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How and when to take doxazosin

Doxazosin comes as 2 different types of tablet, standard and slow-release. Slow-release tablets release the doxazosin gradually.

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.

Urgent advice: Contact 111 for advice now if:

  • 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 yourself. Get someone else to drive you, or call an ambulance.

Take the doxazosin packet, or the leaflet inside it, with you, plus any remaining medicine.

Page last reviewed: 2 March 2022
Next review due: 2 March 2025