Which medication is removed by dialysis relatively easily?

• A. Furosemide
• B. Heparin
• C. Digoxin
• D. Acetaminophen

Answer: (C)

Dialysis removes drugs best when they are small, water-soluble, not heavily bound to proteins, and have a small distribution into tissues. Acetaminophen fits these properties: it has a small molecular weight, high water solubility, low protein binding, and a relatively limited distribution into tissues, so it is cleared more readily by dialysis.

Furosemide binds strongly to albumin and tends to distribute into tissues, making it difficult for dialysis to remove. Heparin is a large molecule with a high molecular weight, not easily dialyzed. Digoxin has a small molecular weight but a very large volume of distribution and extensive tissue binding, so only a small portion is present in the bloodstream for dialysis to remove, making it less dialyzable.