Maxflow Mechanism of Action

Pharmacology: Mechanism of Action: Tamsulosin HCl binds selectively and competitively with prostatic α_1A-adrenoceptors. It brings about relaxation of prostatic and urethral smooth muscle resulting in an increase in urinary flow rate and a reduction in symptoms of benign prostatic hyperplasia (BPH). It also improves the irritative symptoms in which bladder instability plays an important role.
Pharmacokinetics: Absorption: Absorption of Tamsulosin HCl is essentially complete (>90%) following oral administration under fasting conditions. The time to maximum concentration (T_max) is reached by four to five hours under fasting conditions and by six to seven hours when Tamsulosin HCl capsules are administered with food. Taking Tamsulosin HCl capsules under fasted conditions results in a 30% increase in bioavailability (AUC) and 40% to 70% increase in peak concentrations (C_max) compared to fed conditions.
Distribution: Tamsulosin HCl is extensively bound to human plasma proteins (94% to 99%), primarily alpha-1 acid glycoprotein (AAG), with linear binding over a wide concentration range. There is a minimal distribution to the brain, spinal cord and testes.
Metabolism: Tamsulosin HCl has a low first pass effect, being metabolized slowly. Tamsulosin HCl is extensively metabolized by cytochrome P450 enzymes in the liver. Most HCl is present in the plasma in the form of unchanged medicine.
Excretion: Tamsulosin HCl and its metabolites are mainly excreted in the urine with less than 10% of a dose being present in the form of unchanged medicine. After a single dose of Tamsulosin HCl in the fed state and in the steady state in patients, elimination half-lives of about 10 and 13 hours respectively have been measured.
Special Populations: Geriatrics: Intrinsic clearance is independent of Tamsulosin HCl binding to AAG, but diminishes with age, resulting in a 40% overall higher exposure (AUC) in subjects of age 55 to 75 years compared to subjects of age 20 to 32 years.
Renal Impairment: Patients with renal impairment [mild-moderate (30 ≤ Cl_cr < 70 mL/min/1.73 m²)] do not require dose adjustment or moderate-severe (10 ≤ Cl_cr < 30 mL/min/1.73 m²)] do not require dose adjustment.