Common questions about doxazosin

Doxazosin belongs to a group of medicines called alpha-adrenoceptor blocking drugs or alpha blockers.

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

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

Doxazosin is generally safe to take for a long time. In fact, it works best when you take it for a long time.

There are lots of other medicines to lower your blood pressure. They work in a different way from alpha blockers, and include:

• ACE inhibitors, such as ramipril
• angiotensin receptor blockers, such as candesartan
• calcium channel blockers, such as amlodipine
• diuretics (tablets that make you pee more), such as furosemide
• beta blockers, such as bisoprolol

Alpha blockers are not usually the first-choice treatment for high blood pressure.

The medicine your doctor prescribes depends on your age and ethnicity:

• if you're under 55, you'll usually be offered an ACE inhibitor or an angiotensin receptor blocker, unless you're of African Caribbean or Black African origin
• if you're 55 or older you'll usually be offered a calcium channel blocker
• if you're any age and of African Caribbean or Black African origin, you'll usually be offered a calcium channel blocker

Many people need to take a combination of different blood pressure-lowering tablets.

Tell your doctor if you're taking doxazosin and going to have cataract surgery. Your doctor may advise you to stop taking doxazosin 2 weeks before surgery.

This is because doxazosin may cause complications during the cataract operation.

If you're having other types of surgery, talk to your nurse or doctor at your pre-assessment appointment. They'll tell you if you need to stop taking doxazosin.

Some men taking doxazosin say they cannot get an erection. This is an uncommon side effect and will only affect up to 1 in 100 people.

Some men have also had long-lasting and painful erections. This is very rare, but if it does happen, contact a doctor straight away as it could cause tissue damage.

Some men have also reported little or no semen ejaculated during sex, or cloudy pee after sex. But this is not a common side effect and there's not enough evidence to say for sure that doxazosin is causing it.

Tell your doctor or pharmacist if you're taking medicines for erectile dysfunction, such as sildenafil, tadalafil or vardenafil.

If you take doxazosin with these medicines, you may feel dizzy or light-headed. You may be asked to leave a 6-hour gap between taking the doxazosin and any medicines for erectile dysfunction.

If you're having problems with your sex life, talk to your doctor.

You do not need to stop playing sports if you take doxazosin.

When you first start doxazosin, it may make you feel dizzy or weak. If this happens, it's best to sit or lie down until you feel better.

Regular exercise is good for you because it lowers blood pressure by keeping your heart and blood vessels in good condition.

Doxazosin will not stop your contraception working.

But some types of hormonal methods of contraception, such as the combined pill and contraceptive patch, are not usually recommended if you have high blood pressure.

Talk to your doctor if you're taking or using a combined hormonal contraceptive.

Doxazosin can make some people feel dizzy, especially when they first start taking it or after taking a bigger dose. If this happens to you, do not drive a car, ride a bike, or use tools or machinery until you feel OK again.

It's an offence to drive a car if your ability to drive safely is affected. It's your responsibility to decide if it's safe to drive. If you're in any doubt, do not drive.

Talk to your doctor or pharmacist if you're unsure whether it's safe for you to drive while taking doxazosin. GOV.UK has more information on the law on drugs and driving.

Drinking alcohol can increase the blood pressure-lowering effect of doxazosin, which can make you feel dizzy or light-headed.

During the first few days of taking doxazosin or after an increase in your dose, it's best to stop drinking alcohol until you see how the medicine affects you.

If you find taking doxazosin makes you feel dizzy, it's best to stop drinking alcohol.

You can eat and drink normally while taking doxazosin.

Eating a healthy, balanced diet can help if you have high blood pressure or a heart problem.

If you're taking doxazosin to treat high blood pressure, the following lifestyle changes can help:

• quit smoking
• cut down on alcohol
• exercise
• eat well
• manage stress
• vaccinations – if you have heart failure, it's recommended that you have the flu vaccine every year and the pneumococcal vaccine as recommended by your GP

If you're taking doxazosin to treat symptoms of an enlarged prostate gland, you might be able to relieve the symptoms by making some simple changes to your lifestyle:

• drink fewer fizzy drinks and less alcohol, and cut back on caffeine (like tea, coffee or cola) and artificial sweeteners – these can irritate the bladder and make peeing more uncomfortable
• drink less in the evening – try to reduce the amount you drink in the evening and avoid drinking anything for 2 hours before you go to bed. This might help you avoid getting up in the night. Make sure you're still drinking enough fluid earlier in the day
• empty your bladder – remember to go to the toilet before long journeys if you know you will not be able to reach a toilet easily
• try "double voiding" – this means waiting a few moments after you have finished peeing before trying to go again. It can help you empty your bladder properly. But take care not to strain or push
• check your medicines – check with your doctor whether any medicines you take, such as antidepressants or decongestants, may be making your symptoms worse
• eat more fruit and fibre – this will help you avoid constipation, which can put pressure on the bladder and make symptoms of an enlarged prostate worse