Which drug should be withheld before hemodialysis?

• A. Phosphate binders
• B. Antibiotics
• C. Insulin
• D. Cardiac glycosides

Answer: (D)

The key idea is timing around dialysis based on how a drug behaves with the dialysis process. Cardiac glycosides, such as digoxin, have a narrow therapeutic window and are not effectively removed by hemodialysis because they distribute widely into body tissues and bind minimally to plasma proteins. More importantly, dialysis can cause shifts in electrolytes, especially lowering potassium, which increases the heart’s sensitivity to digoxin and raises the risk of toxicity. Because the drug won’t be cleared by dialysis and its toxicity risk can be amplified during the procedure, it’s prudent to withhold it before hemodialysis.

Phosphate binders, antibiotics, and insulin each have different considerations around dialysis, but they are not universally held before every session. Their management depends on the specific drug’s dialyzability, dosage, and the patient’s glucose and electrolyte status.