Which of the following drugs should be withheld before haemodialysis?

RAK Nursing Officer - 2019

Pharmacology

Easy

Appeared in: RAK Nursing Officer - 2019

Explanation

Antihypertensive drugs are withheld before hemodialysis to prevent intra-dialytic hypotension.
Hemodialysis removes a significant volume of fluid from the bloodstream, which inherently lowers blood pressure.
Administering a blood pressure-lowering medication before this fluid removal can cause a synergistic effect, leading to a dangerously sharp and sudden drop in blood pressure (hypotensive shock).
This is a standard safety protocol in dialysis units to ensure patient stability during the procedure.

Option A: Insulin is generally not withheld. Patients, especially those with diabetes, need insulin to manage their blood glucose levels. Withholding it could lead to hyperglycemia.
Option B: Calcium preparations, often used as phosphate binders (like calcium carbonate or calcium acetate), are typically taken with meals to bind dietary phosphate. They are not routinely withheld before dialysis.
Option C: While Digoxin is often held, it is not the best answer compared to antihypertensives. The reason for holding digoxin is the risk of toxicity if electrolyte levels, particularly potassium, drop during dialysis. Hypokalemia potentiates digoxin's effects.

Clinical Relevance

Nursing practice connection: This is primarily an exam-oriented knowledge point with limited direct bedside application, so retain Medication management for patients undergoing hemodialysis as background academic context rather than a clinical decision trigger.
A primary nursing responsibility in a dialysis unit is medication reconciliation and ensuring that appropriate medications are held to prevent complications.
Patient safety is paramount. Administering an antihypertensive before dialysis can lead to severe hypotension, causing the patient to become dizzy, lose consciousness, or require emergency intervention during treatment.
Nurses must educate patients on which medications to take and which to hold on dialysis days to ensure adherence and safety.

How to Approach the Question

First, identify the core of the question: It asks about a standard safety procedure related to hemodialysis and medication.
Think about the physiological process of hemodialysis: its main function is to filter waste and remove excess fluid from the blood.
Consider the primary effect of fluid removal: it reduces the overall blood volume, which leads to a drop in blood pressure.
Now, evaluate each option based on this physiological effect:
Antihypertensive: This drug also lowers blood pressure. Combining it with dialysis would cause an additive effect, risking severe hypotension. This is a direct and predictable interaction.
Insulin: This affects blood sugar, not directly blood pressure in this context.

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