Which of the following is NOT an advantage of fosphenytoin over phenytoin?

• A. It can be given as an intramuscular injection.
• B. It causes less irritation to veins than phenytoin.
• C. It can be administered faster than phenytoin.
• D. It can be taken orally.

Answer: (D)

Fosphenytoin is a prodrug of phenytoin designed for parenteral use. Its water-solubility lets it be given by intramuscular injection and infused intravenously at faster rates with less vein irritation and fewer infusion-related problems than phenytoin, which is less soluble and more irritating to veins. It also reduces issues like precipitation during IV administration. However, fosphenytoin is not formulated for oral dosing; the oral form is phenytoin itself. So the statement about being taken orally is not an advantage of fosphenytoin.