Editing Medical-Surgical Nursing (section)

=== Selected Cardiac Medications ===

Digoxin increases contractility and slows conduction. The therapeutic serum level is roughly 0.5 to 2.0 ng/mL, with lower targets used in heart failure. Toxicity presents with anorexia, nausea, vomiting, visual disturbances such as halos or yellow-green vision, confusion, and bradycardia or new dysrhythmias. Hold the dose and notify the provider if the apical pulse is below sixty beats per minute in an adult, counted for a full minute. Hypokalemia potentiates toxicity.

Beta blockers reduce heart rate, contractility, and blood pressure. Hold and reassess for bradycardia or hypotension per parameters, do not stop abruptly because of rebound ischemia and hypertension, and be aware they can mask the tachycardia and tremor of hypoglycemia.

Angiotensin converting enzyme inhibitors cause a dry persistent cough, hyperkalemia, and rarely angioedema, which is an airway emergency. Monitor potassium and kidney function.

Warfarin is monitored by the international normalized ratio, with a usual therapeutic range of 2.0 to 3.0 for most indications; the antidote is vitamin K. Heparin is monitored by activated partial thromboplastin time at about 1.5 to 2.5 times control; the antidote is protamine sulfate. A platelet count that falls sharply after several days of heparin suggests heparin-induced thrombocytopenia, and all heparin must be stopped.