The nurse is providing patient teaching about prescribed opioid analgesic.
What is an important point related to a possible adverse effect of this drug?

Choice A rationale

Cardiac glycosides are not known for increasing heart rate. Instead, they tend to decrease heart rate by enhancing vagal tone and increasing the refractory period of the atrioventricular node, which helps in controlling heart rate, especially in atrial fibrillation.

Choice B rationale

Cardiac glycosides actually increase the force of myocardial contractions. They inhibit the sodium-potassium ATPase pump, which leads to an increase in intracellular sodium and calcium levels in the myocardial cells, thus increasing the force of contraction.

Choice C rationale

Cardiac glycosides do not significantly decrease conduction velocity. They primarily affect the contractility and heart rate but their influence on conduction velocity is relatively mild.

Choice D rationale

Cardiac glycosides improve renal blood flow and increase urine output by increasing the cardiac output and reducing the activation of the renin-angiotensin-aldosterone system. This helps in relieving symptoms of heart failure.

Choice A rationale

Class I antiarrhythmic drugs block sodium channels, affecting phase 0 of the action potential, not phase 3.

Choice B rationale

Class IV antiarrhythmic drugs block calcium channels, which affects phase 2 of the action potential and slows heart rate and conduction.

Choice C rationale

Class III antiarrhythmic drugs block potassium channels, prolonging phase 3 of the action potential. This results in a prolonged repolarization period, reducing the risk of arrhythmia.

Choice D rationale

Class II antiarrhythmic drugs are beta-blockers that primarily affect phase 4 of the action potential, reducing heart rate and conduction, but they do not block potassium channels.