A nurse in a provider’s office is monitoring blood electrolytes for four clients who take digoxin.
Which of the following electrolyte values increases a client’s risk for digoxin toxicity?

Digibind is the trade name forantidigoxin, which is an antibody made up of anti-digoxin immunoglobulin fragments.It is thespecific antidoteto digoxin toxicity, which can occur even when the serum digoxin concentration is within the therapeutic range.Digoxin toxicity causes anorexia, nausea, vomiting, neurological symptoms and arrhythmias.

Choice A, Protamine sulfate, is wrong because it is the antidote for heparin overdose, not digoxin toxicity.

Protamine sulfate reverses the anticoagulant effect of heparin by binding to it and forming a stable complex.

Choice B, Acetylcysteine, is wrong because it is the antidote for acetaminophen overdose, not digoxin toxicity.

Acetylcysteine replenishes glutathione, which is depleted by acetaminophen metabolites that cause hepatotoxicity.

Choice D, Vitamin K, is wrong because it is the antidote for warfarin overdose, not digoxin toxicity.

Vitamin K restores the synthesis of clotting factors that are inhibited by warfarin.

Normal ranges for serum digoxin concentration are 0.6 to 1.2 nanomol/L (0.5 to 0.9 nanograms/mL) for heart failure and unknown for atrial fibrillation without heart failure.

Normal ranges for serum potassium level are 3.5 to 5.0 mmol/L and for serum magnesium level are 0.7 to 1.0 mmol/L.

Nitroglycerin is a medication that dilates the blood vessels and improves blood flow to the heart. It is used to treat angina, a condition that causes chest pain due to reduced oxygen supply to the heart. However, nitroglycerin can lose its effectiveness over time if it is used continuously. This is called tolerance, and it means that the patient will need higher doses of the medication to achieve the same relief. To avoid tolerance, patients who use transdermal nitroglycerin patches are instructed to remove the patch at bedtime and apply a new one in the morning. This creates a nitrate-free interval of about 8 to 12 hours, which allows the body to restore its sensitivity to nitroglycerin.

Choice A is wrong because an allergic response is not a common side effect of nitroglycerin. Some patients may experience skin irritation or rash at the site of application, but this is usually mild and does not require discontinuation of the medication.

Choice C is wrong because overdosage is unlikely with transdermal nitroglycerin patches. The patches deliver a controlled amount of nitroglycerin through the skin over a period of time. The risk of overdosage is higher with other forms of nitroglycerin, such as tablets or sprays, which are taken as needed for acute angina attacks.

Choice D is wrong because forgetting to remove the patch in the morning is not a serious problem. The patch will continue to deliver nitroglycerin until it is removed, but it will not cause harm to the patient. However, it may reduce the effectiveness of the next patch if there is no nitrate-free interval between them.