Atropine Mechanism of Action Inhibits the actions of acetycholine on structures innervated by postganglionic sites (smooth/cardiac muscle, SA/AV nodes)
Atropine Indications First drug for symptomatic sinus bradycardia May be beneficial in AV block or asystole Second drug in asystole or slow PEA Organophosphate poisoning; large dose may be needed Precautions MI and hypoxia – atropine increases oxygen demand Avoid in hypothermia Not effective for 2 nd type II or new 3 rd degree block (may slow the rhythm) Doses < 0.5 mg may cause a paradoxical slowing
Atropine Asystole or slow (<60)PEA 1 mg IV/IO push Repeat every 3 to 5 minutes (if rhythm persists) to max. of 3 mg. Bradycardia 0.5 mg IV every 3-5 minutes as needed; max. of 3 mg. Use shorter dosing interval and higher doses in severe clinical situations Endotracheal Administration 2-3 mg diluted in 10 mL water or NS Organophosphate Poisoning Large doses (2-4 mg or higher) may be necessary Don’t delay pacing for severely symptomatic (unstable) patients.
Dopamine Mechanism of Action Stimulates adrenergic receptors; dose dependent.
Dopamine Indications Second-line drug for symptomatic bradycardia Hypotension with signs and symptoms of shock Precautions Correct hypovolemia with volume before initializing Use caution with cardiogenic shock and associated CHF May cause tachydysrhythmias; excessive vasoconstriction Don’t mix with sodium bicarbonate IV Administration Infusion at 5-20 mcg/kg/min. Titrate to patient response; taper slowly
Epinephrine Mechanism of Action Stimulates adrenergic receptors and is not dose dependent like dopamine.
Epinephrine Indications Cardiac arrest VF; VT; asystole; PEA Symptomatic bradycardia After atropine; alternative to dopamine Severe hypotension When atropine and pacing fail; hypotension accompanying bradycardia; phosphodiesterase enzyme inhibitors Anaphylaxis; severe allergic reactions Combine with large fluid volume; corticosteroids; antihistamines
Epinephrine Precautions May increase myocardial ischemia, angina, and oxygen demand High doses do not improve survival; may be detrimental Higher doses may be needed for poison/drug induced shock Dosing Cardiac arrest 1 mg (1:10,000) IV/IO every 3-5 min. High dose up to 0.2 mg/kg for specific drug OD’s Infusion of 2-10 mcg/min. Endotracheal of times normal dose SQ/IM mg
Adenosine Mechanism of Action Slows impulse formation in the SA node; slows conduction time through AV node; depresses left ventricular function and restores NSR.
Adenosine Indications 1 st drug for stable, narrow complex, regular SVT May consider for unstable SVT while preparing for cardioversion Wide-complex tachycardia thought to be, or determined to be reentry SVT Does not convert atrial fibrillation, atrial flutter, or VT Diagnostic maneuver; stable narrow-complex SVT
Adenosine Contraindications/Precautions Poison/drug induced tachycardia is contraindicated 2 nd and 3 rd degree block is contraindicated Transient side effects; flushing, CP, asystole, brady, ectopy Less effective with theophylline or caffeine If used for VT may cause worsening of clinical condition Transient periods of sinus brady or ventricular ectopy common after termination of SVT Safe in pregnancy
Adenosine Place supine or mild reverse Trendelenburg 6 mg rapidly followed by 20 mL flush May repeat at 12 mg every 1-2 minutes if unsuccessful
Diltiazem Mechanism of Action Inhibits calcium movement across cell membranes of cardiac and smooth muscle. Causes vasodilation, decreses heart rate and contractility, slows SA and AV conduction.
Diltiazem Indications Controlling ventricular rate in a-fib or flutter After adenosine to treat refractory reentry SVT if adequate blood pressure Contraindications/Precautions Do not use with wide-complex rhythms Do not use with poison/drug induced tachycardia Avoid in WPW Avoid in AV nodal blocks Blood pressure may drop from peripheral vasodilation
Diltiazem Rate control mg (0.25 mg/kg) IV over 2 minutes After 15 min. another mg (0.35 mg/kg) IV over 2 minutes, if needed Maintenance Infusion 5-15 mg/hour; titrated to physiologically appropriate heart rate
Metoprolol Mechanism of Action Selectively blocks beta-1 receptors, slowing sinus heart rate, decreasing cardiac output, and decreasing BP.
Metoprolol Indications Administer to all patients with suspected MI or unstable angina, absent contraindications Second-line agent for SVT refractory to adenosine To reduce myocardial ischemia in MI patients with elevated heart rate and/or blood pressure Emergency antihypertensive therapy for acute hemorrhagic or ischemic stroke
Metoprolol Contraindications/Precautions Hemodynamically unstable patients should not receive Signs of heart failure Low cardiac output Increased risk for cardiogenic shock Relative contraindications: 1 st, 2 nd, 3 rd degree blocks; active asthma; reactive airway disease; severe bradycardia; hypotension < 100 mmHg Concurrent administration of calcium channel blockers can cause serious hypotension Monitor cardiac and pulmonary status throughout
Amiodarone Mechanism of Action Prolongs myocardial cell action potential duration and refractory period by direct action on all cardiac tissue; decreases AV and SA conduction rates.
Amiodarone Indications Life threatening dysrhythmias VF/pulseless VT unresponsive to shock, CPR, and vasopressor Recurrent hemodynamically unstable VT Seek expert opinion for other uses Contraindications/Precautions Bradycardia 2 nd and 3 rd degree block Do not administer with meds that prolong QT interval (procainamide)
Amiodarone VF/VT – 300 mg IV/IO in mL NS. Can follow with ONE dose of 150 mg in 3-5 minutes, if needed. Life threatening dysrhythmias 150 mg over 10 minutes. May repeat every 10 minutes as needed.
Lidocaine Mechanism of Action Decreases depolarization, automaticity, and excitability of ventricle during diastole by direct action, reversing ventricular dysrhythmias.
Lidocaine Indications Alternative to amiodarone in VF/VT arrest Stable monomorphic VT Malignant PVC’s Can be used if Torsades is suspected Contraindications/Precautions Prophylactic use in AMI is contraindicated Reduce maintenance dose in liver impaired patients Discontinue infusion if toxicity develops
Lidocaine Cardiac Arrest Initial dose is mg/kg Refractory VF mg/kg in 5-10 min. Max 3 mg/kg Endotracheal dose 2-4 mg/kg Perfusing Dysrhythmia mg/kg up mg/kg dosing range. Repeat if necessary at lower range to total dose of 3 mg/kg Maintenance Infusion 1-4 mg/min
Magnesium Sulfate Mechanism of Action Increases magnesium levels in cases where prolonged QT interval is thought to be secondary to hypomagnesemia.
Magnesium Sulfate Indications Torsades is suspected in cardiac arrest Lfe-threatening ventricular dysrhythmias in digitalis OD Precautions Fall in BP with rapid administration Use caution in renal failure Dosing Arrest 1-2 g over 5-20 min. Torsades w/ pulse 1-2 g over 5-60 min.
Vasopressin Mechanism of Action Causes vasoconstriction with reduced blood flow, increasing core perfusion during cardiac arrest.
Vasopressin Indications Alternative to epinephrine in adult refractory VF/VT Alternative to epinephrine in asystole or PEA Contraindications/Precautions Potent peripheral vasoconstrictor (increased demand upon resuscitation) Dosing Single dose of 40 u that replaces either the 1 st or 2 nd dose of epinephrine. Epinephrine can be resumed 3-5 minutes after Can be used endotracheally; no suggested dose