Norepinephrine (3)Cardiac effects weak direct stimulation (B,) inhibition via reflex in vivo) Net result: little cardiac stimulates 180 NOrepinephrine mean Arterial 140 Pressure (mmHg 100 120 Heart Rate beats/min)80 60 6 Time(min
(3) Cardiac effects： weak direct stimulation (b1 ); inhibition via reflex (in vivo) Net result: little cardiac stimulates Norepinephrine 16
Norepinephrine Clinical uses (limited therapeutic value) (1)Shock used in early phase of neurogenic shock; small doses and short duration ( dopamine is better; replaced by Metaraminol间羟胺,α agonist and Ne releaser, weaker but longer effect) (2)Hypotension due to drug poisoning especially for chlorpromazine(氯丙嗪) (3) Hemorrhage in upper alimentary tract(上消化道) orally given after dilution 17
Clinical uses (limited therapeutic value) (1) Shock • used in early phase of neurogenic shock: small doses and short duration (dopamine is better; replaced by Metaraminol 间羟胺，α agonist and NE releaser, weaker but longer effect) (2) Hypotension due to drug poisoning • especially for chlorpromazine （氯丙嗪） (3) Hemorrhage in upper alimentary tract (上消化道) • orally given after dilution Norepinephrine 17
Norepinephrine Adverse effects (1)Ischemia and necrosis at the site of iv administration relieved by phentolamine(酚妥拉明, receptor antagonist (2) Acute renal failure avoiding larger doses and longer duration; monitoring urinary volume (3 Contraindication hypertension, arteriosclerosis, heart diseases, severe urinary volume t, microcirculation disorders 18
Adverse effects (1) Ischemia and necrosis at the site of iv administration - relieved by phentolamine (酚妥拉明， receptor antagonist) (2) Acute renal failure - avoiding larger doses and longer duration; monitoring urinary volume (3) Contraindication - hypertension, arteriosclerosis, heart diseases, severe urinary volume , microcirculation disorders Norepinephrine 18
a1 receptor agonists Phenylephrine(去氧肾上腺素) Methoxamine(甲氧明 Induces reflex bradycardia, used in hypotension under anesthesia and drug poisoning, paroxysmal supraventricular tachycardia Phenylephrine: Mydriasis: pupillary dilator muscles, no or less effect on intraocular pressure, short-acting(for several hours}; act as a nasal decongestant(鼻血管收缩 药 19
• Induces reflex bradycardia, used in hypotension under anesthesia and drug poisoning, paroxysmal supraventricular tachycardia ； • Phenylephrine: Mydriasis: pupillary dilator muscles, no or less effect on intraocular pressure, short-acting (for several hours); act as a nasal decongestant (鼻血管收缩 药) Phenylephrine (去氧肾上腺素) Methoxamine (甲氧明) 1 receptor agonists 19