Doxazosin Tablets

Mechanism

Doxazosin selectively blocks postsynaptic alpha-1 adrenergic receptors. This causes vasodilation, reduced peripheral vascular resistance, and improved urinary outflow in BPH by relaxing smooth muscle in the bladder neck and prostate.

Pharmacokinetics

• Absorption: Well absorbed orally; bioavailability ~65%.
• Distribution: Highly protein bound (~98%).
• Metabolism: Extensively metabolized in liver.
• Elimination: Excreted in feces and urine.
• Half-life: ~22 hours (allows once-daily dosing).

Side Effects

• Dizziness, lightheadedness
• Orthostatic hypotension
• Fatigue
• Headache
• Edema
• Rare: syncope, palpitations

Contraindication

• Hypersensitivity to Doxazosin or other quinazolines
• History of orthostatic hypotension
• Severe hepatic impairment

Interaction

• Other antihypertensives: Additive hypotensive effect.
• PDE-5 inhibitors (sildenafil, tadalafil): Increased risk of hypotension.
• NSAIDs: May reduce antihypertensive efficacy.

Warning and Precautions

• First-dose effect: start with low dose to avoid syncope.
• Monitor blood pressure regularly.
• Use cautiously in patients with hepatic impairment.
• Advise patients to rise slowly from sitting/lying positions.
• Pregnancy/Lactation: Use only if clearly needed under medical supervision.

Dosage

As directed by the Physician.