Treatment for: Hypertension (High Blood Pressure)

Type of drug: Angiotensin receptor blocker

Prescription or over-the-counter: Prescription-only medication

Branded or generic: Generic

Active ingredient: Losartan potassium

Dosages available: 50mg and 100mg

Time to start working: 3-4 hours

Common side effects include: Dizziness, feeling weak or tired, drowsiness, headache, nausea, cough, shortness of breath

Losartan is a prescription medicine that is used to treat high blood pressure and heart failure. It is also prescribed for people with both diabetes and kidney disease. 

Losartan can protect you against heart attacks, kidney problems and strokes. It is also used if you have had a heart attack before and can also improve your recovery rate. 

Losartan is taken as a tablet and belongs to a group of medicines called angiotensin II receptor blockers (ARBs). Other medications that are used to treat high blood pressure are known as beta-blockers, calcium channel blockers, or angiotensin-converting enzyme (ACE) inhibitors. 

Losartan works by widening and relaxing your blood vessels. This helps to lower your blood pressure, and makes it easier for your heart to pump blood around your body. 

Losartan can begin to lower your blood pressure after 6 hours and will stay in your system for between 10 to 24 hours. It will normally take 3 to 6 weeks for losartan to have the fullest effect.

You might not have any symptoms if you have high blood pressure. This means that you may not feel any different when taking losartan, but this does not mean that the medication is not working.

You should only stop taking losartan if your doctor tells you to. This is because it may not be safe for you to stop taking losartan without reducing your dose over a short period of time as this can increase your risk of having a heart attack or a stroke. 

The usual starting dose is 50mg to be taken once a day. Your doctor will tell you how to take losartan when it is prescribed for you. You might be told to take your first dose at bedtime. This is because losartan can make you feel dizzy at first. After this, you should be able to take losartan at any time of day.

You can take losartan with or without food. You might find it easier to swallow your tablets with a glass of water. You should also try to take losartan at the same time each day as recommended because this helps you get the full effect of the medication.

What if I miss a dose?

You should take your missed dose as soon as you remember. If you do not remember until the next day you should skip the missed dose. Do not take a double dose of losartan.

Your GP will decide whether losartan 50mg or 100mg are suitable for you. Depending on how well you adjust to your medication, your GP may increase or decrease the dosage in the future. It is important that you visit your local surgery regularly for check-ups, so your GP can monitor your blood pressure and make sure your treatment remains effective.

The dose that your doctor will prescribe also depends on what losartan is being used to treat.

High blood pressure

Adults aged between 18 and 75: 50mg daily for the first few weeks, increased to 100mg per day if needed

Adults over the age of 76: sometimes the starting dose may be lower, at 25mg daily, increased to up to 100mg if needed

Heart failure

Adults of all ages: 12.5mg daily, increased gradually to a maximum of 150mg if needed

Can I get losartan online?

You can buy losartan online from just £23 with Superdrug Online Doctor, with discreet delivery straight to your door. All you have to do is complete a short online questionnaire about your health, and our doctors can prescribe losartan if it is safe and appropriate for you. All orders are delivered in discreet packaging, and our doctors can provide free expert advice if you have any questions about losartan or your blood pressure.

How much does losartan cost?

You can get a 3 month supply of losartan (50mg or 100mg) for £23.

Can you get losartan on the NHS?

Yes, losartan is available on the NHS. You will need to book an appointment with your GP to get a prescription for losartan. Or you can fill out our simple questionnaire and get your prescribed medication without having to leave your home.

Can you get losartan over the counter?

No, you cannot get losartan over the counter without a prescription.

All medicines can have side effects but not everybody will get them. Some side effects are mild, and may go away after a little while.

Common side effects include:

• dizziness and vertigo
• headaches
• coughing
• feeling or being sick
• diarrhoea
• joint or muscle pain

If you find these side effects unmanageable or they do not go away, you should speak to your doctor or pharmacist.

Uncommon side effects include:

• liver problems
• very bad tummy pain
• pale skin, tiredness, fainting, bleeding, sore throat, and fevers - these could be sign of a blood disorder
• irregular heartbeat, weakness, tingling, or pins and needles

You should call your doctor straight away if you have any of these side effects.

There are other possible side effects where the frequency is not known and these effects include:

• depression
• erectile dysfunction
• flu-like symptoms
• migraine
• pancreatitis
• sensitivity to light
• urinary tract infections
• tinnitus
• changes to your taste

It is not known how often these side effects occur, but you should seek urgent medical help if you have any of them.

Long term side effects

Losartan can be taken safely for a long time, and is usually prescribed as a long-term medication as it is most effective when taken for a long period of time. Long-term use of losartan may affect how well your kidneys work, but your doctor will check regularly to make sure that it is safe for you to continue taking it.

Losartan and erectile dysfunction

Men with high blood pressure may experience erectile dysfunction. Studies suggest that losartan helps to resolve this problem by reducing your blood pressure. Having a healthy heart and blood vessels can improve your ability to get and maintain an erection.

Does losartan cause weight gain?

Weight gain is not listed as a side effect of taking losartan. But, if you are concerned that you are gaining weight after being prescribed losartan, you should speak to your doctor. Do not stop taking your medicine suddenly without talking to a doctor first, as this could increase the risk of having a heart attack or stroke.

What happens if I stop taking losartan?

If you stop taking losartan, you may see a rise in blood pressure which could increase the chance of a heart attack or stroke. You should not stop taking losartan without speaking with a doctor first, as they can advise you on how to safely stop taking this medication.

Usually, your doctor will gradually lower your dose to make sure your blood pressure is still being managed, and you may be prescribed another type of blood pressure medication which is more suitable for you.

Losartan and gout

Some research suggests that Losartan and other ARBs seem to reduce the level of uric acid in the body and may help to reduce the symptoms of gout.

Some other medicines might affect how well losartan works.

You should tell your doctor if you take any medications, including:

• other blood pressure medicines including enalapril, captopril, lisinopril or ramipril
• painkillers such as ibuprofen, naproxen, diclofenac, celecoxib or etoricoxib
• aspirin
• supplements or salt substitutes that contain potassium
• a blood-thinning medicine called heparin
• diuretics, tablets that make you pee more often
• lithium, used in the treatment of some mental health conditions
• spironolactone, used to treat heart failure

While there is not much information about taking losartan and herbal remedies together, you should also tell your doctor if you use any herbal treatments or supplements.

Losartan and painkillers

Losartan can interact with certain types of painkillers, so it’s important that you know which ones are safe to take. Paracetamol is considered to be safe to take with losartan, so that should be your go to option. You should avoid taking anti-inflammatory painkillers, such as ibuprofen, as they can raise your blood pressure and make losartan less effective. You should also be careful with aspirin, as it can reduce the effectiveness of losartan and may affect your kidney function. If you’re unsure, you can check in with a doctor to make sure the painkiller you want to take is safe.

Foods to avoid when taking losartan

You should not use substitutes for salt when taking losartan. These contain high levels of potassium and when taken with losartan they can make the level of potassium in your body too high. You should be able to eat a normal diet when taking losartan.

Losartan and coffee

Some studies suggest that coffee and losartan do not mix well. This is because caffeine can raise blood pressure. Decaffeinated coffee should be fine.

Losartan and grapefruit

Grapefruit and grapefruit juice may affect how well losartan works and it should be avoided if you are prescribed this medicine.

Losartan is one of several types of treatment for high blood pressure.

Alternative treatments include:

• other ARBs, including candesartan, irbesartan, valsartan
• calcium channel blockers – amlodipine
• ACE inhibitors – ramipril
• Beta-blockers
• diuretics like Bendroflumethiazide