Hazards of administering phenytoin by enteral feeding tube:
(1) poor absorption, resulting in an increased risk for seizures
(2) increased absorption, resulting in toxicity
Factors associated with poor absorption:
(1) type of enteral feeding mixtures, especially some with high protein levels
(2) some generic preparations that may interact more with enteral feeding mixtures
Some enteral formulas that have been incompatible with phenytoin in past studies:
(1) Isocal
(2) Ensure and Ensure Plus
(3) Osmolite
(4) Jevity
Factors associated with increased risk for toxicity:
(1) increasing dose to compensate for decreased absorption
Recommendations:
(1) Set up a planned regimen to be followed precisely.
(2) Closely monitor any patient receiving phenytoin by enteral feeding, especially if there is any change in the regimen.
(3) Consider monitoring serum drug levels.
(4) Consider intravenous dosing if seizure control is critical.
(5) One option to minimize any interaction with an enteral diet is to stop the enteral feeding before and during administration of the phenytoin.
(6) Avoid unnecessary switching of the phenytoin preparation.
(7) Specifically check the compatibility of the enteral formula with phenytoin.
