Doxazosin is a treatment for high blood pressure (hypertension). It belongs to a group of medicines called alpha blockers, which can relax your blood vessels. This makes it easier for your heart to pump blood around your body, lowering your blood pressure.
Doxazosin is a generic medication containing the active ingredient, doxazosin (as mesilate). The starting dose is 1mg daily, which can be increased up to 16mg to treat high blood pressure. It should be taken every day for the best effect.
If you have high blood pressure, you can get doxazosin through our online service without waiting for a GP appointment. Complete a short medical questionnaire which is reviewed by one of our doctors. The treatment will be prescribed to you, if it is suitable. Your treatment can then be delivered straight to your front door, with no delivery fees.
3 x 28 tablet(s) - £19.00
6 x 28 tablet(s) - £27.00
3 x 28 tablet(s) - £20.00
6 x 28 tablet(s) - £29.00
3 x 28 tablet(s) - £21.00
6 x 28 tablet(s) - £31.00
Doxazosin is used for the treatment of high blood pressure, also known as hypertension. Doxazosin is an alpha-blocker and can lower your blood pressure by relaxing your blood vessels, making it easier for blood to flow around your body. Doxazosin is prescribed once daily with doses rangingbetween 1mg and 16mg, depending on your blood pressure.
Doxazosin should be taken once a day, either in the morning or evening. It must be taken at the same time every day to get the best effect. The tablets can be taken with or without food. Take the tablets whole, with a full glass of water.
The starting dose is 1mg, once a day. Once your body gets used to the treatment, your doctor will increase the dose as required. The usual dose is between 2 and 4mg once a day. The maximum daily dose is 16mg. Doxazosin will work as long as it is taken. This means you should not stop taking it unless you speak to your doctor.
Avoid drinking alcohol with this medication until you get used to the treatment. Doxazosin and alcohol can both cause your blood pressure to get lower, which may cause side effects like dizziness. If taking doxazosin makes you dizzy, you should avoid alcohol while you are on this medication.
Doxazosin belongs to a group of medications called alpha-blockers, or alpha adrenoceptor blocking drugs. They prevent a hormone called norepinephrine from narrowing the muscles surrounding your blood vessels. Doxazosin can help your blood vessels relax and widen, making it easier for your heart to pump blood through your body. This will lower your blood pressure. You must continue taking doxazosin every day for it to lower your blood pressure.
Doxazosin has been found to be effective in controlling blood pressure in 76% of patients. Some people may need more than one type of blood pressure medication to lower blood pressure.
Doxazosin must be taken every day to get the best effect. You may start to notice a change within 2 to 3 hours of taking it, but the best effects will be achieved after taking it for a few weeks. You can take doxazosin for as long as needed to control your blood pressure.
Doxazosin, like other medications, may have some side effects. Not everybody that takes it will get them and most will go away once you get used to the treatment. If you get any side effects that worry you or do not go away after a few weeks, speak to your doctor.
Speak to your doctor straight away if you get:
- changes to your heartbeat, such as palpitations, increased heart rate, or irregular heartbeat
- shortness of breath or difficulty breathing
- chest pain or angina
- yellowing of your skin or the whites of your eyes (jaundice)
- unexplained bruising, easy bleeding, or increased infections, as this may be a sign of low white blood cells
Common side effects include:
- low blood pressure
- nose, throat, or lung infections
- swelling of your feet, ankles, or fingers
- runny nose
- stomach pain
- nausea or vomiting (feeling or being sick)
- problems with your bladder, such as urinary tract infections (UTIs) or inflammation
- back pain
- flu like symptoms
Uncommon side effects include:
- constipation or diarrhoea
- inflammation of your joints
- swelling of your face
- changes in mood
- reduced sense of touch
- weight gain, increased appetite, or loss of appetite
- skin rash
- nose bleeds
- ringing in your ears
- erectile dysfunction
You must stop taking doxazosin and call 999 straight away if you get any symptoms of a heart attack, stroke, or a persistent painful erection of the penis.
There are some rare side effects from doxazosin. The patient information leaflet that’s included with your medication should explain these. Make sure you read this.
Doxazosin is suitable for adults who have high blood pressure.
It may not be suitable if you:
- are pregnant or breastfeeding
- have orthostatic hypotension, which is a type of low blood pressure
- are allergic to doxazosin, or other ingredients in the tablets
- are due to have surgery for cataracts
- have an enlarged prostate and low blood pressure, bladder stones, or a blockage in your urinary tract
- do not feel the urge to pee, or your body is not producing pee
- have an enlarged prostate gland and faint during or after peeing
If any of the above are relevant to you, or you have any other health conditions, speak to your doctor before taking doxazosin.
Doxazosin is safe to take with many medicines but may not be suitable if you also take:
- erectile dysfunction treatment
- ketoconazole, which is a medication for fungal infections
- other medicines for high or low blood pressure
Anti inflammatory medications, such as ibuprofen, can increase your blood pressure. Your doctor may tell you to stop taking them or to reduce how much you take alongside doxazosin. Speak to your doctor if you take any other medications.
If doxazosin is not suitable for you, there are alternative treatments available through our service. These include:
- beta-blockers, such as bisoprolol
- diuretics (water tablets), such as bendroflumethiazide
- angiotensin II receptor antagonists, such as losartan or irbesartan
- ACE inhibitors, such as lisinopril, ramipril, or enalapril
You should not stop taking doxazosin, even when you feel better. If you stop taking it, your blood pressure will increase again. Speak to your doctor if you want to stop taking doxazosin. Doxazosin is safe to be taken over a long period.
If you forget a dose, wait until your next dose is due and continue taking doxazosin as prescribed. Never take 2 tablets at once to make up for a forgotten dose.
If you take more doxazosin than prescribed, it could lower your blood pressure too much. You may get side effects such as an increased heart rate, drowsiness, and lightheadedness. Speak to your doctor or visit A&E, if you take too much doxazosin (take your tablet pack with you).
Doxazosin is also used in the treatment of an enlarged prostate, which is known as benign prostatic enlargement. However, we only prescribe doxazosin for the treatment of high blood pressure.
Dr Babak Ashrafi Clinical Lead for Service Expansion
Babak studied medicine at King’s College London and graduated in 2003, having also gained a bachelor’s degree in Physiology during his time there. He completed his general practice (GP) training in East London, where he worked for a number of years as a partner at a large inner-city GP practice. He completed the Royal College of GPs membership exam in 2007.Meet our doctors
Last reviewed: 13 Jan 2022
Benign prostate enlargement (2020) NHS (accessed 05 December 2021)
Doxazosin (2019) NHS (accessed 05 December 2021)
Doxazosin 1mg, 2mg, 4mg Tablets (2020) EMC (accessed 05 December 2021)
Efficacy and safety of doxazosin in hypertension therapy (1987) PubMed (accessed 05 December 2021)
High blood pressure (hypertension) (2019) NHS (accessed 05 December 2021)