Class: α1-Adrenergic Blocker
Dosage Forms. Capsule: 0.4 mg
Common FDA Label Indication, Dosing, and Titration.
1. Benign prostatic hyperplasia: 0.4 mg po daily; may titrate to 0.8 mg po daily
1. Neurogenic bladder: 0.4 mg po daily
MOA. Tamsulosin is closely related to quinazoline derivatives that selectively block postsynaptic α1-adrenergic receptors. Total peripheral resistance is reduced through arterial and venous dilatations. Reflex tachycardia that occurs with other vasodilators is infrequent because there is no presynaptic α2-receptor blockade. The drugs also decrease total cholesterol, increase HDL-cholesterol, and may improve glucose tolerance and reduce left ventricular mass during long-term therapy. They increase urine flow in BPH by relaxing smooth muscle tone in the bladder neck and prostate.
Drug Characteristics: Tamsulosin
Medication Safety Issues: Tamsulosin
Drug Interactions: Tamsulosin
Adverse Reactions: Tamsulosin
Efficacy Monitoring Parameters. American Urological Association (AUA) Symptom Score, decrease in residual urine volume, increased urine flow.
Toxicity Monitoring Parameters. Sign/symptoms of hypotension, BP.
Key Patient Counseling Points. Patient should avoid activities requiring coordination until drug effects are realized, as drug may cause vertigo or dizziness. Tell patient to rise slowly from a sitting/lying position, as this drug may cause orthostatic hypotension. Caution patient that syncope or loss of consciousness is possible with first dose or dose increases, especially if patient is in an upright position.
Clinical Pearls. Alpha-blockers commonly used for hypertension. Patients with both hypertension and BPH should avoid taking other alpha-adrenergic blocking agents while taking this drug.