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terazosin

G04CA03

Forms & Strengths

Oral capsules: 1 mg, 2 mg, 5 mg, 10 mg

Adult Dosing

Benign Prostatic Hyperplasia (BPH): Initial 1 mg PO at bedtime; titrate gradually to 2 mg, 5 mg, or 10 mg once daily based on response and tolerability; usual range 10 mg daily.
Hypertension: Initial 1 mg PO at bedtime; titrate to 2 mg, 5 mg, or 20 mg once daily (or divided BID); maximum 20 mg daily.

Pediatric Dosing

Safety and efficacy in pediatric patients have not been established.

Indications

Management of symptomatic benign prostatic hyperplasia (BPH)
Treatment of hypertension (alone or in combination with other antihypertensives)

Mechanism of Action

Selective alpha-1 adrenergic receptor antagonist
Relaxes smooth muscle in the bladder neck and prostate, improving urine flow and BPH symptoms
Relaxes vascular smooth muscle, reducing peripheral vascular resistance and blood pressure

Contraindications

Known hypersensitivity to terazosin or other quinazolines (e.g., doxazosin, prazosin)
History of micturition syncope

Adverse Reactions

Dizziness, lightheadedness, and vertigo
Orthostatic hypotension (especially first-dose phenomenon)
Somnolence, fatigue, and asthenia
Nasal congestion and rhinitis
Peripheral edema
Blurred vision
Priapism (rare)

Drug Interactions

PDE-5 inhibitors (e.g., sildenafil, tadalafil): Increased risk of symptomatic hypotension and syncope
Other antihypertensive agents: Potential additive hypotensive effects
Strong CYP3A4 inhibitors: May potentially alter terazosin metabolism (though less clinically significant compared to other alpha-blockers)

Curated Content: Needs Vetting Before Put to Clinical Use