Kornam (Terazosin Hydrochloride Dihydrate)

Terazosin is indicated for conditions that involve excessive alpha‑1 adrenergic activity, primarily affecting vascular tone and prostate smooth muscle.

• Hypertension: reduces systemic vascular resistance, helping to achieve target blood pressure levels.
• Benign prostatic hyperplasia (BPH): relaxes prostate and bladder neck smooth muscle, improving urinary flow and reducing urgency.

• Terazosin acts as a competitive antagonist at alpha‑1 adrenergic receptors located on vascular smooth muscle and on the smooth muscle of the prostate and bladder neck. By blocking these receptors, it prevents norepinephrine‑mediated contraction, leading to vasodilation and decreased peripheral resistance, as well as relaxation of prostatic tissue, which lowers blood pressure and eases urinary obstruction.

Terazosin may be associated with a range of adverse reactions, which are categorized by frequency and severity.

Common Side Effects

• Dizziness: feeling of light‑headedness, especially when standing quickly.
• Headache: mild to moderate pain in the head.
• Fatigue: general tiredness or lack of energy.
• Nasal congestion: blocked or runny nose.

Serious or Rare Side Effects

• Severe hypotension or syncope: marked drop in blood pressure that can cause fainting.
• Priapism: prolonged, painful erection requiring urgent medical attention.
• Anaphylactic reaction: rare severe allergic response with rash, swelling, and breathing difficulty.

When prescribing or dispensing Terazosin, several precautionary measures should be observed to ensure patient safety.

• Blood pressure monitoring: check baseline and periodic readings to avoid excessive hypotension.
• Renal and hepatic function: assess before initiation and adjust if impairment is present.
• Concomitant antihypertensives: review other blood‑pressure‑lowering drugs to prevent additive effects.
• Orthostatic hypotension risk: advise patients to rise slowly from sitting or lying positions.
• Discontinuation: avoid abrupt stopping; taper dose under medical supervision.
• Store at room temperature: keep in the original container, protect from moisture and direct sunlight.

Terazosin can interact with other medicines, altering its efficacy or safety profile.

Major Interactions (Avoid)

• Other alpha‑1 blockers (e.g., prazosin, doxazosin): combined use may cause profound hypotension.
• Potent CYP3A4 inhibitors (e.g., ketoconazole, itraconazole): increase terazosin plasma levels, raising risk of adverse effects.
• Strong antihypertensive agents (e.g., clonidine, nitroprusside): additive blood‑pressure‑lowering effect.

Moderate Interactions (Monitor Closely)

• Diuretics: may enhance orthostatic hypotension; monitor fluid status and blood pressure.
• Phosphodiesterase‑5 inhibitors (e.g., sildenafil): can cause symptomatic hypotension; adjust dose if needed.