What doxazosin is for

Doxazosin is used to:

lower high blood pressure (hypertension), which can reduce the risk of heart attack and stroke
treat the symptoms of an enlarged prostate, such as problems with peeing

Doxazosin is a type of medicine called an alpha blocker.

It works by widening your blood vessels, making it easier for blood to move around your body. It also relaxes the muscles around the prostate and bladder, which can make it easier to pee.

How to take doxazosin

Doxazosin comes as a tablet that you swallow.

You'll usually need to take it once a day, at the same time every day, with a drink of water.

Your doctor will tell you how much to take and for how long. Doxazosin treatment is often long term, and you'll probably need to take it for several years

Always check the packet or leaflet that comes with your medicine. Ask a pharmacist or doctor for advice if you're not sure how to take it or have any problems taking it.

If you miss a dose of doxazosin

If you miss a dose of doxazosin, take it as soon as you remember, unless it's nearly time for your next dose.

If it's nearly time for your next dose, skip the dose you missed and take your next dose at the usual time.

Do not take 2 doses to make up for a missed dose.

If you take too much doxazosin

Taking an extra dose of doxazosin can be be dangerous.

Urgent advice: Call NHS 111 if:

you've taken more than your prescribed dose of doxazosin

If you're told 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.

Side effects of doxazosin

Like all medicines, doxazosin can cause side effects, although not everyone gets them.

Common side effects

Common side effects of doxazosin include:

headaches, dizziness and feeling like everything around you is spinning (vertigo)
swelling, usually in your ankles, feet and legs (oedema)
cold-like symptoms, such as sneezing, or flu-like symptoms, such as a high temperature and an aching body
tummy pain
feeling sick (nausea) and being sick (vomiting)

If you feel dizzy or get vertigo after taking doxazosin, do not drive, ride a bike or use machinery until you no longer have these symptoms.

Non-urgent advice: Speak to a pharmacist or doctor if:

you have any side effects that bother you or do not go away

They may be able to give you advice about how to reduce any side effects. Keep taking your medicine unless you're advised to stop.

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Serious side effects

Doxazosin can sometimes cause serious side effects, although most of them are rare.

Possible serious side effects of doxazosin include:

a severe allergic reaction (anaphylaxis) – causing symptoms such as a swollen throat or tongue, a raised, itchy rash and difficulty breathing
a painful erection that does not go away (priapism)
a stroke – causing symptoms such as your face drooping on one side, not being able to hold both arms up and difficulty speaking
a heart attack – causing symptoms such as chest pain, and pressure, heaviness, tightness or squeezing across the chest

Immediate action required: Call 999 if:

you're taking doxazosin and think you're having anaphylaxis, priapism, stroke or heart attack

If you think you're having any other serious side effects, call NHS 111.

More about side effects

These are not all the side effects of doxazosin.

For a full list, see the leaflet inside your medicines packet, or search for your medicine leaflet on the electronic medicines compendium website.

You can report any side effects you get on the Yellow Card Scheme website

Who can and cannot take doxazosin

Most adults can take doxazosin. It may also be given by a specialist to children to treat high blood pressure or bladder problems.

Doxazosin is not suitable for everyone. For example, it may not be suitable if:

you've had an allergic reaction or serious side effects from doxazosin
you have an enlarged prostate and low blood pressure
you have an enlarged prostate and bladder or kidney problems
you've been told you have orthostatic hypotension (you get dizzy and light-headed when you stand up)

Before taking doxazosin, tell your doctor or a pharmacist if you have any medical conditions.

Breastfeeding and doxazosin

Tell your doctor if you're breastfeeding.

Doxazosin passes into breast milk in very small amounts. A doctor may recommend you breastfeed if the benefits outweigh the risks.

If you're taking doxazosin while breastfeeding, speak to a healthcare professional or call NHS 111 if you have any concerns about your baby.

Pregnancy and doxazosin

Tell your doctor if you're pregnant. Doxazosin is not usually used during pregnancy as not enough is known about its safety.

But a doctor may recommend it if the benefits outweigh the risks.

Taking doxazosin with other medicines, food and drink

There are some medicines, remedies and supplements that may not mix well with doxazosin.

These include:

medicines to treat erectile dysfunction, like sildenafil (Viagra)
clarithromycin – an antibiotic often used to treat chest infections and skin infections
some other blood pressure medicines
medicines to treat fungal infections
medicines to treat HIV

Before taking doxazosin, tell your doctor if you're taking any other medicines, herbal remedies, vitamins or supplements.

Food and alcohol with doxazosin

You can eat as normal while taking doxazosin, but it's best not to drink alcohol while taking doxazosin as this can raise the risks of side effects.

Find out more about your medicine

To find out more about your medicine, you can:

check the leaflet that comes with it
search for your medicine leaflet on the electronic medicines compendium website
speak to a pharmacist or doctor for advice – if you recently started taking it, you can get help with newly prescribed medicines from a pharmacist as part of the New Medicine Service