Guidelines for phenytoin infusions

Until recently, phenytoin sodium injection was not recommended for dilution in intravenous fluids because insolubility results in precipitation of phenytoin acid. The formation of rod-shaped crystals primarily reflects the failure to maintain the pH of the admixture above 9.5 to 10. Investigations have clarified this problem and point out that stable solutions of phenytoin sodium can be prepared which are safe for intravenous infusion provided the injection is diluted in small volumes of 0.9 percent sodium chloride or Ringer's. Lactate injection and administered freshly prepared. Specific guidelines are suggested for the preparation and administration of phenytoin sodium infusions.