Experiences with
Doxazosin

Doxazosin belongs to a group of medicines called alpha blockers.

It's used to treat high blood pressure (hypertension) and symptoms of an enlarged prostate (benign prostatic enlargement).

Alpha blockers reduce blood pressure by relaxing your blood vessels so blood can pass through them more easily.

Doxazosin helps to reduce the symptoms of an enlarged prostate gland by relaxing the muscle around the bladder and prostate gland so you can pee more easily.

This medicine is only available on prescription and comes as tablets.

Who can take doxazosin

Most adults aged 18 years and over can take doxazosin.

This medicine is not usually prescribed for children under the age of 18 years, unless a specialist children's doctor prescribes it.

Who may not be able to take doxazosin

Doxazosin is not suitable for some people. To make sure this medicine is safe for you, tell your doctor if you:

have ever had an allergic reaction to doxazosin or other similar medicines, such as alfuzosin, prozosin, tamsulosin or terazosin
are pregnant, breastfeeding or trying to get pregnant
have orthostatic hypotension – a type of low blood pressure that can make you feel dizzy or light-headed when you stand up
have an enlarged prostate gland and low blood pressure (hypotension)
have an enlarged prostate gland and bladder stones or a blockage or longstanding infection in your urinary tract
have an enlarged prostate gland and you faint when peeing or shortly after peeing
do not feel the urge to pee or your body is not producing any pee
are due to have cataract surgery

Dosage and strength

Standard doxazosin tablets come as 1mg, 2mg, 4mg and 8mg strengths.

Slow-release tablets come as 4mg and 8mg strengths.

How much you take depends on why you need doxazosin and the type of tablet you're taking.

The usual dose for high blood pressure is:

standard tablets – 2mg to 16mg, taken once a day
slow-release tablets – 4mg or 8mg, taken once a day

The usual dose for an enlarged prostate gland is:

standard tablets – 2mg to 8mg, taken once a day
slow-release tablets – 4mg or 8mg, taken once a day

You may have to take more than 1 tablet to make up your dose (for example, 2 of the 8mg tablets to make up a 16mg dose). Your doctor will tell you how many tablets to take each day.

Changes to your dose

Your doctor will start you on a lower dose.

If you're taking standard tablets, your doctor will usually start you on 1mg. They will gradually increase your dose until your condition is under control.

With slow-release tablets, your doctor will usually start you on 4mg and this may be increased to 8mg.

How to take it

Take your doxazosin tablets with a glass of water. Swallow them whole. Do not chew them.

You can take both types of tablet with or without food.

You can take doxazosin in the morning or evening, but it's best to take it at the same time each day.

Some standard tablets have a score line to help you break the tablet and make it easier to swallow. Check your medicine's information leaflet to see if you can do this.

How long to take it for

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

Talk to your doctor if you want to stop taking doxazosin. Suddenly stopping can make your condition worse.

If you are bothered by side effects, your doctor may be able to prescribe a different medicine for your blood pressure or enlarged prostate.

Once you've stopped, it'll take 4 to 5 days for it to be completely out of your body.

If you forget to take it

If you miss a dose of doxazosin, skip the missed dose. Take the next dose at the usual time. Do not take 2 doses to make up for a forgotten dose.

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.

If you take too much

Taking too much doxazosin can reduce your blood pressure and increase your heart rate.

you take more than your prescribed dose of doxazosin and feel drowsy, faint or light-headed

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 doxazosin packet or leaflet inside it, any remaining medicine, and any other medicines you take.

Common side effects

These common side effects of doxazosin happen in more than 1 in 100 people. They're usually mild and only last a short time. There are things you can do to help cope with them:

If doxazosin makes you feel weak, sleepy, dizzy, or like everything around you is spinning (vertigo), stop what you're doing and sit or lie down until you feel better. Do not drive, cycle or use tools or machinery. It's best not to drink alcohol, as it will make you feel worse. If you feel sleepy, it may help to take your medicine at night time.

If you're still feeling dizzy after a week, or all of the time, speak to your doctor.

Make sure you rest and drink plenty of fluids. Do not drink too much alcohol. Ask your pharmacist to recommend a painkiller.

Talk to your doctor if the headaches are severe or last longer than a few days.

Raise your legs, or the swollen area, onto a chair or pillows when you can.

Contact your doctor if you have symptoms of a UTI as you may need treatment. Symptoms can include needing to pee suddenly or more often than usual, pain or a burning sensation when peeing, and smelly or cloudy pee.

Rest and drink plenty of fluids. This helps your body to flush out bacteria.

Try to rest and relax. It can help to eat and drink slowly, and have smaller and more frequent meals. Take a painkiller like paracetamol. Place a hot water bottle on your stomach or back, or between your thighs.

If you're in a lot of pain, speak to your pharmacist or doctor.

Stick to simple meals and avoid rich or spicy food. It might help to take your doxazosin after you have eaten. Drink plenty of water or other fluids to avoid dehydration. If you're feeling sick, take small, frequent sips.

Talk to your doctor or pharmacist if this advice does not help or the side effects last more than a few days:

Serious side effects

Call your doctor or call 111 now if:

the whites of your eyes turn yellow, or your skin turns yellow although this can be harder to see on brown and black skin – these can be signs of liver problems
you get unexplained bruising or bleed easily – these can be signs of a blood problem

you get chest pain, an irregular heartbeat or you can feel your heartbeat (palpitations) – these can be signs of heart problems

A&E safety messaging (for 999 only)

weak arms or legs or problems speaking – these can be signs of a stroke
a painful erection that lasts 2 or more hours
shortness of breath or difficulty breathing – these can be signs of lung problems

In rare cases, doxazosin may cause a serious allergic reaction (anaphylaxis).

Meds New IA (H4) - serious allergic reaction

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

Doxazosin and pregnancy

Doxazosin is not recommended in pregnancy because there is little information on whether it may affect the developing baby.

If you have high blood pressure your doctor will be able to suggest a different medicine that can be used in pregnancy.

If you're trying to get pregnant or already are pregnant, talk to your doctor about the benefits and possible harms of taking doxazosin.

Doxazosin and breastfeeding

If your doctor or health visitor says your baby is healthy, it's OK to take doxazosin while you're breastfeeding, but talk to your doctor or pharmacist first. They may recommend a different medicine for your blood pressure that we know a bit more about.

Doxazosin passes into breast milk in tiny amounts and it is unlikely to cause any side effects in your baby.

If you notice that your baby is not feeding as well as usual, seems unusually sleepy, looks much paler than usual, or if you have any other concerns about your baby, then talk to your health visitor, midwife, pharmacist or doctor as soon as possible.

Doxazosin and fertility

There's no evidence to suggest that taking doxazosin reduces fertility in either 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 can affect the way doxazosin works.

Tell your doctor or pharmacist if you're taking:

medicines for erectile dysfunction, such as sildenafil, tadalafil or vardenafil
other medicines for high blood pressure – when taking doxazosin they can sometimes lower your blood pressure too much
other medicines that can lower your blood pressure – this includes some antidepressants, muscle relaxants like baclofen, medicines for chest pain like nitrates, and medicines for Parkinson's disease like co-careldopa or levodopa
ketoconazole, a medicine usually used for fungal infections

Taking doxazosin with painkillers

Non-steroidal anti-inflammatory drugs (NSAIDs), such as ibuprofen, may increase your blood pressure, so it's best to keep them to a minimum.

You can take paracetamol or codeine safely with doxazosin.

Mixing doxazosin with herbal remedies and supplements

There's not enough information to say that herbal remedies and supplements are safe to take with doxazosin. They're not tested in the same way as pharmacy and prescription medicines. They're generally not tested for the effect they have on other medicines.

OLD Meds - Cautions with other medicines alert