prevent a common, adverse effect of prolonged use of phenytoin sodium (Dilantin)

To prevent a common, adverse effect of prolonged use of phenytoin sodium (Dilantin), patients taking the drug are instructed to:

1- avoid crowds and obtain an annual influenza vaccination.
2- drink at least 2 L of fluids daily, including 8 to 10 glasses of water.
3- eat a potassium-rich, low sodium diet.
4- practice good dental hygiene and report gum swelling or bleeding.