From the Guidelines
Prazosin is recommended as a second-line agent for patients with concomitant benign prostatic hyperplasia (BPH) at a dose of 2-20 mg daily, divided into 2 or 3 doses 1.
Key Points
- Prazosin is an alpha-1 adrenergic receptor blocker used to treat high blood pressure, BPH, and PTSD nightmares.
- For hypertension, the typical starting dose is 1 mg two to three times daily, gradually increasing to 20 mg daily if needed.
- For BPH, doses usually range from 1-5 mg twice daily.
- When used for PTSD nightmares, treatment typically begins with 1 mg at bedtime, potentially increasing to 3-15 mg based on response.
- Prazosin works by relaxing blood vessels and smooth muscle tissue by blocking alpha-1 receptors, reducing resistance to blood flow.
- Common side effects include dizziness, lightheadedness, and first-dose orthostatic hypotension.
- Patients should avoid sudden position changes and be cautious with activities requiring alertness until they know how prazosin affects them.
Considerations
- Prazosin may be considered as a second-line agent in patients with concomitant BPH 1.
- The combination of an alpha-adrenergic receptor blocker and a 5 alpha-reductase inhibitor may be effective in treating symptoms and preventing progression of BPH 1.
- However, the use of prazosin for BPH is not recommended as a first-line treatment, and its effectiveness compared to other alpha blockers is not well established 1.
From the FDA Drug Label
Prazosin hydrochloride capsules are indicated for the treatment of hypertension, to lower blood pressure. Lowering blood pressure reduces the risk of fatal and nonfatal cardiovascular events, primarily strokes and myocardial infarctions Prazosin hydrochloride capsules can be used alone or in combination with other antihypertensive drugs such as diuretics or beta-adrenergic blocking agents.
The primary use of Prazocin is for the treatment of hypertension to lower blood pressure and reduce the risk of cardiovascular events, such as strokes and myocardial infarctions.
- The drug can be used alone or in combination with other antihypertensive medications. 2
From the Research
Prazosin Overview
- Prazosin is a quinazoline derivative that lowers blood pressure by selective alpha-1-receptor antagonism 3
- It has been found to cause less reflex tachycardia than non-selective alpha blockers or direct vasodilators, and is as efficacious as other conventional antihypertensive agents in controlling severe hypertension 3
- Prazosin is also effective in the treatment of benign prostatic hyperplasia (BPH) 4, 5
Clinical Pharmacology
- Prazosin causes a dose-related decrease in blood pressure in humans, with twice-daily dosing sufficient for 24-hour blood pressure control 3
- It has been associated with relatively few side effects, and can be used in combination with other drugs to control blood pressure effectively 3
- Prazosin can cause orthostatic hypotension after the first administration, but this effect disappears after continuous treatment due to plasma volume expansion induced by the drug 6
Therapeutic Role
- Prazosin is an established agent in the therapy of hypertension, and is also effective in the treatment of BPH 4
- It is reasonable to use alpha-Adrenergic Blockers, including prazosin, as the treatment of choice for men with hypertension and BPH 4
- Selective alpha(1)-receptor blockers like prazosin relax prostatic smooth muscle, relieve bladder outlet obstruction, and enhance urine flow with fewer side effects 5