Experiences with
Olmesartan

Olmesartan is a medicine used to treat high blood pressure (hypertension).

It lowers your blood pressure and makes it easier for your heart to pump blood around your body.

Treating high blood pressure helps prevent future strokes, heart attacks and kidney problems.

It's only available on prescription and comes as tablets.

Dosage and strength

Olmesartan comes as 10mg, 20mg and 40mg tablets.

For adults and children aged 6 years and over, the usual starting dose is 10mg taken once a day.

Your dose may go up to 20mg or 40mg, taken once a day.

Children weighing less than 35kg (about 5.5 stone) should not take more than 20mg daily.

Changes to your dose

After a few weeks your doctor will check your blood pressure and ask you if you're getting any side effects.

You may also have blood tests to check how well your kidneys are working and the amount of potassium in your blood.

Your doctor will then decide whether to change your dose of olmesartan.

If olmesartan does not bring your blood pressure down, your doctor may want to increase the dose.

If your blood pressure gets too low or you get side effects, your doctor may want to lower your dose.

How to take it

Take olmesartan tablets once a day. Swallow the tablets whole with a drink of water. Do not crush or chew them.

You can take olmesartan with or without food.

Your doctor may suggest that you take your first dose before bedtime, as it can make you feel dizzy. After the first dose, you can then take olmesartan at any time of day.

Usually people take olmesartan in the morning, but it does not really matter. Just try to take it at the same time every day.

Speak to a pharmacist if you or your child have difficulty swallowing tablets.

How long to take it for

Usually treatment with olmesartan is long term, even for the rest of your life.

If you get ill while taking it

If you get severe diarrhoea or vomiting for any reason, contact your doctor or a pharmacist. They'll be able to advise you about what to do.

They may lower your dose or recommend that you stop taking olmesartan until you're better and able to eat and drink normally again.

If you take contraceptive pills and you're being sick (vomiting) or have severe diarrhoea for more than 24 hours, your contraception may not protect you from pregnancy. Check the pill packet to find out what to do.

If you forget to take it

If you miss a dose of olmesartan, take it as soon as you remember if it's the same day. If you do not remember until the next day, skip the forgotten dose and take your next dose at the usual time.

Do not 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.

Stopping olmesartan

Talk to your doctor if you want to stop taking olmesartan.

Stopping olmesartan may cause your blood pressure to rise. This may increase your chances of having a heart attack or stroke.

If you're bothered by side effects, your doctor may be able to prescribe a different blood pressure-lowering medicine.

Take olmesartan even if you feel well, as you'll still be getting the benefits of the medicine.

Taking too much olmesartan can make you feel dizzy (due to low blood pressure).

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

you take more than your prescribed dose of olmesartan

Go to 111.nhs.uk or call 111 .

If you need to go to A&E, do not drive. Ask someone to drive you or call 999 and ask for an ambulance.

Bring the olmesartan packet or leaflet inside it, any remaining medicine, and any other medicines you take.

Who can take olmesartan

Most adults, and children aged 6 years and over, can take olmesartan.

Who may not be able to take olmesartan

Olmesartan is not suitable for some people. To make sure it's safe for you, tell your doctor if you:

have ever had an allergic reaction to olmesartan or any other medicine
have bile duct or gallbladder problems, such as blocked bile ducts or gallstones
have diabetes
have heart, liver or kidney problems, or have recently had a kidney transplant
have recently had severe diarrhoea or you're being sick (vomiting)
have ever been on a low-salt diet
have low blood pressure (hypotension)
are trying to get pregnant, are already pregnant or you're breastfeeding

Common side effects

These common side effects of olmesartan happen in more than 1 in 100 people.

There are things you can do to help cope with them:

If olmesartan makes you feel dizzy when you stand up, try getting up very slowly or stay sitting down until you feel better. If you begin to feel dizzy, lie down so you do not faint, then sit until you feel better.

Do not drive, ride a bike or use tools or machines if you feel dizzy.

Rest and drink plenty of fluids. Do not drink too much alcohol if you get headaches. Take paracetamol if you need to, or ask your pharmacist to recommend a painkiller.

Talk to your doctor if these side effects last longer than a week or are severe.

Take paracetamol if you need to, or ask your pharmacist to recommend a painkiller. Talk to your doctor if these side effects last longer than a week or are severe.

Try taking your tablets with or after a meal or snack. Take small, frequent sips of water or squash to prevent dehydration. It may also help if you do not eat rich or spicy food.

Talk to a pharmacist before taking indigestion remedies like antacids, as some of them can stop olmesartan working properly.

Try to rest and relax. It can help to eat and drink slowly and have smaller and more frequent meals.

Putting a heat pad or covered hot water bottle on your stomach may also help. If you are in a lot of pain, speak to your pharmacist or doctor.

Drink plenty of water or squash to prevent dehydration. Signs of dehydration include peeing less than usual or having dark, strong-smelling pee.

If you get severe diarrhoea or vomiting from a stomach bug or illness, tell your doctor. You may need to stop taking olmesartan for a while until you feel better. Speak to a pharmacist before taking any medicine to treat diarrhoea.

If you take the combined pill or progestogen-only pill and you have severe diarrhoea for more than 24 hours, your contraception may not protect you from pregnancy. Check the pill packet for advice.

Raise your legs when you're sitting down.

Contact your doctor if you have symptoms of a UTI as you may need treatment. Symptoms include needing to pee suddenly or more often, pain when peeing, smelly or cloudy pee, or pain in your lower belly.

Drink plenty of water and take paracetamol to ease the pain if you need to.

Ask for an urgent doctor's appointment if you also have pain in your sides or lower back, have a very high temperature or feel hot and shivery, have diarrhoea, or are feeling or being sick.

Talk to your doctor or pharmacist if the advice on how to cope does not help and these side effects bother you or do not go away.

Serious side effects

Some people have serious side effects after taking olmesartan.

Call a doctor or call 111 straight away if you have:

blood in your pee
severe diarrhoea that does not go away and causes noticeable weight loss
a rash or tiny reddish-purple spots under the skin (this may be less obvious on black or brown skin), cuts that will not stop bleeding, unexplained bruising, bleeding gums, nosebleeds or unusually heavy periods
weak muscles, numbness or tingling, an irregular heartbeat or palpitations, and feeling sick and short of breath – these can be signs of high levels of potassium in your blood

you get chest pain that does not stop after a few minutes – chest pain is a possible sign of a heart attack and needs to be checked as soon as possible

A&E safety messaging (for 999 only)

In rare cases, it's possible to have a serious allergic reaction (anaphylaxis) to olmesartan.

Meds New IA (H4) - serious allergic reaction

Taking olmesartan for a long time can sometimes cause your kidneys not to work as well as they should. Your doctor will check how well your kidneys are working with regular blood tests.

Other side effects

These are not all the side effects of olmesartan. For a full list, see the leaflet inside your medicines packet.

Olmesartan and pregnancy

Olmesartan is not recommended in pregnancy. It can reduce the level of fluid around your baby, particularly if you take it in the second and third trimesters of pregnancy. This can result in long-term damage to your baby's kidneys and lungs as well as other problems.

It's best to stop taking olmesartan before getting pregnant, but you may be able to keep taking it until you have a positive pregnancy test and then stop. Your doctor will discuss what's best for you, based on your condition and the risks and benefits of olmesartan.

If you're already pregnant, stop taking olmesartan and talk to your doctor straight away. Usually your doctor will be able to prescribe a different medicine that is safer to take in pregnancy. Olmesartan should be stopped by the time you're 12 weeks pregnant.

It's important to use contraception if you're taking olmesartan and plan any pregnancy with your doctor or specialist carefully. They will review your condition and medicine before you get pregnant.

Olmesartan and breastfeeding

It may be OK to take olmesartan while breastfeeding, but talk to your doctor or pharmacist first. It's best not to take olmesartan if your baby was born prematurely, but your doctor will help you decide.

It's not yet known how much olmesartan gets into breast milk. There is a very small risk that it could also lower your baby's blood pressure. Until we know more about olmesartan in breastfeeding, your doctor may recommend a different medicine for you to take.

Talk to your health visitor, midwife, pharmacist or doctor if:

your baby is not feeding as well as usual
your baby seems unusually sleepy
your baby looks much paler than normal
you have any other concerns about your baby

Olmesartan and fertility

There's no evidence that olmesartan reduces fertility in men or women.

But speak to a pharmacist or your doctor before taking it if you're trying to get pregnant.

Meds New IA (H2) - Pregnancy non-urgent care card

Cautions with other medicines

There are some medicines that do not mix well with olmesartan.

Before starting olmesartan, tell your doctor if you're taking:

other medicines to help lower your blood pressure, especially aliskiren or an ACE inhibitor, such as enalapril, captopril, lisinopril or ramipril
non-steroidal anti-inflammatory drugs (NSAIDs) such as ibuprofen, naproxen, diclofenac, celecoxib or aspirin for pain relief
tablets to make you pee more (diuretics) such as furosemide, bendroflumethiazide or indapamide
lithium, a medicine for mental health problems
heparin, a medicine that treats or prevents blood clots
spironolactone, a medicine to treat heart failure
colesevelam, a medicine for lowering cholesterol

Mixing olmesartan with herbal remedies or supplements

Tell your pharmacist or doctor if you're taking potassium supplements or salt substitutes which contain potassium

There's very little information about taking other herbal remedies and supplements with olmesartan. They're not tested in the same way as prescription medicines.

Meds New IA (H2) - Cautions with other medicines alert