Unit 5a

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Unformatted text preview: ming dose or loading dose – Otherwise would take at least one week to reach therapeutic levels. Side Effects or Toxic Effects Side • G.I. - loss of appetite, nausea, vomiting, diarrhea – Partly due to G.I. irritation; also may be due to toxicity – May take with food or immediately after food but absorption may be altered. • Visual - single color vision (yellow or green tinged vision), white halos around objects, blurred or double vision • Nervous irritability, restlessness, weakness, headache (usually not serious - cut dosage) • Arrhythmias - many kinds – watch ventricles – – – – Ventricular tachycardia (more ectopic beats) “Bigeminy" - indicates toxicity Ventricular fibrillations - most common cause of death A-V block - due to negative dromotropic effect Contraindications or Cautions Contraindications Note: precautions are relative. • Recent myocardial infarction – Prone to developing arrhythmias – Digitalis may have additive or synergistic effect • Ventricular tachycardia - may throw into fibrillation – Increased ectopic foci & automaticity • Partial heart block - may produce complete block – Pacemaker is better option • Cardioversion (electroshock) – May cause fibrillation that will not respond to further shocks • Calcium administration - Ca++ synergistic with digitalis - toxic effect • Potassium depletion - increases toxicity • Renal or hepatic disorders or older patient – Lower maintenance dose required Drug Interactions Drug • Phenobarbital – Causes increased degradation, thus decreased effect • Diuretics (Indirect Only) – Decrease K+ which increases digitalis toxicity • Calcium ion – Increase in Ca++ will increase toxicity Other Meds for Heart Failure: Other • ACE inhibitors are now recommended first for cases of heart failure • Diuretics often used to control edema • Beta Blockers (early only) – Slows progression in some patients – Later in disorder is contraindicated • Flosequinan (a fluoroquinolone)- uncommon – Approved 1993 for cases resistant to ACE inhibitors • Aldosterone blockers • – Aldosterone produced peripherally in heart & major vessels – Aldost...
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This document was uploaded on 02/07/2014.

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