Lopress Mechanism of Action

Pharmacology: Pharmacodynamics: Prazosin hydrochloride is a quinazolin-derivative postsynaptic α₁ adrenergic blocking agent.
Prazosin hydrochloride causes a reduction in total peripheral resistance by dilation of vascular smooth muscle, which may be related to postsynaptic α₁ adrenergic receptors blockade.
Pharmacokinetics: Prazosin is readily absorbed from the gastrointestinal tract following oral administration and peak plasma concentration occur 1 to 3 hours after an oral dose. The oral bioavailability is variable and a range of 43% to 85% has been reported. Prazosin is highly bound to plasma proteins (92% to 97%). It is extensively metabolized in the liver and some of the metabolites are reported to have hypotensive activity. It is excreted as the metabolites and 5% to 11% as unchanged Prazosin mainly in the feces via the bile, less than 10% is excreted in the urine. It is not dialyzable. The plasma half-life of Prazosin after oral administration has been reported to be 2-4 hours.