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PRAZOSIN 0.5 mg AND 1 mg



have previously used Prazosin. This is because Prazosin
may cause complications during the surgery which can
be managed if your specialist is prepared in advance.

Some patients who take Prazosin for the treatment of
high blood pressure or prostate enlargement may
Read all of this leaflet carefully before
experience dizziness or light-headedness, which may
you start taking this medicine.
be caused by low blood pressure upon sitting or
• Keep this leaflet. You may need to
standing up quickly. Certain patients have experienced
read it again.
these symptoms when taking drugs for erectile
• If you have any further questions, ask dysfunction (impotence) with Prazosin. In order to
your doctor or pharmacist.
reduce the likelihood that these symptoms occur, you
• This medicine has been prescribed
for you. Do not pass it on to others. It should be on a regular daily dose of Prazosin before
you start drugs for erectile dysfunction.
may harm them, even if their
symptoms are the same as yours.
If you have any tests, such as blood or urine tests, make
• If any of the side effects get serious,
sure that the doctor or nurse knows that you are taking
or if you notice any side effects not
Prazosin, as it can affect the results of some tests.
listed in this leaflet, please tell your
Taking other medicines
doctor or pharmacist.
Talk to your doctor if you are taking any of the
1. What Prazosin is and what it is used for • thiazide diuretics (water tablets) e.g.
2. Before you take Prazosin
3. How to take Prazosin
• calcium antagonists (e.g. diltiazem) or beta
4. Possible side effects
blockers (e.g. propranolol)
5. How to store Prazosin
• medicines for erectile dysfunction (impotence, e.g.
6. Further information
sildenafil, tadalafil).
Please tell your doctor or pharmacist if you are taking
or have recently taken any other medicines, including
medicines obtained without a prescription.
Your tablets are called Prazosin Tablets. Important information about some of the ingredients
They are part of a group of drugs
of Prazosin
known as alpha-adrenoceptor blocking • Patients who are intolerant to lactose should note
drugs (alpha-blockers).
that Prazosin tablets contain a small amount of
Prazosin is used:
lactose. If your doctor has told you that you have
• in the treatment of high blood
an intolerance to some sugars, contact your doctor
pressure (hypertension) by widening
before taking this medicine
the blood vessels and lowering the blood pressure
• in the treatment of heart failure, a condition where • The 1 mg tablets contain dispersed orange (E110) as
a colouring agent. E110 may cause possible allergic
the heart’s pumping action is not strong enough and
reactions, including asthma. If you are allergic to
leads to a build-up of fluid in the lungs and tissues
aspirin, you are more likely to suffer a reaction.
• in the symptomatic treatment of Raynaud’s disease
(painful cold fingers) by relaxing the blood vessels Pregnancy and breast-feeding
in the hands and feet so blood can reach your
• If you are pregnant, planning to become pregnant
hands and feet more easily. This helps to prevent
or breast-feeding, ask your doctor for advice before
coldness and stiffness
taking this medicine.
• in the symptomatic treatment of Prostatic
Hyperplasia in men (mild enlargement of the
Driving and using machines
prostate gland) to relieve poor and/or frequent
• When you first start taking Prazosin you may feel
passing of urine. This works by relaxing the muscle
dizzy, weak, drowsy or have blurred vision. If you
around the bladder and prostate gland so that you
are affected, DO NOT drive or operate machinery.
can pass urine more easily.



DO NOT take Prazosin if you:
• are allergic (hypersensitive) to Prazosin, other
similar drugs known as quinazolines e.g. doxazosin
or any of the other ingredients of this medicine
• have congestive heart failure (condition in which
the heart is not strong enough to pump blood
efficiently around the body so fluid collects in the
lungs and body tissue and causes congestion)
caused by mechanical obstruction e.g. aortic
stenosis (narrowing of the aortic valve in the heart).
Take special care with Prazosin
Some patients will feel faint or collapse after the first
dose of Prazosin Tablets and if this happens you
should lie down for a while. Please bear this in mind
when you start to take your tablets.



Always take Prazosin exactly as your doctor has told
you. You should check with your doctor or pharmacist
if you are not sure.
The tablets should be swallowed preferably with a
drink of water. The usual dose is:
• High Blood Pressure
The recommended starting dose is 0.5 mg 2-3
times daily for the first 3-7 days. The first dose
should be taken in the evening.
The dose is usually increased to 1 mg 2-3 times
daily for a further 3-7 days.
Your doctor may then gradually increase this dose
to a maximum of 20 mg a day depending on how
you have responded to treatment.
Your medicine can be taken when taking other
medicines for hypertension. Your doctor will adjust
your dose accordingly.

Tell your doctor before you start to take this
medicine if you:
• have an enlarged prostate
• have had heart failure due to a recent heart attack
• Congestive heart failure
• have had a recent pulmonary embolism (breathing
The recommended starting dose is 0.5 mg, 2-4 times
difficulty due to a blood clot in the lungs)
daily. The first dose should be taken in the evening.
• have ever fainted after passing urine
The dose is usually increased gradually to 4 mg
• have kidney or liver failure
daily in divided doses. Your doctor may then
• are to have cataract surgery on your eye.
gradually increase this dose to a maximum of 20 mg
If you are undergoing eye surgery because of cataract
a day depending on how you have responded to
(cloudiness of the lens) please inform your eye
specialist before the operation that you are using or

• Raynaud’s disease
The recommended starting dose is
0.5 mg twice daily for the first
3-7 days. The first dose should be
taken in the evening.
The usual maintenance dose is
1-2 mg twice daily.
• Enlarged prostate
The recommended starting dose is
0.5 mg twice daily for 3-7 days. The
first dose should be taken in the
The usual maintenance dose is 2 mg
twice daily.
• Treatment should be started at the
lowest dose possible.
• Prazosin is not recommended for use
in children under the age of 12 years.
If you take more Prazosin than you
If you (or someone else) swallow a lot
of the tablets all together, or if you think
a child has swallowed any of the
tablets, contact your nearest hospital
casualty department or your doctor
Please take this leaflet, any remaining
tablets, and the container with you to
the hospital or doctor so that they know
which tablets were consumed.

Uncommon side effects (occurring in less than 1 in
100 patients):
• stomach discomfort and/or pain
• chest pain or abnormally fast heart beat
• tingling sensation or numbness
• buzzing or ringing in the ear
• nose bleeds, eye pain or red eyes
• difficulty sleeping
• sweating, itching or itchy skin rash
• painful joints.
Rare side effects (occurring in less than 1 in 1000
• abnormal blood tests that check for liver function
• pain or infection in the pancreas
• abnormally slow heartbeat
• hallucinations (imagining things which are not
really there)
• hair loss
• low blood pressure
• flushing (redness)
• positive ANA (a blood test that checks function of
the immune system)
• abnormal breast tissue development, especially in
• persistent erection of the penis
• an increased tendency to fall asleep if you have a
sleep disorder (narcolepsy)
• leaking of urine (incontinence)
• fever or pain
• inflammation of blood vessels.
If any of the side effects get serious, or if you notice
any side effects not listed in this leaflet, please tell
your doctor or pharmacist.

If you forget to take Prazosin
If you forget to take a tablet, take one as
soon as you remember, unless it is
nearly time to take the next one. DO
Keep out of the reach and sight of children.
NOT take a double dose to make up for a forgotten
Store in a cool, dry place. Protect from light and
If you stop taking Prazosin
Do not use Prazosin after the expiry date that is
DO NOT stop taking your medicine without talking to stated on the outer packaging. The expiry date refers
your doctor first even if you feel better.
to the last day of that month.
Medicines should not be disposed of via wastewater
If you have any further questions on the use of this
or household waste. Ask your pharmacist how to
product, ask your doctor or pharmacist.
dispose of medicines no longer required. These
measures will help to protect the environment.


Like all medicines, Prazosin can cause side effects,
although not everybody gets them.



What Prazosin tablets contain(s):
• The active ingredient is prazosin hydrochloride,
0.5 mg or 1 mg
• The other ingredients are lactose, pre-gelatinised
Stop taking the tablets and tell your doctor
starch, povidone, isopropanol, sodium starch
immediately or go to the casualty department at your
glycolate and magnesium stearate. The 1 mg
nearest hospital if the following happens:
tablets also contain colour dispersed orange (E110).
• an allergic reaction causing swelling of the lips,
What Prazosin tablets look like and contents of the
face or neck leading to severe difficulty in
breathing, skin rash or hives.
• Prazosin 0.5 mg are white tablets coded PRZ 0.5 on
This is a very serious but rare side effect. You may
one side and a twin triangle logo on the reverse
need urgent medical attention or hospitalisation.
• Prazosin 1 mg tablets are orange tablets coded PRZ
The following side effects have been reported at the
1.0 on one side and a twin triangle logo on the
approximate frequencies shown:
Common side effects (occurring in less than 1 in 10
• Prazosin tablets are available in packs of 7, 14, 21,
28, 30, 50, 56, 60, 84, 90, 100, 112, 120, 250, 500 and
• feeling faint, fainting or feeling dizzy, particularly
1000 tablets.
on standing-up
Not all pack sizes may be marketed.
• headache, drowsiness or weakness
Marketing Authorisation Holder and Manufacturer
• unpleasant sensation of forceful beating of the
Marketing Authorisation holder and company
heart (palpitations)
responsible for manufacture: TEVA UK Limited,
• lack of energy, depression or nervousness
Eastbourne, BN22 9AG.
• constipation, diarrhoea, feeling sick (nausea), or
being sick (vomiting)
This leaflet was last revised: February 2011
• dry mouth, nasal stuffiness
PL 00289/1530-1531
• blurred vision
• shortness of breath or rash
• swelling of the feet, ankles or legs
• increase in frequency of passing urine
• inability or difficulty in achieving erection of the
Some patients will feel faint or collapse after the first
dose of Prazosin Tablets (see section 2, Take special
care with Prazosin).


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Source: Medicines and Healthcare Products Regulatory Agency

Disclaimer: Every effort has been made to ensure that the information provided here is accurate, up-to-date and complete, but no guarantee is made to that effect. Drug information contained herein may be time sensitive. This information has been compiled for use by healthcare practitioners and consumers in the United States. The absence of a warning for a given drug or combination thereof in no way should be construed to indicate that the drug or combination is safe, effective or appropriate for any given patient. If you have questions about the substances you are taking, check with your doctor, nurse or pharmacist.