Pharmacology of Silodosin (Rapaflo) ; Pharmacokinetics, Mechanism of Action, Uses, Effects скачать в хорошем качестве

Pharmacology of Silodosin (Rapaflo) ; Pharmacokinetics, Mechanism of Action, Uses, Effects

Silodosin (brand name: Rapaflo) is a selective alpha-1 adrenergic receptor antagonist primarily used in the management of benign prostatic hyperplasia (BPH) to improve urinary flow. Here’s a detailed overview of its pharmacology: Mechanism of Action Selective Alpha-1A Adrenergic Receptor Blockade: Silodosin selectively targets alpha-1A adrenergic receptors, which are highly concentrated in the smooth muscle of the prostate, bladder neck, and urethra. Blocking these receptors leads to relaxation of the smooth muscle, reducing resistance to urinary flow and relieving symptoms of BPH such as urinary hesitancy, weak stream, and incomplete bladder emptying. Its high selectivity for alpha-1A receptors minimizes systemic effects on alpha-1B receptors found in vascular smooth muscle, reducing the risk of hypotension compared to less selective alpha blockers. Pharmacokinetics Administration: Taken orally, usually as a once-daily dose with food to optimize absorption and reduce gastrointestinal side effects. Absorption: Rapidly absorbed, with peak plasma concentrations occurring within 2–3 hours after administration. Metabolism: Extensively metabolized in the liver by UGT2B7 and partially by CYP3A4, forming an active metabolite (KMD-3213G), which contributes to its therapeutic effects. Excretion: Primarily excreted via feces (54%) and urine (34%), with both the parent compound and metabolites being eliminated. Half-Life: The terminal elimination half-life is approximately 13 hours, allowing once-daily dosing. Indications Benign Prostatic Hyperplasia (BPH): Used to alleviate lower urinary tract symptoms (LUTS) associated with BPH, such as frequent urination, nocturia, and weak urinary stream. Adverse Effects Common Side Effects: Retrograde ejaculation (a hallmark adverse effect associated with silodosin). Dizziness, particularly when standing up (postural hypotension). Nasal congestion and runny nose. Diarrhea and other mild gastrointestinal symptoms. Serious Adverse Effects: Rare cases of severe hypotension or syncope, although less common due to its receptor selectivity. Intraoperative Floppy Iris Syndrome (IFIS): This syndrome has been reported in patients undergoing cataract surgery who were treated with alpha blockers, including silodosin. #Silodosin