Skip to content
My WebMD Sign In, Sign Up
Drugs & Medications

Minipress

GENERIC NAME(S): PRAZOSIN HCL

Uses

Prazosin is used with or without other medications to treat high blood pressure. Lowering high blood pressure helps prevent strokes, heart attacks, and kidney problems.

Prazosin belongs to a class of medications called alpha blockers. It works by relaxing and widening blood vessels so blood can flow more easily.

OTHER USES: This section contains uses of this drug that are not listed in the approved professional labeling for the drug but that may be prescribed by your health care professional. Use this drug for a condition that is listed in this section only if it has been so prescribed by your health care professional.

This drug may also be used to treat certain blood circulation disorders (Raynaud's phenomenon). Prazosin may also be used to treat problems urinating due to an enlarged prostate (benign prostatic hyperplasia) or to help your body "pass," or get rid of, kidney stones through urination.

How to use Minipress

Take this medication by mouth with or without food, usually two or three times daily or as directed by your doctor. If stomach upset occurs, take with food or milk. The dosage is based on your age, medical condition and response to therapy.

Prazosin can occasionally cause sudden fainting after the first dose and anytime that your dose is increased. To reduce your risk of fainting, the first dose prescribed by your doctor will be the smallest dose available. You should take this first dose as you are going to bed. This will decrease the possibility of fainting. Your dose may be gradually increased. Take your first new dose at bedtime when your dose is increased unless directed otherwise by your doctor.

Use this medication regularly in order to get the most benefit from it. To help you remember, take it at the same time(s) each day. If you are taking this medication for high blood pressure, it is important to continue taking it even if you feel well. Most people with high blood pressure do not feel sick. It may take up to several weeks before the full benefit of this drug takes effect.

Do not stop taking this medication without first consulting your doctor. Some conditions may become worse when the drug is abruptly stopped. Your dose may need to be gradually decreased.

Tell your doctor if your condition worsens (such as your routine blood pressure readings increase).

Side Effects

Headache, drowsiness, tiredness, weakness, blurred vision, nausea, vomiting, diarrhea, or constipation may occur as your body adjusts to the medication. If any of these effects persist or worsen, tell your doctor or pharmacist promptly.

Lightheadedness or dizziness upon standing may also occur, especially after the first dose and shortly after taking a dose of the drug during the first week of treatment. To reduce the risk of dizziness and fainting, get up slowly when rising from a seated or lying position. If dizziness occurs, sit or lie down immediately. Your dose may need to be adjusted.

Remember that your doctor has prescribed this medication because he or she has judged that the benefit to you is greater than the risk of side effects. Many people using this medication do not have serious side effects.

Tell your doctor immediately if any of these unlikely but serious side effects occur: pounding heartbeat, fainting, frequent urination, mental/mood changes (such as depression), swelling of the feet/ankles.

For males, in the very unlikely event you have a painful, prolonged erection (lasting more than 4 hours), stop using this drug and seek immediate medical attention, or permanent problems could occur.

A very serious allergic reaction to this drug is rare. However, seek immediate medical attention if you notice any symptoms of a serious allergic reaction, including: rash, itching/swelling (especially of the face/tongue/throat), severe dizziness, trouble breathing.

This is not a complete list of possible side effects. If you notice other effects not listed above, contact your doctor or pharmacist.

In the US -

Call your doctor for medical advice about side effects. You may report side effects to FDA at 1-800-FDA-1088.

In Canada - Call your doctor for medical advice about side effects. You may report side effects to Health Canada at 1-866-234-2345.

Precautions

Before taking prazosin, tell your doctor or pharmacist if you are allergic to it; or to other alpha blockers (such as doxazosin, terazosin); or if you have any other allergies. This product may contain inactive ingredients, which can cause allergic reactions or other problems. Talk to your pharmacist for more details.

Before using this medication, tell your doctor or pharmacist your medical history, especially of: heart problems (such as low blood pressure), kidney disease, uncontrolled attacks of deep sleep (narcolepsy), prostate cancer.

This drug may make you dizzy or drowsy or cause blurred vision. Do not drive, use machinery, or do any activity that requires alertness or clear vision until you are sure you can perform such activities safely. Do not drive or participate in hazardous activities for 24 hours after your first dose, any increase in your dosage, or restarting treatment. If your doctor prescribes any additional blood pressure drugs, avoid driving and hazardous activities for 24 hours after your first dose of the new medication. Limit alcoholic beverages.

To reduce the risk of dizziness and fainting, be careful when standing for long periods. Avoid getting overheated during exercise and hot weather. When first starting this drug, avoid situations where you may be injured if you faint.

Before having surgery (including cataract eye surgery), tell your doctor or dentist that you are taking this medication and about all the products you use (including other prescription drugs, nonprescription drugs, and herbal products).

Older adults may be more sensitive to the side effects of this drug, especially dizziness and fainting. These side effects can increase the risk of falling.

During pregnancy, this medication should be used only when clearly needed. Discuss the risks and benefits with your doctor.

Prazosin passes into breast milk. Consult your doctor before breast-feeding.

Interactions

The effects of some drugs can change if you take other drugs or herbal products at the same time. This can increase your risk for serious side effects or may cause your medications not to work correctly. These drug interactions are possible, but do not always occur. Your doctor or pharmacist can often prevent or manage interactions by changing how you use your medications or by close monitoring.

To help your doctor or pharmacist give you the best care, be sure to tell your doctor or pharmacist about all the products you use (including prescription drugs, nonprescription drugs, and herbal products) before starting treatment with this product. While using this product, do not start, stop, or change the dosage of any other medicines you are using without your doctor's approval.

Some of the products that may interact with this drug include: beta blockers (such as atenolol, metoprolol, propranolol), verapamil, drugs to treat erectile dysfunction-ED or pulmonary hypertension (such as sildenafil, tadalafil).

Tell your doctor or pharmacist if you also take drugs that cause drowsiness, lower blood pressure, or make it difficult for you to urinate, such as: certain antihistamines (such as diphenhydramine), anti-seizure drugs (such as carbamazepine), medicine for sleep or anxiety (such as alprazolam, diazepam, zolpidem), muscle relaxants, narcotic pain relievers (such as codeine), psychiatric medicines (such as chlorpromazine, risperidone, amitriptyline, trazodone).

Check the labels on all your medicines (such as cough-and-cold products, diet aids, nonsteroidal anti-inflammatory drugs-NSAIDs for pain/fever reduction) because they may contain ingredients (such as pseudoephedrine, phenylephrine, chlorpheniramine, diphenhydramine, clemastine, ibuprofen, naproxen) that could increase your blood pressure or cause a fast heartbeat. Ask your pharmacist about the safe use of those products.

This medication may interfere with certain laboratory tests (including pheochromocytoma screening test), possibly causing false test results. Make sure laboratory personnel and all your doctors know you use this drug.

This document does not contain all possible interactions. Keep a list of all the products you use. Share this list with your doctor and pharmacist to lessen your risk for serious medication problems.

Overdose

If overdose is suspected, contact a poison control center or emergency room immediately. US residents can call their local poison control center at 1-800-222-1222. Canada residents can call a provincial poison control center. Symptoms of overdose may include: severe drowsiness, slow reactions.

Notes

Do not share this medication with others.

Lifestyle changes such as stress reduction programs, exercise, and dietary changes may increase the effectiveness of this medicine. Talk to your doctor or pharmacist about lifestyle changes that might benefit you.

Have your blood pressure and heart rate checked regularly while taking this medication. Learn how to monitor your own blood pressure, and share the results with your doctor.

Missed Dose

If you miss a dose, take it as soon as you remember. If it is near the time of the next dose, skip the missed dose and resume your usual dosing schedule. Do not double the dose to catch up.

Storage

Store at room temperature away from light and moisture. Refer to storage information printed on the bottle for the exact temperature range. If you have any questions about storage, ask your pharmacist. Do not store in the bathroom. Keep all medicines away from children and pets.

Do not flush medications down the toilet or pour them into a drain unless instructed to do so. Properly discard this product when it is expired or no longer needed. Consult your pharmacist or local waste disposal company for more details about how to safely discard your product.

Information last revised March 2013. Copyright(c) 2013 First Databank, Inc.

Images

MINIPRESS 1 MG CAPSULE
MINIPRESS 1 MG CAPSULE
View Larger Picture
color
white
shape
oblong
imprint
MINIPRESS, PFIZER 431
MINIPRESS 2 MG CAPSULE
MINIPRESS 2 MG CAPSULE
View Larger Picture
color
white
shape
oblong
imprint
MINIPRESS, PFIZER 437
MINIPRESS 5 MG CAPSULE
MINIPRESS 5 MG CAPSULE
View Larger Picture
color
white
shape
oblong
imprint
MINIPRESS, PFIZER 438
MINIPRESS 1 MG CAPSULE
MINIPRESS 1 MG CAPSULE

Identification

color
white
shape
oblong
imprint
MINIPRESS, PFIZER 431
This medicine is a white, oblong capsule imprinted with "MINIPRESS" and "PFIZER 431".
MINIPRESS 2 MG CAPSULE
MINIPRESS 2 MG CAPSULE

Identification

color
white
shape
oblong
imprint
MINIPRESS, PFIZER 437
This medicine is a white, oblong capsule imprinted with "MINIPRESS" and "PFIZER 437".
MINIPRESS 5 MG CAPSULE
MINIPRESS 5 MG CAPSULE

Identification

color
white
shape
oblong
imprint
MINIPRESS, PFIZER 438
This medicine is a white, oblong capsule imprinted with "MINIPRESS" and "PFIZER 438".

Add to Cabinet

Add Adderall to my medicine cabinet.

Did you know?

With WebMD's Medicine Cabinet, you can check interactions with drugs.

Go to medicine cabinet

Selected from data included with permission and copyrighted by First Databank, Inc. This copyrighted material has been downloaded from a licensed data provider and is not for distribution, expect as may be authorized by the applicable terms of use.

CONDITIONS OF USE: The information in this database is intended to supplement, not substitute for, the expertise and judgment of healthcare professionals. The information is not intended to cover all possible uses, directions, precautions, drug interactions or adverse effects, nor should it be construed to indicate that use of a particular drug is safe, appropriate or effective for you or anyone else. A healthcare professional should be consulted before taking any drug, changing any diet or commencing or discontinuing any course of treatment.

More about Drugs and Medications

Newsletters

Subscribe to free WebMD newsletters.

  • WebMD Daily

    WebMD Daily

    Subscribe to the WebMD Daily, and you'll get today's top health news and trending topics, and the latest and best information from WebMD.

  • Men's Health

    Men's Health

    Subscribe to the Men's Health newsletter for the latest on disease prevention, fitness, sex, nutrition, and more from WebMD.

  • Women's Health

    Women's Health

    Subscribe to the Women's Health newsletter for the latest on disease prevention, fitness, sex, diet, anti-aging, and more from WebMD.

By clicking Submit, I agree to the WebMD Terms & Conditions & Privacy Policy

URAC: Accredited Health Web Site HONcode Seal AdChoices