Nifedipine

What the treatment is and why it's prescribed

If your symptoms fail to improve, you may be prescribed nifedipine. This is the only medicine licensed to treat Raynaud's phenomenon in the UK. It doesn't cure Raynaud's, but can help to relieve the symptoms.

Nifedipine is used alone or together with other medicines to treat severe chest pain (angina) or high blood pressure (hypertension). High blood pressure adds to the workload of the heart and arteries. If it continues for a long time, the heart and arteries may not function properly. This can damage the blood vessels of the brain, heart, and kidneys, resulting in a stroke, heart failure, or kidney failure. High blood pressure may also increase the risk of heart attacks. These problems may be less likely to occur if blood pressure is controlled.

Nifedipine is a calcium channel blocker. It works by affecting the movement of calcium into the cells of the heart and blood vessels. As a result, nifedipine relaxes blood vessels and increases the supply of blood and oxygen to the heart while reducing its workload. This medicine is available only with your doctor's prescription.

In deciding to use a medicine, the risks of taking it must be weighed up against the likely benefits. This is a decision that you and your doctor will make. For this medicine, the following should be considered:

Allergies

Tell your doctor if you have ever had any unusual or allergic reaction to this medicine or any other medicines. Also tell your health care professional if you have any other types of allergies, such as to foods, dyes, preservatives, or animals. For non-prescription products, read the label or package ingredients carefully.

Children aged 16 and under

Appropriate studies have not been performed on the relationship of age to the effects of nifedipine in children aged 16 and below. Safety and efficacy regulations have not been established.

Older people

Appropriate studies performed to date have not demonstrated problems that would limit the usefulness of nifedipine in the elderly. However, elderly patients are more likely to have age-related kidney, liver, or heart problems which may require caution and an adjustment in the dose for patients receiving nifedipine.

How to take it

Depending on the pattern of your symptoms and how well you respond to treatment, you may be asked to take your medication every day. Alternatively, you may only need to take it as prevention; for example, during a sudden snap of cold weather.

Nifedipine comes as 'long acting' (slow-release) tablets or capsules, and can be referred to as Nifedipress MR and Tensipine MR. These release nifedipine evenly throughout the day. This means you don't need to take them as often.

To decide the correct dose for you, your doctor will check your blood pressure. Depending on why you're taking nifedipine, the usual starting dose is:

long acting tablets or capsules: 10mg twice a day (every 12 hours) or 20 to 30mg 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.

If the starting dose isn't working well enough (your blood pressure doesn't 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 long acting capsules or tablets are:

40mg twice a day or 90mg once a day (total of 80 or 90mg a day)

Swallow the extended release tablet whole. Do not break, crush, or chew it. It is best to take this tablet on an empty stomach.

If you are taking the extended-release tablets, part of the tablet may pass into your stool after your body has absorbed the medicine. This is normal and nothing to worry about.

The dose of this medicine will be different for different people. Follow your doctor's orders or the directions on the label. The following information includes only the average doses of this medicine. If your dose is different, do not change it unless your doctor tells you to do so.

The amount of medicine that you take depends on the strength of the medicine. Also, the number of doses you take each day, the time allowed between doses, and the length of time you take the medicine depend on the medical problem for which you are using the medicine.

Nifedipine starts to work on the day you start taking it, but it may take a couple of weeks for full effect. Nifedipine is generally safe to take for a long time. In fact, it works best when you take it for a long time.

What are the possible side effects?

Along with its needed effects, like all medicines, nifedipine may cause some side effects. Although not all of these side effects may occur, if they do occur they may need medical attention.

Check with your doctor immediately if any of the following side effects occur:

More common -

Bloating or swelling of the face, arms, hands, lower legs, or feet
cough
difficult or laboured breathing
dizziness or lightheadedness
fast, irregular, pounding, or racing heartbeat or pulse
feeling of warmth
headache
muscle cramps
rapid weight gain
shakiness in the legs, arms, hands, or feet
shortness of breath
tightness in the chest
tingling of the hands or feet
trembling or shaking of the hands or feet
unusual weight gain or loss
weakness
wheezing

Some side effects may occur that usually do not need medical attention. These side effects may go away during treatment as your body adjusts to the medicine. Also, your healthcare professional may be able to tell you about ways to prevent or reduce some of these side effects, so always check with them if you are unsure.

Other side effects not listed may also occur in some patients. If you notice any other effects, talk to your healthcare professional. Do not stop taking this medicine without first checking with your doctor, as they may want you to gradually reduce the amount you are using before stopping completely.

Make sure any doctor or dentist who treats you knows that you are using this medicine. You may need to stop using this several days before having surgery or medical tests. This medicine may affect the results of certain medical tests.

Can the treatment affect other medications or treatments?

Although certain medicines should not be used together at all, in other cases two different medicines may be used together even if an interaction might occur. In these cases, your doctor may want to change the dose, or other precautions may be necessary. When you are taking this medicine, it is especially important that your healthcare professional knows if you are taking anything else.

Using different drugs together may be required in some cases, and your doctor may change the dose or how often you use one or both of the medicines.

Other Interactions

Certain medicines should not be used at or around the time of eating food or eating certain types of food since interactions may occur.

Can I drink alcohol with this treatment?

Using alcohol or tobacco with certain medicines may also cause interactions to occur.

Using this medicine in some circumstances may cause an increased risk of certain side effects but might be unavoidable in some cases. If used together, your doctor may change the dose or how often you use this medicine, or give you special instructions about the use of food, alcohol, or tobacco.

Grapefruit juice shouldn't be taken with this medicine.

Can this treatment affect fertility, pregnancy or breastfeeding?

Studies in women suggest that this medication poses minimal risk to the infant when used during breastfeeding.

What if I forget to take it?

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

three 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 four hours until your next dose is due. In this case leave out that 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 is due. In this case leave out that dose and take your next dose at the usual time.
Never take a double 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 your pharmacist for advice on other ways to help you remember to take your medicine.

What if I take too much?

If you take too much nifedipine by accident, contact your doctor or go to your nearest hospital straight away.

An overdose of nifedipine can cause dizziness and irregular heartbeats; and make you feel sick, confused, and sleepy.

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

If you need to go to hospital, don't drive yourself - get someone else to take you or call for an ambulance. If you can, take the box or the leaflet inside the packet plus any remaining medicine with you to the hospital.

Whilst it's important to understand that taking medicine may have side effects, the benefits of taking the right medication may outweigh these. Do speak to your GP about any concerns you may have or contact our Helpline to discuss your condition.

Why not contact people who have the same conditions and have used nifedipine, join our Facebook and Twitter groups and ask a question or on our Health Unlocked.

Raynaud's attacks can be restricted if you can keep your core temperature warm. Read about keeping warm on here or visit the shop to view products to help prevent your Raynaud's attacks, as recommended by our community.

Content referenced from the NHS and Mayo Clinic.