高血压英文ppt精品课件hypertension emergencies

HYPERTENSION Emergencies Systolic B.P. usually 180 mmHg Begin Treatment! This is a Hypertensive Emergency Begin to look for other causes of symptoms Principles of Therapy Lower B.P. over hours Initial goal B.P. 160s/90s Too rapid lowering may cause dire consequences (CVA, MI) May take several days to get to reasonable levels Avoid medications that cannot be controlled (sublingual nifedipine) Hypertensive Emergencies: Treatment For most patients the greatest risk of treating a hypertensive emergency is the risk of accompanying hypotension. Treat with short acting, easily titratable, I.V. drug. Parenteral Drugs for Treatment of Hypertensive Emergencies Drug Dosage Onset Duration Adverse Effects Indic.(I) Contrain.(C) Vasodilators Nitroprus- side 0.3-10 mcg/kg/min IV infusion 1-2 min. 1-2 min. N/V,mus. twitch., cyanide, thiocyan. tox. intracran. pressure I: CHF, aortic dissect., catechol. C: hepatic, renal insuff. Nitrogly- cerin (IV) 5-100 mcg/kg/min 2-5 min. 3-5 min. HA, dizziness, vomit., methemglo. tolerance I: coronary dis., CHF C: CVA intracran. pressure Parenteral Drugs for Treatment of Hypertensive Emergencies Diazoxide (Hyperstat IV) 1-3 mg/kg (up to 150 mg) IV bolus, q5-15 min; repeat q4-24 hr as needed 2-4 min 3-12 hr Nausea, hypotension, flushing, tachycardia, hypergly- cemia, aggravation of angina, fluid retention C: Syndromes of coronary insufficiency, (unless used with beta- blocking agent), cerebrovascular accident, hypersensi- tivity to sulfonamides Parenteral Drugs for Treatment of Hypertensive Emergencies Fenoldopam mesylate (Corlopam) 0.1-1.7 micrograms/kg/min IV infusion 5-15 min 1-4 hr Headache, dizziness, flushing, increased intraocular pressure, hypokalemia, dose-related tachycardia I: Severe hyperten-sion with renal insuffi-ciency C: Glaucoma Hydralazine HCl (Apresoline) 10-20 mg IV or IM bolus, repeat q4-6 hr as needed (maximum dose, 40 mg) 10-20 min 3-8 hr Tachycardia, flushing, headache, vomiting, aggravation of angina I: CHF C: Coronary insufficiency, aortic dissection, cerebrovas- cular accident (may increase intracranial pressure) Parenteral Drugs for Treatment of Hypertensive Emergencies Enalaprilat (Vasotec I.V.) 1.25-5 mg q6 hr IV 15 min 6 hr Precipitous drop in blood pressure in high- renin states, variable response I: CHF C: Use with caution in patients with severe renal insufficiency (not receiving dialysis) Nicardipine HCl (Cardene) 5-15 mg/hr IV infusion 5-20 min 1-2 hr Tachycardia, headache, flushing, local phlebitis C: Greater than first-degree heart block, CHF Parenteral Drugs for Treatment of Hypertensive Emergencies Adrenergic Inhibitors Phentol- amine (Regitine) -blocker 5-20 mg IV, repeat as necessary 1-2 min 10-30 min Tachycardia, nausea, flushing, abdominal pain, aggravation of angina I: Catecholamine excess C: Syndromes of coronary insufficiency Esmolol HCl (Brevibloc) 200-500 micrograms/kg/min over 1-4 min, then 50-300 micrograms/kg/min IV infusion 1-2 min 10-20 min Hypotension, nausea, bradycardia or heart block, dizziness I: Syndromes of coronary insufficiency C: Greater than first-degree heart block, CHF Parenteral Drugs for Treatment of Hypertensive Emergencies Labetalol HCl (Normo- dyne, Trandate) - blocker 20-80 mg IV bolus, repeat as needed (maximu m dose, 300 mg); or 2 mg/min IV infusion 2-10 min 2-4 hr Hypoten- sion, nausea, itching, scalp tingling, dizziness I: Synd- romes of coronary insuffi- ciency, catechol- amine excess C: first- degree heart block, CHF, bronchial asthma Fenoldopam: Indications In-hospital, short-term (up to 48 hours) management of severe hypertension when rapid, but quickly reversible, emergency reduction of blood pressure is clinically indicated, including malignant hypertension with deteriorating end organ function. Transition to oral therapy with another agent can begin at any time after blood pressure is stable during fenoldopam infusion. Physiologic Effects Fenoldopam Systemic Vasodilation Does not cross BBB Coronary Vasodilation without “steal” (in animals) Reflex tachycardia Metabolized by conjugation No P450 interaction RBF Na excretion H2O excretion Maintains GFR during BP lowering Mesenteric vasodilation Mucosal PO2 (in animals) Fenoldopam Receptor Activity Selective peripheral dopamine-1 (DA1) receptor agonism Systemic vasodilation Regional vasodilation (especially renal) Renal proximal and distal tubular effects No binding to DA2 or beta-adrenergic receptors No alpha-adrenergic agonism, but is an alpha1 antagonist Does not cross blood brain barrier Mechanism of Action of Fenoldopam Fenoldopam infusion Selective stimulation of D1-dopamine receptors Adenylyl cyclase activation Increase in intracellular concentration of cAMP Vascular smooth muscle relaxation Vasodilation of renal arteries Vasodilation of coronary arteries Vasodilation of mesenteric arteries Vasodilation of systemic arteries Maintenance of blood flow to vital organs Decrease in systemic vascular resistance Decrease in blood pressure Direct increase in sodium excretion Fenoldopam Metabolism Metabolism via conjugation Metabolites pharmacologically inactive No cytochrome P450 interactions No known metabolic drug interactions 88% albumin bound Elimination: 90% urine, 10% feces No dose adjustment for renal or hepatic impairment t ( 5 min) Small volume of distribution Rapid attainment of steady state ( 30 min) Plasma concentrations proportional to dose No alteration in pharmacokinetics over 48 hr infusion Rapid elimination upon discontinuation Fenoldopam: Pharmacokinetics Predictable hemodynamic effect Rapid onset of effect Predictable dose response for lowering BP No rebound hypertension Fenoldopam: Pharmacodynamics Rapid, predictable, dose-dependent blood pressure decrease (without overshoot) Short t, rapid attainment of steady state titration Linear pharmacokinetics No cytochrome P450 interactions Dose-response curves well defined No dosing adjustment for pre-existing renal or hepatic impairment Increases renal blood flow and maintains GFR Ease of use Fenoldopam: Potential Benefits Fenoldopam: Adverse Events Headache Flushing Nausea Hypotension Hypokalemi a EKG Abnormalities Tachycardia Vomiting Dizziness Extrasystoles Dyspnea Nicardipine: Characteristics Dihydropyridine Reflex tachycardia Useful when -Blockers contraindicated Water soluble and light stable (allows for IV infusion) Slow onset and offset Arterial catheter not mandatory May accumulate Variable duration of hypertensive effect Good in patients with renal disease Nitroprusside Onset 1-4 min., half- life 1-2 min. 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