What is the effect of metabolism on D5W after administration?

• A. Becomes hypotonic after metabolism.
• B. Cannot be used as IV fluid.
• C. Remains isotonic indefinitely.
• D. Becomes hypertonic after metabolism.

Answer: (A)

D5W starts out isotonic with body fluids because the 5% dextrose provides osmoles comparable to plasma. But once the dextrose is rapidly metabolized by cells (to CO2 and water), there are few or no remaining osmoles in the solution. What’s left is essentially free water, so the solution becomes hypotonic relative to the body's fluids. Water then shifts into cells to balance the osmotic gradient, which is why D5W is considered hypotonic after metabolism. This is why the statement that it becomes hypotonic after metabolism is the best description. The other options don’t fit because D5W can be used safely as IV fluid in many contexts, it does not stay isotonic indefinitely, and it does not become hypertonic after metabolism.