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Prazosin

    Brands

    DEA Class;  Rx

    Common Brand Names; Minipress, Prazin, Prazo

    • Alpha Blockers, Antihypertensives

    Oral alpha-blocker; used primarily for HTN; similar to doxazosin and terazosin, but is shorter-acting; has also been used for CHF, but is seldom used for this indication due to the development of tolerance for drug efficacy.

    Indicated for the treatment of hypertension.

    For the treatment of hypertensive urgency, especially crises associated with increased circulating catecholamines.
    For the prevention of Raynaud’s phenomenon.
    For the treatment of symptomatic benign prostatic hyperplasia (BPH).
    For the treatment of nightmares related to posttraumatic stress disorder (PTSD).
     

    Hypersensitivity

    • Dizziness (10%)
    • Drowsiness (8%)
    • Headache (8%)
    • Weakness (7%)
    • Asthenia (6.5%)
    • Nausea (5%)
    • Palpitation (5%)
    • Edema
    • Orthostatic hypotension
    • Syncope
    • Fever
    • Rash
    • Abdominal discomfort/pain
    • Diarrhea
    • Vomiting
    • Abnormal liver function tests
    • Impotence
    • Pancreatitis
    • Urinary incontinence

    Risk of syncope; has no relation to plasma prazosin concentration; if syncope occurs, place patient in the recumbent position and treat supportively as necessary

    Discontinue if angina symptoms occur or worsen

    May cause CNS depression, which may impair physical or internal abilities; use caution when performing tasks that require mental alertness

    May impair ability to drive/perform hazardous tasks due to dizziness

    History of narcolepsy – May exacerbate

    Cataract surgery – Linked to intraoperative floppy iris syndrome

    Concomitant administration with PDE-5 inhibitor (eg, sildenafil) can result in additive blood pressure-lowering effects and symptomatic hypotension; initiate PDE-5 inhibitor therapy at lowest dose

    First dose effect may occur, causing a sudden and drastic fall in blood pressure after administration of the first dose.

    May exacerbate heart failure

    Pregnancy category: C

    Lactation: Excreted in breast milk; use caution

    Adults

    20 mg/day PO for heart failure or hypertension (some patients have required up to 40 mg/day PO for hypertension); 9 mg/day PO for benign prostatic hyperplasia (BPH).

    Elderly

    20 mg/day PO for heart failure or hypertension (some patients have required up to 40 mg/day PO for hypertension); 9 mg/day PO for benign prostatic hyperplasia (BPH).

    Adolescents

    No maximum dosage information is available. See adult and children’s dosage.

    Children

    15 mg/day PO or 400 mcg/kg/day PO.

    Prazosin hydrochloride

    capsule

    • 1mg
    • 2mg
    • 5mg