Pharmacology of Prazosin (Minipress); Pharmacokinetics, Mechanism of Action, Uses, Effects скачать в хорошем качестве

Pharmacology of Prazosin (Minipress); Pharmacokinetics, Mechanism of Action, Uses, Effects

Prazosin (brand name: Minipress) is an alpha-1 adrenergic receptor antagonist primarily used in the management of hypertension, as well as other conditions like benign prostatic hyperplasia (BPH) and post-traumatic stress disorder (PTSD). Here's a detailed breakdown of its pharmacology: Mechanism of Action Selective Alpha-1 Adrenergic Antagonist: Prazosin blocks alpha-1 adrenergic receptors in vascular smooth muscle, leading to: Relaxation of arterial and venous smooth muscle. Reduction in total peripheral vascular resistance and venous return to the heart. The result is a decrease in blood pressure (antihypertensive effect). In the bladder neck and prostate: Relaxes smooth muscle, improving urinary flow in cases of BPH. In PTSD (off-label use): Thought to reduce sympathetic outflow, which may mitigate nightmares and sleep disturbances. Pharmacokinetics Administration: Given orally, often in divided doses. Absorption: Well-absorbed after oral administration, with peak plasma concentrations occurring in 1–3 hours. Metabolism: Extensively metabolized in the liver. Excretion: Metabolites and a small amount of the unchanged drug are excreted via urine and feces. Half-Life: The plasma elimination half-life is approximately 2–3 hours, requiring multiple doses per day in some cases. Indications Hypertension: Used as a second-line or adjunct treatment in resistant hypertension. Benign Prostatic Hyperplasia (BPH) (Off-label): Alleviates urinary symptoms by relaxing the bladder neck and prostate smooth muscle. Post-Traumatic Stress Disorder (PTSD) (Off-label): Reduces nightmares and hyperarousal symptoms associated with PTSD. Raynaud’s Phenomenon (Off-label): Improves blood flow by relaxing peripheral vascular smooth muscle. Adverse Effects Common Side Effects: First-Dose Hypotension: A marked drop in blood pressure, especially with the initial dose or dose increases. Dizziness and lightheadedness. Fatigue. Headache. Serious Adverse Effects: Syncope (fainting), often associated with the "first-dose effect." Rarely, tachycardia as a reflex response to vasodilation. #Prazosin