Cardiac Pharmacology: Digoxin and Phosphodiesterase Inhibitors

Vocabulary flashcards detailing mechanism of action, key numbers, adverse effects, toxicity, nursing considerations, and patient teaching for digoxin and phosphodiesterase inhibitors.

Digoxin

A cardiac glycoside used to treat heart failure by inhibiting the $Na^+/K^+$ pump, thereby increasing intracellular $Ca^{2+}$ to create stronger contraction and slower heart rate.

Therapeutic level of Digoxin

$0.5\text{--}1\,ng/mL$ (characterized by a half-life of $36\text{--}48\,h$ and a narrow therapeutic index).

Side effects of Digoxin

Anorexia, N/V, diarrhea, bradycardia, headache, and blurred vision.

Digoxin toxicity

Manifestations including N/V, anorexia, PVCs/dysrhythmias, bradycardia, yellow halos, double vision, and confusion.

Digoxin immune Fab

The specific antidote administered for digoxin toxicity.

Nursing considerations for Digoxin

Assess apical pulse first; hold the dose and report if heart rate is $<60$ or irregular, and monitor $K^+$ levels.

Drug interactions with Digoxin

Diuretics and cortisone lower $K^+$ (increasing toxicity); low $Mg^{2+}$ also increases the effect of the medication.

Patient teaching for Digoxin

Instruct the patient to take as prescribed, check their pulse, eat $K^+$-rich foods, avoid herbal supplements, and ask a healthcare provider before taking OTC medications.

Phosphodiesterase inhibitors

A class of positive inotropes used for heart failure that increases contractility and produces vasodilation.