Common Cardiovascular Drugs

Inotropic agents Vasodilators Antiarrythmic agents

α receptors ↑ protein kinase C  ↑intracellular Ca  smooth muscle contraction β receptor ↑ intracellular cAMP  relax smooth muscle, increase cardiac muscle contractility

α1 : peripheral vascular contraction β1 : increase HR, contractility β2 : 主要vasodilation, bronchodilation; 次要increase HR, contractility

Inotropic agents

Dopamine 因dose (ug/kg/min)的不同而作用在不同的receptor上 1-3  dopaminergic (DA): ↑renal and mesenteric blood flow 3-10  β 為主: increase HR, contractility; decrease SVR, but increase PVR > 10  α 為主: increase SVR and PVR; decrease renal flow

Levophed ( norepinepherine) 以α為主，β1為輔 Increase SVR  increase BP; may increase contractility; increase PVR 4mg/400ml 0.01 ml/ml =10ug/ml Usual range for infusion: 0.05-0.3 ug/kg/min

Dobutrex (dobutamine) β為主 (尤其β1)，minimal α effects Increase HR, contractility; decrease SVR, PVR dobutamine is an inotrope but not a pressor ! Infusion dosage: 2-20 ug/kg/min

Milrinone (primacor) Phosphodiesterase inhibitor Inhibit cAMP to breakdown  increase intracellular cAMP concentration In cardiac muscle: increase contractility, HR In vascular smooth muscle: vasodilation; decrease SVR, PVR

Loading dose: 25-75 ug/kg over 1-10 min Infusion dose: 0.375-0.75 ug/kg/min

Bosmin (epinephrine) 因dose (ug/kg/min)不同著重於不同的receptor 0.01-0.03: β 0.03-0.15: β為主，α為輔 > 0.15: α為主，β為輔

For cardiac arrest: adult: 0 For cardiac arrest: adult: 0.5 -1 mg IV bolus pediatric : 5-15 ug/kg IV bolus may be given intratracheally in 1 -10 ml volume Severe allergic reaction or bronchospasm: 10 ug/kg

Vasodilators

Nitroglycerin Direct vasodilator, venous > arterial dilation Mainly preload reduction ; reduce PVR large dose > 10 ug/kg/min produce arteriolar dilation Relieve coronary spasm, increase coronary flow, decrease ischemia

IV bolus: 50-100 ug Infusion: 0.1 – 7 ug/kg/min Nitroderm

Trandate (labetalol) α blocker: β blocker = 1:7 decrease HR; decrease BP Long duration

Perdipine Ca channel blocker Arterial dilation, decrease SVR Mild myocardial depressant: minimal in clinical dosage

PGE1 Selectively dilate the ductus arteriosus in neonates and infants Potent pulmonary vascular vasodilating effects Infusion dosage: 0.05 – 0.4 ug/kg/min

Antiarrythmic agents

Isuprel (isoproterenol) Pure β effect Positive inotropic and chronotropic effects May decrease BP Infusion: 0.02-0.05 ug/kg/min

Esmolol Selective β1 blocker Decrease HR, BP IV: 0.25-0.5 mg/kg Infusion: 50-200 ug/kg/min Rapid elimination

Amiodarone Use in Af, SVT, ventricular arrthymia Loading: 150 mg IV for 10 min Infusion: max. 900-1200mg/24hr first 24 hr, 720mg/24hr next Potent vasodilating effects and negative inotropic effects