A patient with atrial fibrillation has been prescribed digoxin (Lanoxin). The nurse should monitor which laboratory value to evaluate therapeutic effectiveness?

This is because metoprolol is a beta blocker, which can block the beta-2 receptors in the lungs and cause constriction of the airways.This can lead to breathing problems such as shortness of breath, cough, and wheezing. Bronchospasm is more likely to occur in people who have asthma or chronic obstructive pulmonary disease (COPD).

Choice A is wrong because tachycardia, or fast heart rate, is not an adverse effect of metoprolol. In fact, metoprolol can lower the heart rate by blocking the beta-1 receptors in the heart.A normal resting heart rate for adults ranges from 60 to 100 beats per minute (bpm).Metoprolol can cause bradycardia, or slow heart rate, which can be a serious side effect if it is too low.

Choice B is wrong because hyperglycemia, or high blood sugar, is not an adverse effect of metoprolol. Metoprolol does not affect the insulin secretion or glucose metabolism in the body.A normal blood sugar level for adults without diabetes is less than 140 mg/dL (7.8 mmol/L) two hours after eating. Metoprolol can cause hypoglycemia, or low blood sugar, in people who have diabetes and take insulin or other glucose-lowering medications.This is because metoprolol can mask the symptoms of hypoglycemia, such as palpitations and tremors.

Choice D is wrong because hyperkalemia, or high potassium, is not an adverse effect of metoprolol. Metoprolol does not affect the potassium balance in the body.

A normal blood potassium level for adults is 3.6 to 5.2 millimoles per liter (mmol/L)

Diuretics are drugs that increase the excretion of water and sodium by the kidneys, reducing blood volume and blood pressure.Diuretics lower blood pressure by dilating peripheral arterioles and decreasing blood volume by increasing the excretion of sodium and water.

Choice A is wrong because angiotensin-converting enzyme (ACE) inhibitors do not increase the excretion of water and sodium by the kidneys.ACE inhibitors block the conversion of angiotensin I to angiotensin II, a potent vasoconstrictor and stimulator of aldosterone secretion.By reducing angiotensin II levels, ACE inhibitors lower blood pressure by dilating blood vessels and decreasing sodium and water retention.

Choice C is wrong because adrenergic drugs do not increase the excretion of water and sodium by the kidneys. Adrenergic drugs act on the sympathetic nervous system, which regulates heart rate, blood pressure, and other functions. Depending on the type and location of adrenergic receptors, adrenergic drugs can have different effects on blood pressure. Some adrenergic drugs can increase blood pressure by stimulating alpha receptors, which cause vasoconstriction.Other adrenergic drugs can decrease blood pressure by stimulating beta receptors, which cause vasodilation and decreased cardiac output.

Choice D is wrong because direct acting vasodilators do not increase the excretion of water and sodium by the kidneys. Direct acting vasodilators are drugs that relax the smooth muscle of blood vessels, causing them to widen and lower blood pressure.Direct acting vasodilators do not affect the renin-angiotensin-aldosterone system or the sympathetic nervous system, which regulate sodium and water balance.