ATC Φάρμακα Δραστικές ICPC2 ICD10 Ιατρική στην Πράξη Νοσήματα Λοιμώξεις Εμβόλια Πρωτόκολλα
  • Terazosin
  • indication:For the treatment of symptomatic BPH and mild to moderate hypertension.
  • pharmacologypharmacology:
  • mechanism: In general, α<sub>1</sub>-adrenergic receptors mediate contraction and hypertrophic growth of smooth muscle cells. α<sub>1</sub>-Receptors are 7-transmembrane domain receptors coupled to G proteins, G<sub>q/11</sub>. Three α<sub>1</sub>-receptor subtypes, which share approximately 75% homology in their transmembrane domains, have been identified: α<sub>1A</sub> (chromosome 8), α<sub>1B</sub> (chromosome 5), and α<sub>1D</sub> (chromosome 20). Terazosin is the first α<sub>1</sub>-receptor antagonist to demonstrate selectivity for the α<sub>1A</sub>-receptor. All three receptor subtypes appear to be involved in maintaining vascular tone. The α<sub>1A</sub>-receptor maintains basal vascular tone while the α<sub>1B</sub>-receptor mediates the vasocontrictory effects of exogenous α<sub>1</sub>-agonists. Activation of α<sub>1</sub>-receptors activates G<sub>q</sub>-proteins, which results in intracellular stimulation of phospholipases C, A<sub>2</sub>, and D. This results in mobilization of Ca<sup>2+</sup> from intracellular stores, activation of mitogen-activated kinase and PI<sub>3</sub> kinase pathways and subsequent vasoconstriction. Terozosin produces its pharmacological effects by inhibiting α<sub>1A</sub>-receptor activation. Inhibition of these receptors in the vasculature and prostate results in muscle relaxation, decreased blood pressure and improved urinary outflow in symptomatic benign prostatic hyperplasia.
  • toxicity: LD<sub>50</sub>=259.3mg/kg (IV in mice)
  • absorprion: Essentially completely absorbed in man (90% bioavailability).
  • halflife: 12 hours
  • roouteelimination: Approximately 10% of an orally administered dose is excreted as parent drug in the urine and approximately 20% is excreted in the feces.
  • volumedistribution:
  • clearance: