Phenindione - an anticoagulant

About phenindione

Phenindione is an anticoagulant medicine, which means that it increases the time it takes for your blood to clot. It works by reducing the effects of vitamin K, which is a vitamin your body uses to make blood-clotting factors.

Phenindione is prescribed to prevent harmful blood clots from forming if you have a condition that puts you at risk of this happening, such as atrial fibrillation, or if you have had a heart valve replacement. It is also given to prevent any clots that may have already formed in the blood vessels of your legs, lungs or heart from becoming larger and causing problems. Another anticoagulant, called warfarin, is usually prescribed in preference to phenindione but if warfarin is not suitable for you, you may be prescribed phenindione instead.

Before taking phenindione

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 phenindione it is important that your doctor knows:

• Si está embarazada, esperando un bebé o en período de lactancia.

• Si tiene cortes o heridas.

• Si padece alguna enfermedad que aumente el riesgo de hemorragia, como una úlcera de estómago, si le han operado recientemente o si ha sufrido un derrame cerebral.

• Si tiene algún problema con el funcionamiento del hígado o de los riñones.

• Si tiene la tensión alta.

• Si le han dicho que tiene una infección del corazón, llamada endocarditis bacteriana.

• Si toma o utiliza otros medicamentos. Esto incluye cualquier medicamento que esté tomando y que pueda adquirirse sin receta, así como medicamentos a base de plantas y complementarios.

• Si alguna vez ha tenido una reacción alérgica a un medicamento.

How to take phenindione

• Before you start the treatment, read the manufacturer's printed information leaflet from inside the pack of tablets and any additional information you have been given by your doctor. These will give you more information about phenindione and will provide you with a full list of the side-effects which you may experience from taking it.

• Take phenindione once a day, exactly as you have been advised by your doctor or anticoagulant clinic. You should aim to take phenindione at the same time each day. This will help keep the levels of the medicine in your blood steady and will also help you to avoid missing any doses. Your doctor will tell you how many tablets to take for each dose. Phenindione tablets are available in two different strengths: 10 mg and 25 mg. Your dose may be made up of more than one strength of tablet. Swallow the tablet(s) with a drink of water.

• If you forget to take a dose at your usual time, you can take it as soon as you remember if it is still within two or three hours of your usual time. If you do not remember until after this time, do not take the missed dose but do remember to take your next dose when it is due. Never take two doses together to make up for a forgotten dose, and remember to let your doctor know about any missed doses when you next have your blood test.

• Continue to take phenindione tablets regularly until your doctor tells you to stop. A course of treatment typically lasts from six weeks to three months, although some people may be advised to continue taking the tablets long-term.

Aproveche al máximo su tratamiento

• You may be given a yellow 'Oral Anticoagulant Therapy' booklet; please read this carefully as it gives you important information, such as when you should contact a doctor for advice. You will also be given an 'Anticoagulant Alert Card' which you should carry with you at all times. In case of an emergency, a doctor will need to know that you are taking phenindione.

• You will need to have regular blood tests to check on how quickly your blood clots. Blood tests may be needed quite often at first but should reduce in frequency quite quickly. The extent to which phenindione is working is measured by the International Normalised Ratio (INR), which is a measure of the ability of your blood to prevent clotting. The amount of phenindione that you need to take will depend upon the result of these blood tests and this is why your dose may change from time to time. The aim is to get the dose of phenindione just right so your blood does not clot as easily as normal, but not so much as to cause bleeding problems.

• Phenindione may make your urine look pink or orange. This is completely harmless and is nothing to worry about.

• Cambiar repentinamente de dieta puede afectar a su INR, sobre todo si empieza a comer más verdura y ensalada que antes. No debe empezar una dieta de adelgazamiento sin consultarlo antes con su médico. Un cambio importante en la dieta significará que necesitará un seguimiento más estrecho, ya que puede ser necesario ajustar su dosis.

• Beba alcohol sólo en pequeñas cantidades, ya que esto puede afectar a los niveles del medicamento en su organismo. Limite la cantidad de alcohol que bebe a un máximo de una o dos unidades al día y nunca beba en exceso.

• If you buy any medicines, check with a pharmacist that they are safe to take with phenindione. For example, you should not take some painkillers (such as aspirin and other anti-inflammatory painkillers) and some vitamin and herbal preparations. If you need to take a painkiller, you may take paracetamol but you should let your doctor know if you need to take it regularly.

• Because phenindione is used to prevent blood clots from forming, you should try to avoid activities that could cause you to cut or bruise yourself, such as contact sports. Let your doctor know if you have any falls or injuries.

• You should avoid getting pregnant while you are taking phenindione as it may cause harm to an unborn baby. Make sure you have discussed with your doctor which types of contraception are suitable for you and your partner.

• If you are due to have any injections, or any medical or dental treatment, please tell the person carrying out the treatment that you are taking an anticoagulant, and show them your treatment booklet. It is important that they know you may take longer to stop bleeding. If you are due to have surgery, you may be advised to stop taking phenindione for a few days and be given injections instead.

Can phenindione 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 side-effects associated with phenindione - the most common ones are bleeding and bruising. You will find a full list in the manufacturer's information leaflet supplied with your medicine. Speak with your doctor or pharmacist if any of the following continue or become troublesome.

Si experimenta cualquier otro síntoma que crea que puede deberse a los comprimidos, hable con su médico o farmacéutico para que le aconsejen.

How to store phenindione

• Mantenga todos los medicamentos fuera del alcance y de la vista de los niños.

• Almacenar en un lugar fresco y seco, lejos del calor y la luz directos.

Información importante sobre todos los medicamentos