11/23/2015 CARDIOVASCULAR DRUGS CARDIOVASCULAR DRUGS include medications that affect the heart an blood vessels as well as anticoagulant and antiplatelet agents that prevent clotting cardiac glycosides antiarrhythmic agents antihypertensives vasodilators antilipemic agents anticoagulants platelet inhibitors thrombolytics hematopoietic agents 1 11/23/2015 CARDIAC GLYCOSIDES (Digoxin) occur widely in nature or can be prepared synthetically act directly on the myocardium to increase the force of myocardial contractions primary treatment of heart failure in patients with symptoms that persist after optimization of treatment with an ACE inhibitor, a beta- adrenergic blocker and/or a diuretic sometimes used alone / in conjunction with other meds (calcium channel blockers) to slow the ventricular response in patient with atrial fibrillation / flutter heart failure – heart fails to adequately pump nutrients and O2 to the body tissues body attempts to compensate by retaining salt and fluid – may result in pulmonary and peripheral edema heart increases in size to compensate for the increased work load symptoms of heart failure – fatigue, weakness, dyspnea, cyanosis, increased heart rate, cough and pitting edema small % of pts develop atrial fibrillation complications include ischemic stroke and systemic embolism 2 11/23/2015 https://media.giphy.com/media/HkwWUJfE9R6fu/giphy.gif normal sinus rhythm tachycardia bradycardia in pts with heart failure – cardiac glycosides act by increasing the force of the cardiac contractions without increasing cardiac output (O2 consumption) cardiac glycosides also ↓ norepinephrine levels (elevated in heart failure and toxic to the heart) glycosides produce ↑ heart efficiency - heart beats slower, heart size shrinks and concurrent diuretic therapy ↓ edema most commonly used cardiac glycosides – digitalis products digoxin (Lanoxin) only product marketed for clinical use – can be admin orally and parenterally with an intermediate duration of action 3 11/23/2015 digoxin – narrow margin between effective therapy and toxicity careful monitoring of heart rate and rhythm monitoring (ECG – electrocardiograms), cardiac function, side effects and serum digoxin levels required to determine therapeutic maintenance dose check apical pulse before admin of drug - <60 bpm consult physician modification of dosage is based on individual requirements and response as determined by general condition, renal fxn, cardiac fxn dosage adjustments required when changing from tabs or IM therapy to elixir or IV therapy toxic side effects (common / important in blue) • anorexia, nausea, vomiting (early signs) – abdominal cramping, distention and diarrhea • headache, fatigue, lethargy and muscle weakness • vertigo, restlessness, irritability, tremors and seizures • visual disturbances (blurring, diplopia (double vision) or halos) • cardiac arrhythmias (bradycardia <60 pbm) • electrolyte imbalance – potassium (hyperkalemia / hypokalemia cause arrhythmias) • insomnia, confusion, and mental disorders (↑ older adults) 4 11/23/2015 treatment of toxicity • discontinue drug immediately • monitor electrolytes (hyper/hypokalemia (K+), hypomagnesemia (Mg2+), and hypercalcemia (Ca2+) • atropine for symptomatic bradycardia • DigiFab (digoxin specific Fab fragments) as antidote in life- threatening situations precautions / contraindications • severe pulmonary disease • hypothyroidism • acute MI, acute myocarditis, severe heart failure • impaired renal fxn; hypokalemia / hypomagesemia • arrhythmias not caused by heart failure • pregnancy / lactation • ↑ doses in older adults interactions of digoxin may occur with • antacids, cholestryramine, neomycin and rifampin (↓ absorption digoxin – admin far apart) • diuretics, calcium, corticosteroids (↑ chance arrhythmias) • macrolide / antiarrhythmics (quinidne / verapamil – potentiate digoxin toxicity) • adrenergics (epinephrine, ephedrine, isoproterenol - ↑ risk of arrhythmias) 5 11/23/2015 PATIENT EDUCATION Patients taking digoxin should be instructed regarding: • recognition and immediate reporting of side effects • hold (stop taking) medication if any side effects occur – consult physician • check heart rate (pulse) on regular basis • avoid taking other meds at same time without physician approval • avoid taking OTC meds (antacids / cold remedies) • avoid abrupt withdrawal after prolonged use – dose decreased gradually under physician supervision ANTIARRHYTHMIC AGENTS arrhythmia – any change from the normal sequence of the electrical impulses of the heart – too fast (tachycardia), too slow (bradycardia) or erratically (fibrillation) antiarrhythmic agents – variety of drugs that act in different ways to suppress various types of cardiac arrhythmias (atrial / ventricular tachicardias, atrial fibrillation / flutter, and arrhythmias that occur with digoxin toxicity, during surgery and anesthesia choice of agent is based on the careful assessment of many factors – type and frequency of arrhythmia; cardiac, renal or other pathologic condition; current signs and symptoms 6 11/23/2015 7 11/23/2015 the role of the healthcare provider is critical when evaluating cardiac arrhythmias– accurate and timely reporting of vital signs, pertinent observations regarding effectiveness of meds and adverse side effects, modification of precipitating causes adequate knowledge of drug action and effects, along with good judgment essential most drugs given to counteract arrhythmias have potential to lower BP and slow heart beat – look for signs of hypotension and bradycardia which can lead to cardiac arrest antiarrhythmic agents can worsen existing arrhythmias or cause new arrhythmias – careful monitoring essential arrhythmia detection / monitoring can include ECG rhythm strips and 24h Holter monitoring as indicted electrolyte monitoring – potassium / magnesium non-drug therapy can include a pacemaker or automatic implantable cardioverter-defibrillator (AICD – most effective treatment for pts with life-threatening ventricular tachycardia / fibrillation and pts who have survived cardiac arrest) 8 11/23/2015 Adenosine (Adenocard) injectable antiarrhythmic agent with multiple electrophysiological activities – complicate its placement into a single category restores normal sinus rhythm in paroxysmal supraventricular tachycardia (PSVT - a faster than normal heart rate beginning above the heart's two lower chambers) by slowing the conduction time through the atrioventricular (AV) node also has vasodilatory, antiadrenergic, and negative chronotropic ( rate) properties – act to cardiac O2 demand adenosine is equal in effectiveness to diltiazem / verapamil in converting PSVT but less likely to cause hypotension common side effects - flushing, lightheadedness, headache, dyspnea, and chest pressure contraindicated in pts with 2nd / 3rd degree heart block or synptomatic bradycardia (unless functioning artificial pacemaker present) 9 11/23/2015 Amiodarone (Cordarone) oral and injectable antiarrhythmic – approved for the treatment of refractory life-threatening ventricular arrhythmias despite problematic organ toxicity profile (black box warning) – widely used for preventing recurrence of atrial fibrillation considered broad spectrum antiarrhythmic with multiple and complex electrophysiological effects Amiodarone also relaxes both smooth and cardiac muscle - coronary and peripheral vascular resistance and systolic BP side effects ( with lower doses 200-400mg/d) (common / important in blue) nausea / vomiting, constipation, anorexia cardiac arrhythmias, induction / worsening heart failure, hypotension neurotoxicity (tremor, peripheral neuropathy, parasthesia (numbness / tingling in extremities) hyper / hypothyroidism visual disturbances (optic neuropathy / neuritis blindness) dermatological rxns (photosensitivity) hepatits (rare) 10 11/23/2015 precautions / contraindications apply to pts with 2nd / 3rd degree heart block marked with sinus bradycardia (severe sinus node dysfunction) and when bradycardia has caused syncope (loss of consciousness due to BP) – cardiogenic shock pts with thyroid disease (large amnt of iodine in amiodarone) iodine hypersensitivity older adults (susceptible to thyrotoxic and neurotoxic effects) interactions with amiodarone – numerous and significant warfarin (can cause serious, fatal bleeding if warfarin not reduced – effects may persist for months after d/c) certain fluoroquinolones, macrolide antibiotics, systemic azole antifungals (QT wave prolongation) certain antiarrhythmics, digoxin, phenytoin (amiodarone serum concentrations of drugs) protease inhibitors and grapefruit juice ( amiodarone conc); beta- blockers, calcium channel blockers, lidocaine (additive adverse cardiac effects) cholestyramine, pheytoin, rifampin ( amiodarone conc - pharmacologic effects 11 11/23/2015 Beta-adrenergic blockers (propranolol / Inderal) antiarrhythmetics that inhibit adrenergic (sympathetic - excite) nerve receptors action is complx – results can include membrane stabilization effect on the heart Inderal (propranolol) – non-selective beta-blocker – management of some cardiac arrhythmias and treatment of hypertension (HTN) and some forms of chronic angina Block beta2 receptors in the lungs – can lead to bronchospasms Lopressor (metoprolol) – selective beta1-agonist – may be used with caution in pts with lung conditions that cause bronchospasm note: β1 receptors – found primarily in heart – when stimulated cause an ↑ in rate and force of contraction