Prazosin (By mouth)
Treats high blood pressure.
When This Medicine Should Not Be Used
How to Use This Medicine
- Take your medicine as directed. Your dose may need to be changed several times to find what works best for you.
- Missed dose: Take a dose as soon as you remember. If it is almost time for your next dose, wait until then and take a regular dose. Do not take extra medicine to make up for a missed dose.
- Store the medicine in a closed container at room temperature, away from heat, moisture, and direct light.
Drugs and Foods to Avoid
Ask your doctor or pharmacist before using any other medicine, including over-the-counter medicines, vitamins, and herbal products.
- Some foods and medicines can affect how prazosin works. Tell your doctor if you also use any of the following:
- Diuretic (water pill)
- Other blood pressure medicine
- Sildenafil, tadalafil, vardenafil, or similar medicines
Warnings While Using This Medicine
- Tell your doctor if you are pregnant or breastfeeding, or if you have kidney disease.
- Tell your eye doctor that you are taking this medicine, if you also have cataracts.
- This medicine may make you dizzy or drowsy. Do not drive or do anything else that could be dangerous until you know how this medicine affects you.
- This medicine could lower your blood pressure too much, especially when you first use it or if you are dehydrated. Stand or sit up slowly if you feel lightheaded or dizzy. Alcohol may make this problem worse.
- Tell any doctor or dentist who treats you that you are using this medicine. This medicine may affect certain medical test results.
- Your doctor will check your progress and the effects of this medicine at regular visits. Keep all appointments.
- Keep all medicine out of the reach of children. Never share your medicine with anyone.
Possible Side Effects While Using This Medicine
Call your doctor right away if you notice any of these side effects:
- Allergic reaction: Itching or hives, swelling in your face or hands, swelling or tingling in your mouth or throat, chest tightness, trouble breathing
- Fast, pounding, or uneven heartbeat
- Lightheadedness, dizziness, or fainting
If you notice these less serious side effects, talk with your doctor:
- Mild dizziness, tiredness, or weakness
If you notice other side effects that you think are caused by this medicine, tell your doctor
Call your doctor for medical advice about side effects. You may report side effects to FDA at 1-800-FDA-1088
- Last reviewed on 7/4/2015
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