Generic Name

Tamsulosin

Mechanism

• Selective α1A‑receptor blockade:
• Predominantly blocks α1A‑adrenergic receptors in the prostate and bladder neck.
• Reduces smooth‑muscle tone and spasm, leading to improved urinary flow rates.
• Minimal α1B/α1D activity:
• Limits systemic vasodilatory effects, decreasing the risk of orthostatic hypotension compared to non‑selective α‑blockers.

Pharmacokinetics

• Absorption: Oral dosing; peak plasma concentration (Cmax) at ~2 h post‑dose (Tmax).
• Bioavailability: ~25 % (first‑pass hepatic metabolism).
• Protein binding: ~85 % to plasma proteins.
• Metabolism: Predominantly via CYP3A4, with minor CYP2D6 contribution.
• Elimination: Primarily via feces (≈45 %) and urine (≈30 %).
• Half‑life: 9–15 h (steady‑state trough concentration reached by day 2).

Indications

• Benign prostatic hyperplasia (BPH):
• Relief of lower‑tract symptoms such as urinary hesitancy, weak stream, and incomplete emptying.
• Symptomatic prostate enlargement in men ≥ 40 yrs with moderate to severe LUTS.

Contraindications

• Allergy to tamsulosin or any α‑blocker component.
• Severe hepatic impairment (Child‑Pugh C).
• Concurrent use with potent CYP3A4 inhibitors (e.g., ketoconazole, erythromycin) can ↑ plasma concentration → increased hypotension risk.
• Caution with antihypertensives or diuretics that may amplify orthostatic hypotension.

Dosing

• Standard adult dose:
• 0.4 mg orally once nightly (start at bedtime).
• May titrate to 0.8 mg nightly after ≥ 2 weeks if symptoms persist.
• Special populations:
• Elderly: same dose; monitor blood pressure closely.
• Hepatic dysfunction: 0.4 mg nightly; avoid titration.
• Administration tips:
• Take with or without food; consistent timing improves tolerability.

Adverse Effects

• Common (≥ 1 %):
• Orthostatic hypotension: dizziness, light‑headedness, syncope (first‑dose phenomenon).
• Flushing, nasal congestion, headache.
• Retrograde ejaculation (≈ 10 % of men).
• Serious (rare):
• Severe hypotension, cardiac arrhythmias.
• Anaphylaxis (hypersensitivity reaction).

Monitoring

• Vital signs: BP and heart rate at baseline, 30 min post‑dose (first dose), and periodically thereafter.
• Liver function tests if dose adjustment or long‑term therapy is considered.
• Urinary flow: Post‑treatment uroflowmetry or symptom score (IPSS) to evaluate efficacy.

Clinical Pearls

• First‑dose phenomenon: Initiate therapy at bedtime; instruct patients to remain seated or lie down for 30–60 min after the first dose to minimize syncope risk.
• Combination therapy: Tamsulosin + 5‑α‑reductase inhibitor can yield additive benefits for LUTS; consider adding finasteride for prostate volume > 30 mL or rising PSA.
• Retrograde ejaculation: Counsel patients with fertility concerns; the effect is usually reversible upon discontinuation.
• Drug interactions: Avoid concurrent use of tamsulosin with antihypertensive agents that lower BP (e.g., clonidine) or strenuous activities that require rapid BP changes.
• Pregnancy & Lactation: Contraindicated; advise abstinence or use of effective contraception during treatment.

--
• *This drug card is intended for educational purposes. Always refer to official prescribing information and clinical guidelines before initiating therapy.*