Cardiac Drugs

Cardiac Drugs

Vasodilators
1. Nitroprusside
  1. Indications: HTN and CHF without ischemia
  2. Side Effects: hTN, reflex tacky, cyanide toxicity
  3. MOA: direct smooth m. relaxation; decreases both preload and after load
  4. Toxicity if >1mg/kg is given in 2.5 hour period. Hallmark of cyanide toxicity: unexplained metabolic acidosis. Treatment: sodium nitrate, thiosulfate
2. Nitroglycerin
  1. Indications: myocardial ischemia, pHTN, systemic HTN
  2. Side Effects: hTN, arrhthmias, myocardial ischemia
  3. MOA: direct smooh muscle relaxation; primarily reduces preload
Alpha and beta agnoists
1. Epinephrine
  1. Indications: hTN, LV failure, bronchospasm
  2. Side effects: HTN, arrhythmias, myocardial ischemia
  3. Small doses (0.01-0.05mcg/kg/min: Beta2 - bronchodilation prominent 4ug/min: Beta 1 --> improved LV fxn 10-20ug/min - alpha + beta
  4. Other effects: decreases RBF, Increases CO and HR
2. Dopamine
  1. Indications: hTN, olifuria
  2. Side effects: HTN, tachycardia, arrhythmias, myocardial ischemia
  3. UNIQUE in its ability to increase contractility, renal BF and GFR
  4. Other: less arrhythmogenic than eli; only modest increase in HR; mix in D5Wto avoid inactivation of catechol with alkaline solution
  5. Dose effects: 1-2mcg/kg/min: dopaminergic, 2-10 beta, >10 alpha
3. Dobutamine
  1. Indications: heart failure
  2. Side Effects: HTN, tachy, arrhythmias, myocardial ischemia
  3. Selective beta 1 agonist - improves CO (esp if HR and SVR are high); dose dependent increases in CO without marked increases in HR or BP
Phosphodiesterase inhibitors: lead to increased c-AMP --> improved uptake, storage and release of Ca from SR
1. Amrinone
  1. Indications: short term CHF tx
  2. Side effects: thrombocytopenia, tachyphylaxis, hypoK, GI effects
  3. Increases cardiac index while decreasing SVR and cardiac filling pressures. HR unchanged/increases very slightly. DOES NOT increase myocardial oxygen consumption. Also enhances A-V conduction; patients with atrial arrhythmias should be pretreated with digitalis
2. Milrinone - enhanced vasodilatory properties compared to amrinone; causes greater decreases in LV pressure and BP than amrinone
Chronotropes - heart rate
1. Atropine - 0.5mg q2min, total 2mg
2. Isoproterenol: B1 + B2 - useful in 3rd degree block and EMD. PROBLEM: may decrease SVR and MAP while also increasing HR, contractility and myocardial O2 consumption

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	Created by abbey.g.herman almost 11 years ago