ENTERAL FEEDS AND PHENYTOIN
A 70% reduction in phenytoin absorption has been described when it is given with enteral feeds (e.g. Isocal, Osmolite) administered via nasogastric tubes.
This interaction has been managed by giving the phenytoin diluted in water 2 hours after stopping the feed, flushing with 60 mL of water, and waiting another 2 hours before restarting the feed. However, one study found this method unsuccessful. Other suggestions include waiting 6 hours after the phenytoin dose before restarting the feed, stopping continuous feed 1 hour rather than 2 hours before and after phenytoin administration, the use of twice daily phenytoin or the use of intravenous phenytoin. Monitor the outcome carefully. The same problem can also occur when enteral feeds are given by the jejunostomy tube but methods to manage this are not yet established.
This interaction has been managed by giving the phenytoin diluted in water 2 hours after stopping the feed, flushing with 60 mL of water, and waiting another 2 hours before restarting the feed. However, one study found this method unsuccessful. Other suggestions include waiting 6 hours after the phenytoin dose before restarting the feed, stopping continuous feed 1 hour rather than 2 hours before and after phenytoin administration, the use of twice daily phenytoin or the use of intravenous phenytoin. Monitor the outcome carefully. The same problem can also occur when enteral feeds are given by the jejunostomy tube but methods to manage this are not yet established.