Nifedipine

About nifedipine

Nifedipine is given to treat high blood pressure (hypertension), or to help prevent angina chest pain. It is also prescribed in the treatment of Raynaud's phenomenon, which is a condition caused by poor circulation to the hands and feet. You will have been prescribed it for one of these reasons.

Nifedipine works by causing some of your blood vessels to relax and widen. This lowers your blood pressure. It also increases the flow of blood to places like your hands and feet. Nifedipine also reduces the force and the rate of your heartbeat, and this helps to prevent angina chest pain. It does all of these things by blocking the amount of calcium that goes into the 'smooth' muscle cells in the walls of your blood vessels and in your heart. Calcium is needed for muscles to contract, so reducing the amount of calcium causes the muscle cells to relax.

Nifedipine is available as 'short-acting' capsules (which are taken three times daily) and also as modified-release tablets and capsules (which are taken once or twice daily). Short-acting capsules are generally prescribed to treat Raynaud's, whilst the modified-release tablets and capsules are prescribed for people with high blood pressure or angina. Modified-release tablets and capsules have letters such as 'XL', 'LA', 'SR', 'MR', or 'Retard' after their brand name - these release nifedipine slowly and evenly throughout the course of the day..

Before taking nifedipine

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 nifedipine it is important that your doctor knows:

• If you have any heart problems (other than angina or high blood pressure).

• If you are pregnant or breastfeeding.

• If you have diabetes (diabetes mellitus).

• If you have problems with the way your liver works.

• If you are taking or using 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 a medicine.
  

How to take nifedipine

• Before you start this treatment, read the manufacturer's printed information leaflet from inside your pack. It will give you more information about the brand of nifedipine your doctor has prescribed for you. It will also provide you with a full list of the side-effects which you may experience from taking nifedipine.

• Take nifedipine exactly as your doctor tells you to. Your doctor or pharmacist will tell you how often to take the tablets/capsules. The dose will also be printed on the label of the pack to remind you what your doctor said.

• Swallow the tablet/capsule with a drink of water. Do not break, crush or chew the tablets/capsules, as this could affect the way the medicine is released into your bloodstream. You can take nifedipine either 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 nifedipine you may experience headaches, feeling flushed, 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.

• 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.

• Treatment with nifedipine is often long-term. Continue to take the tablets/capsules unless you are told otherwise by your doctor. If it is necessary for you to stop, your doctor may want you to reduce your dose over a few days, as there is some evidence to suggest that stopping taking nifedipine suddenly can cause some symptoms to return.

• If you buy any medicines, always check with a pharmacist that they are suitable to take with your other medicines. Some anti-inflammatory painkillers may reduce the effectiveness of nifedipine.

• If you need to have an operation or any medical treatment, always tell the person carrying out the treatment which medicines you are taking. Nifedipine and some anaesthetics can interact, meaning that unwanted effects are more likely.

• It is not advisable for you to drink grapefruit juice while you are on nifedipine. This is because a chemical in grapefruit juice can increase the amount of nifedipine in your bloodstream and this increases the risk of side-effects.

• There are several brands of modified-release nifedipine available and your treatment could be affected by switching between brands. Each time you collect a new supply from your pharmacy, check to see if the tablets/capsules are the same as before. If your medicine or packaging looks different from what you have had before, discuss this with your pharmacist who will advise you.

• Parts of some modified-release tablets pass through the digestive system intact and it is possible to see bits of the tablets when you go to the toilet. This is nothing to be concerned about and it does not stop the medicine from working.

• If you have diabetes you may need to check your blood glucose more frequently for a time. Nifedipine can affect the levels of sugar in your blood but your doctor will advise you about this.

Can nifedipine 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 nifedipine. 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.

Important: a few people taking nifedipine have experienced worsening of chest pain at the start of treatment - if this happens to you, you must let your doctor know straightaway.

If you experience any other symptoms which you think may be due to the tablets, speak with your doctor or pharmacist for further advice.

How to store nifedipine

• Keep all medicines out of the reach and sight of children.

• Store in a cool, dry place, away from direct heat and light.

Important information about all medicines