- High Blood Pressure Slideshow Pictures
- Take the Salt Quiz!
- Lowering Blood Pressure Exercise Tips Pictures
- What is prazosin-oral, and how does it work (mechanism of action)?
- What brand names are available for prazosin-oral?
- Is prazosin-oral available as a generic drug?
- Do I need a prescription for prazosin-oral?
- What are the side effects of prazosin-oral?
- What is the dosage for prazosin-oral?
- Which drugs or supplements interact with prazosin-oral?
- Is prazosin-oral safe to take if I'm pregnant or breastfeeding?
- What else should I know about prazosin-oral?
What is prazosin-oral, and how does it work (mechanism of action)?
Prazosin (Minipress) is an oral medicine used to treat high blood pressure. Prazosin is a competitive alpha-1 adrenergic receptor blocker. By blocking alpha-1 receptors on muscle cesll that surround blood vessels, prazosin causes vasodilation (widening) of the blood vessels, and consequently decreases the resistance of blood flow. The overall benefit of its use is a decrease in blood pressure.
Prazosin seems to have a bigger impact on reducing the diastolic blood pressure than systolic blood pressure. Diastolic blood pressure is indicated by the second set of numbers in the blood pressure reading and corresponds to the minimum pressure in the arteries when the heart muscles are relaxed and the chambers of the heart are filling with blood.
Prazosin was approved by the FDA in 1976.
What are the side effects of prazosin-oral?
The most common side effects associated with prazosin treatment include:
Patients can lower their chance of feeling dizzy or passing out by:
- rising slowing from a sitting or lying position,
- climbing stairs slowly,
- avoiding alcohol, and
- drinking lots of water especially in hot weather or while being active.
Additionally, patients should have their blood pressure checked regularly.
Less common side effects include:
- water retention (edema),
- orthostatic hypotension,
- shortness of breath,
- fainting (syncope),
- motion sickness,
- urinary frequency,
- blurred vision,
- reddened sclera,
- dry mouth, and nasal
Rare side effects include:
- stomach pain,
- liver problems,
- tachycardia (fast heartbeat),
- paresthesia (numbness, tingling, burning, prickling),
- hair loss,
- urinary incontinence (loss of bladder control),
- sexual dysfunction,
- prolonged erection,
- ringing in the ears,
- fever, and
- joint pain.
Other side effects reported in post-marketing trials include:
What is the dosage for prazosin-oral?
- The dose of prazosin should be adjusted based on the individual patient response.
- For the treatment of high blood pressure: Most patients are started with 1 mg by mouth 2-3 times a day. To decrease the risk of orthostatic hypotension the first dose may be given at bedtime. Orthostatic hypotension is a drop in blood pressure when standing up from a sitting or lying position. Dosage may be increased gradually over time to a total daily dose of 20 mg given in multiple doses.
- If adding another blood pressure lowering agent or water pill (diuretic) to prazosin therapy, the dose of prazosin should be reduced to 1-2 mg by mouth three times a day, followed by slow increases in dose as needed.
- As elderly patients are more sensitive to the side effects of low blood pressure, dose reduction in the elderly is necessary. Most elderly patients are started on 1 mg by mouth 1-2 times daily.
- The safety and effectiveness of prazosin in children has not been established.
Which drugs or supplements interact with prazosin-oral?
Use of prazosin with other blood pressure lowering medicines or water pills may cause an additive blood pressure lowering effect.
Use of phosphodiesterase-5 (PDE-5) inhibitors, for example, sildenafil (Viagra), tadalafil (Cialis), vardenafil (Levitra) with prazosin can also cause an additive decrease in blood pressure. To decrease the risk of precipitating side effects associated with low blood pressure, the lowest possible dose of PDE-5 inhibitors should be used in patients taking prazosin.
Is prazosin-oral safe to take if I'm pregnant or breastfeeding?
There are no adequate and well controlled studies of prazosin use in pregnancy. Prazosin should be used during pregnancy only if the potential benefit justifies the potential risk to the mother and the unborn baby. Prazosin is classified as FDA pregnancy risk category C (adverse effects in animals but inadequate data in humans).
Small amounts of prazosin were found in human milk after oral administration. Due to the lack of conclusive safety data, prazosin should be used cautiously in nursing mothers.
What else should I know about prazosin-oral?
What preparations of prazosin-oral are available?
Oral capsules: 1, 2, and 5 mg.
How should I keep prazosin-oral stored?
Capsules should be stored at room temperature, between 59 F and 86 F (15 C and 30 C).
Quick GuideHow to Lower Blood Pressure: Exercise Tips
Prazosin hydrochloride (Minipress) is a drug prescribed to treat high blood pressure (hypertension), BPH (benign prostatic hyperplasia, hypertensive urgency, PTSD, and Raynaud's phenomenon. Side effects, drug interactions, warning and precautions, dosing, storage, breastfeeding, and pregnancy safety information should be reviewed prior to taking this drug.
Multimedia: Slideshows, Images & Quizzes
High Blood Pressure (Hypertension) Quiz: Symptoms, Signs & Causes
Take this quiz and test your IQ of high blood pressure (hypertension), the cardiovascular disease that causes most strokes and...
PTSD Quiz: Test your IQ of Posttraumatic Stress Disorder
Can you have PTSD even if you've never been to war? Take the Posttraumatic Stress Disorder Quiz to learn about PTSD, who gets it,...
Benign Prostatic Hyperplasia (Enlarged Prostate) Quiz
Take the Enlarge Prostate Quiz and challenge your knowledge of prostate problems. Learn causes, symptoms, treatments, and...
High Blood Pressure (Hypertension): Symptoms, Causes, Treatments
What causes high blood pressure (hypertension)? Know the warning signs and symptoms of high blood pressure. Read about high blood...
Related Disease Conditions
Raynaud's phenomenon is characterized by a pale-blue-red sequence of color changes of the digits, most commonly after exposure to...
High Blood Pressure (Hypertension) Signs, Causes, Diet, and Treatment
High blood pressure (hypertension) is a disease in which pressure within the arteries of the body is elevated. About 75 million...
Enlarged Prostate (BPH, Benign Prostatic Hyperplasia)
Benign prostatic hyperplasia (BPH or enlarged prostate) is very common in men over 50 years of age. Half of all men over the...
High Blood Pressure Treatment (Natural Home Remedies, Diet, Medications)
High blood pressure (hypertension) means high pressure (tension) in the arteries. Treatment for high blood pressure include...
Posttraumatic Stress Disorder
Post-traumatic stress disorder (PTSD), a psychiatric condition, can develop after any catastrophic life event. Symptoms include...
Febrile seizures, or convulsions caused by fever, can be frightening in small children or infants. However, in general, febrile...
Treatment & Diagnosis
Medications & Supplements
Prevention & Wellness
Health Solutions From Our Sponsors
Report Problems to the Food and Drug Administration
You are encouraged to report negative side effects of prescription drugs to the FDA. Visit the FDA MedWatch website or call 1-800-FDA-1088.