (glucose) level more often. This is because diltiazem may raise your glucose levels. Ask your doctor or pharmacist for advice.
  • 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.
  • Drinking grapefruit juice may affect the amount of diltiazem in your blood and can make you more likely to experience side-effects. Let your doctor or pharmacist know if you enjoy drinking grapefruit juice and wish to continue.
  • 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.

Can diltiazem cause problems?

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 associated with diltiazem. 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-effects and what to do.

Feeling dizzy or light-headed, especially when sitting or standing up - getting up more slowly may help. Do not drive and do not use tools or machines until you feel better.

Headache - Drink plenty of water and ask your pharmacist to recommend a suitable painkiller. If the headache continues, speak with your doctor.

Indigestion, feeling sick (nausea) - Stick to simple meals - avoid rich and spicy foods

Constipation - Try 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 tired - Speak 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.

How to store diltiazem

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