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Prazosin

  • Take your first dose of prazosin at bedtime. If you feel dizzy, faint, tired or are sweating, lie down until the feeling passes.
  • As your body is getting used to prazosin you may feel dizzy or light-headed when standing up or sitting up quickly - getting up more slowly will help.

About prazosin

Type of medicine Alpha-blocker
Used for Hypertension (high blood pressure)
Heart failure (a condition where the pumping action of the heart is reduced)
Raynaud's syndrome (circulation problems)
Enlargement of the prostate gland in men
Also called Hypovase®
Available as Tablets

Prazosin works in high blood pressure, heart failure and Raynaud's disease by relaxing the blood vessels. This allows blood and oxygen to circulate more freely around the body, lowering blood pressure and reducing the strain on the heart.

In patients with Raynaud's disease, prazosin relaxes the blood vessels in the hands so that blood can reach the fingers more easily. This helps to prevent coldness and stiffness.

Enlargement of the prostate gland can reduce the flow of urine from the bladder and it can also lead to other urinary problems. Prazosin relaxes muscles around the bladder and prostate so that urine can be passed more easily.

Before taking prazosin

Before taking prazosin make sure your doctor or pharmacist knows:

  • If you are pregnant, trying for a baby or breast-feeding.
  • If you suffer from liver or kidney problems.
  • If you have ever fainted after passing urine.
  • If you feel dizzy or faint when standing up from a sitting or lying position.
  • If you have heart failure that is because of another heart condition.
  • If you have ever had an allergic reaction to this or any other medicine.
  • If you are taking any other medicines, including those available to buy without a prescription, herbal or complementary medicines.

How to take prazosin

  • Take this medicine exactly as directed by your doctor.
  • If you are taking prazosin for the first time, take your very first dose at bedtime. Prazosin can make you faint or feel faint when taken for the first time.
  • Try to take this medicine at the same times each day to avoid missing any doses.
  • If you forget to take a dose, leave out the missed dose and take the next dose on time.
  • Do not stop taking prazosin without consulting your doctor first.
  • Never take more than the prescribed dose. If you suspect that you or someone else has taken an overdose of prazosin, contact your doctor or go to the accident and emergency department of your local hospital at once. Where possible take the container with you even if it is empty.
  • This medicine is for you. Never give it to others even if their condition appears to be the same as yours.

Getting the most from your treatment

  • Prazosin can cause dizziness and drowsiness particularly when you first start taking it. Make sure your reactions are normal before driving, operating machinery or doing any other jobs which could be dangerous if you were not fully alert.
  • Before taking any 'over-the-counter' medicines, check with your pharmacist which medicines are safe for you to take alongside prazosin.
  • Before having any kind of surgery, including dental or emergency treatment, tell your doctor, dentist or surgeon you are taking prazosin. This is particularly important if you are having eye surgery whilst taking prazosin.

Can prazosin cause problems

Along with their useful effects all medicines can cause unwanted side effects, which usually improve as your body adjusts to the new medicine. Speak with your doctor or pharmacist if any of the following side effects continue or become troublesome.

Common side-effects - these affect less than 1 in 10 people who take this medicine What can I do if I experience this
Feeling or being sick, diarrhoea Eat little and often. Stick to simple foods such as dry toast and drink plenty of water to replace any lost fluids
Dizziness, light-headedness or fainting, especially when getting up from a lying or sitting position Getting up slowly may help. If you begin to feel dizzy, lie down so that you do not faint, then sit for a few moments before standing to prevent the dizziness returning
Drowsiness, blurred vision Make sure your reactions are normal before driving, operating machinery or doing any other jobs which could be dangerous if you were not fully alert or could not see clearly
Headache Ask your pharmacist to recommend a suitable pain-killer. If the headache continues, speak with your doctor

Other possible side-effects include; swelling of the lower legs and feet, racing heart beat, a feeling of it being difficult to breathe, stuffy nose, mood changes, weakness and wanting to pass water more often.

How to store prazosin

  • Keep all medicines out of the reach of children.
  • Store in a cool, dry place, away from direct heat and light.
  • Never keep out of date or unwanted medicines. Take them to your local pharmacy which will dispose of them for you.

Important information about all medicines


  • Keep all medicines out of the sight and reach of children.
  • Make sure that the person prescribing this medicine knows about any other medicines that you are taking. This includes medicines you buy and herbal and homeopathic medicines.
  • If you buy any medicines check with a pharmacist that they are safe to take with your other medicines.
  • Before taking this medicine tell your doctor if you have ever had an allergic reaction after taking any medicine.
  • Never take more than the prescribed dose. If you suspect that you or someone else has taken an overdose of this medicine go to the accident and emergency department of your local hospital at once. Where possible take the container with you, even if it is empty.
  • If you are having any treatment like an operation or dental treatment tell the person carrying out the treatment which medicines you are taking.
  • Always read the printed information leaflet that comes with your medicine.
  • This medicine is for you. Never give it to other people even if their condition appears to be the same as yours.
  • Never keep out of date or unwanted medicines. Take them to your local pharmacy which will dispose of them for you.
  • If you have any questions about this medicine ask your pharmacist.

References

  • British National Formulary; 54th Edition (September 2007) British Medical Association and Royal Pharmaceutical Society of Great Britain, London (link to current BNF).
  • Manufacturer's PIL, Hypovase® Pfizer Limited, electronic Medicines Compendium. Dated August 2007, accessed 21 December 2007.
© EMIS 2008 DocID:
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dils2094		 Last Updated:
4 Feb 2008		 Date of Next Review:
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PS - Health and Poverty

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See also MAKEPOVERTYHISTORY North East for details and links to campaigns against poverty.

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