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- 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:
Quick GuideHow to Lower Blood Pressure: Exercise Tips
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).
REFERENCE: FDA Prescribing Information.
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.
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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 age of 50 develop symptoms of BPH, but few need medical treatment. This noncancerous enlargement of the prostate can impede urine flow, slow the flow of urine, create the urge to urinate frequently and cause other symptoms like complete blockage of urine and urinary tract infections. More serious symptoms are urinary tract infections (UTIs) and complete blockage of the urethra, which may be a medical emergency.
BPH is not cancer. Not all men with the condition need treatment, and usually is closely monitored if no symptoms are present. Treatment measures usually are reserved for men with significant symptoms, and can include medications, surgery, microwave therapy, and laser procedures. Men can prevent prostate problems by having regular medical checkups that include a prostate exam. Contact your doctor or other medical professional if you have these symptoms:
- Painful urination
- Blood in the urine
- Difficult urinating
- A frequent urge to urinate
- Dribbling of urine
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Febrile SeizuresFebrile seizures, or convulsions caused by fever, can be frightening in small children or infants. However, in general, febrile seizures are harmless. Febrile seizure is not epilepsy. It is estimated that one in every 25 children will have at least one febrile seizure. It is important to know what to do to help your child if he/she has a febrile seizure. Some of the features of a febrile seizure include:
- losing consciousness,
- moving limbs on both sides of the body,
- lasts 1-2 minutes.
High Blood Pressure HypertensionHigh blood pressure is defined as a pressure of 140/90 mmHg or higher in the arteries. Genetic factors, high salt intake, and increased arterial stiffness cause high blood pressure. Dizziness, headache, nausea, and shortness of breath are just a few symptoms of high blood pressure. Untreated high blood pressure increases the risk of heart disease, kidney disease, atherosclerosis, eye damage, stroke, and increased risk of aneurysms. High blood pressure can be managed with weight loss, lifestyle changes, and medication.
High Blood Pressure Medication
High blood pressure (hypertension) medications include drugs from a variety of different drug classes and types.
- ACE inhibitors
- ARB (angiotensin receptor blockers)
- Beta blockers
- Calcium channel blockers (CCBs)
- Alpha-beta blockers
Clonidine (Catapres) and minoxidil also are drugs prescribed for the treatment of high blood pressure. Side effects, warnings and precautions, safety information, and pregnancy and breastfeeding safety information should be reviewed prior to taking any medication.
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ParathyroidectomyParathyroidectomy is the removal of one or more of the parathyroid glands to treat hyperparathyroidism. Risks of parathyroidectomy include:
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- prolonged pain,
- impaired healing,
- and recurrence of the tumor.
Posttraumatic Stress DisorderPost-traumatic stress disorder (PTSD), a psychiatric condition, can develop after any catastrophic life event. Symptoms include nightmares, flashbacks, sweating, rapid heart rate, detachment, amnesia, sleep problems, irritability, and exaggerated startle response. Treatment may involve psychotherapy, group support, and medication.
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Raynaud's PhenomenonRaynaud's phenomenon is characterized by a pale-blue-red sequence of color changes of the digits, most commonly after exposure to cold. Occurring as a result of spasm of blood vessels, the cause is unknown. Symptoms of Raynaud's phenomenon depend on the severity, frequency, and duration of the blood vessel spasm. Treatments include protection of the digits, medications, and avoiding emotional stresses, smoking, cold temperature, and tools that vibrate the hands.