When the nurse administers a beta-adrenergic blocker to a patient with angina the nurse expects the drugs will help to control angina, but it also has what other effects?

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

The half-life of a drug refers to the time it takes for the plasma concentration of a drug to reduce by half. It is not a primary consideration when substituting generic drugs for brand-name drugs.

Choice B rationale

Critical concentration is the amount of a drug needed to achieve therapeutic effects. While important, it is not the main factor in generic substitution.

Choice C rationale

Distribution describes how a drug is dispersed throughout the body's tissues and fluids. This factor is crucial for drug efficacy but not directly related to substituting generic drugs.

Choice D rationale

Bioavailability is the degree and rate at which an active drug ingredient is absorbed and becomes available at the site of action. Generic drugs must have the same bioavailability as brand-name drugs to ensure they are just as effective.