Losartán - un bloqueador del receptor de angiotensina
Cozaar
Revisado por pares por Sid DajaniÚltima actualización por Michael Stewart, MRPharmSÚltima actualización 2 Feb 2025
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Take losartan once each day. You can take your doses either before or after a meal.
Any side-effects are usually mild, and can include feeling dizzy or light-headed.
Some painkillers can interfere with losartan and increase the risk of side-effects, so ask a pharmacist for advice before you buy any medicines 'over the counter'.
Do not drink grapefruit juice whilst taking losartan. It can interact with the medicine and alter its effect.
Nota del autor clínico: Michael Stewart 15/11/2018: Following an MHRA update, new advice has been added to this leaflet for people also taking the blood pressure medicine hydrochlorothiazide. Hydrochlorothiazide is only available in the UK in combination with other medicines used to treat high blood pressure. It may be available on its own in other countries. For more information see the warning below in 'can this medicine cause problems?' or view the Alerta de la MHRA.
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About losartan
Tipo de medicamento | An angiotensin-II receptor antagonist |
Usado para | High blood pressure; heart failure; kidney disease associated with diabetes |
También llamado | Cozaar®; |
Disponible como | Comprimidos |
Losartan is an angiotensin receptor blocker. It is also called an angiotensin-II receptor antagonist, or an AIIRA. You will have been prescribed losartan for one of the following reasons:
To lower blood pressure if your blood pressure is too high (hypertension).
To help your heart if it is not beating as well as it should (insuficiencia cardíaca).
To help protect your kidneys if you have kidney disease associated with type 2 diabetes mellitus.
Losartan works by blocking the effect of a substance in your body called angiotensin II. Angiotensin II causes your blood vessels to narrow and also leads to the production of another substance called aldosterone, which increases the amount of fluid in your blood. By preventing the action of angiotensin II, losartan reduces how much work your heart has to do and lowers your blood pressure. It also has a protective effect on your kidneys.
You may be prescribed losartan to take on its own, or alongside other medicines to help your condition. There is a combination tablet available called Cozaar-Comp® which contains losartan with a diuretic called hydrochlorothiazide. This combination tablet can be prescribed to people with high blood pressure to help reduce the total number of tablets that need to be taken each day.
Before taking losartan
Volver al contenidoSome medicines are not suitable for people with certain conditions, and sometimes a medicine can only be used if extra care is taken. For these reasons, before you start taking losartan it is important that your doctor knows:
Si estás embarazada o amamantando.
If you know you have a blockage of the artery which supplies blood to your kidneys, a condition called renal artery stenosis.
If you have any problems with your heart valves or heart muscle.
Si tienes un problema con el funcionamiento de tu hígado.
Si está tomando otros medicamentos. Esto incluye cualquier medicamento que esté tomando y que esté disponible para comprar sin receta, así como medicamentos herbales y complementarios.
If you have ever had an allergic reaction to a medicine, or if you have had any other type of allergic reaction.
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How to take losartan
Volver al contenidoBefore you start the treatment, read the manufacturer's printed information leaflet from inside the pack. It will give you more information about losartan and will provide you with a full list of the side-effects which you could experience from taking it.
Take losartan once each day, exactly as your doctor tells you to. There are several different strengths of tablet available. When you first start treatment your doctor may gradually increase the strength of the tablets to suit your condition. Each time you collect a fresh supply, it's a good idea to check the strength on the packet to make sure they are what you are expecting.
Try to take losartan at the same time of day each day. For most people this will be in the morning. Taking your doses at the same time each day will help you to remember to take losartan regularly.
Swallow the tablet whole with a drink of water. You can take losartan either before or after a meal.
If you forget to take a dose, take it as soon as you remember. If you do not remember until the following day, miss out the forgotten dose. Do not take two doses at the same time to make up for a forgotten dose.
Obteniendo el máximo de tu tratamiento
Volver al contenidoTry to keep your regular appointments with your doctor. This is so your progress can be monitored. Your doctor may want you to have some blood tests from time to time to check on your kidneys, and also how much potassium is in your blood.
If you buy any medicines, check with a pharmacist that they are suitable to take with losartan. This is because some anti-inflammatory painkillers (such as aspirin and ibuprofen) can interfere with the way it works, and also may increase the risk of side-effects.
It is very important that you follow any dietary and lifestyle advice that you have been given by your doctor, such as eating a healthy diet, not smoking, and taking regular exercise.
If you drink alcohol, ask your doctor for advice. Your doctor may recommend that you do not drink alcohol while you are on losartan because it will increase the risk of side-effects, such as feeling dizzy or faint.
Try to avoid salt substitutes which contain potassium. This is because the substitutes will increase the amount of potassium in your blood and this can cause problems.
If you are having an operation or dental treatment, tell the person carrying out the treatment that you are taking losartan. This is because your blood pressure may drop too low if you are given some anaesthetics.
Treatment with losartan is usually long-term unless you experience an adverse effect. Continue to take the tablets regularly, unless you are advised otherwise by your doctor.
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Can losartan cause problems?
Volver al contenidoAlong 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 losartan. 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 losartan side-effects (these affect fewer than 1 in 10 people) | ¿Qué puedo hacer si experimento esto? |
Feeling tired, or dizzy and light-headed when you stand up (due to low blood pressure) | Getting up and moving more slowly should help. If you begin to feel dizzy, sit for a few minutes before you stand up again |
Changes in the amount of potassium in your blood | You will have blood tests from time to time to check for this |
If you are also taking hydrochlorothiazide in combination with this medicine:
Los estudios han sugerido que tomar dosis más altas de hidroclorotiazida durante largos períodos de tiempo puede aumentar el riesgo de ciertos tipos de cáncer de piel.
Informe a su médico si alguna vez ha sido tratado por cáncer de piel.
Informe a su médico sobre cualquier lunar nuevo o cambiado, o marcas preocupantes en su piel.
Use a sunscreen in strong sunlight. Do not use sunbeds.
Si experimenta otros síntomas que cree que pueden deberse al medicamento, hable con su médico o farmacéutico para obtener más consejos.
How to store losartan
Volver al contenidoMantenga todos los medicamentos fuera del alcance y la vista de los niños.
Store the tablets in a cool, dry place, away from direct heat and light.
Información importante sobre todos los medicamentos
Volver al contenidoInformación importante sobre todos los medicamentos
Nunca tome más de la dosis prescrita. Si sospecha que usted u otra persona podría haber tomado una sobredosis de este medicamento, acuda de inmediato al departamento de accidentes y emergencias de su hospital local. Lleve el envase con usted, incluso si está vacío.
Este medicamento es para ti. Nunca lo des a otras personas, incluso si su condición parece ser la misma que la tuya.
No guardes medicamentos caducados o no deseados. Llévalos a tu farmacia local, que se encargará de desecharlos por ti.
Si tienes alguna pregunta sobre este medicamento, consulta a tu farmacéutico.
Informar efectos secundarios de un medicamento o vacuna
Si experimenta efectos secundarios, puede reportarlos en línea a través de sitio web de la Tarjeta Amarilla.

¿Inseguro sobre mezclar medicamentos?
Verifica posibles interacciones entre medicamentos, suplementos y alimentos antes de tomarlos juntos.
Lecturas adicionales y referencias
- Manufacturer's PIL, Cozaar® 12.5 mg, 25 mg, 50 mg and 100 mg Film-Coated Tablets; Organon Pharma (UK) Limited, The electronic Medicines Compendium. Dated December 2022.
- Medicamentos Completos BNF 89ª Edición; Asociación Médica Británica y Sociedad Real de Farmacia de Gran Bretaña, Londres.
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Historial del artículo
La información en esta página está escrita y revisada por pares por clínicos calificados.
Próxima revisión: 2 Feb 2028
2 Feb 2025 | Última versión

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