• Phenytoin (Dilantin) is a second line therapy for the actively seizing patient 
  -Use only if Fosphenytoin (Cerebyx) is not available
  -First line: Lorazepam IV, Diazepam IV, Midazolam IM

• Dose → 20 mg/kg IV Rate
  - 1 mg/kg/min
  -Max rate of 50 mg/min
  -Geriatrics → 50 mg over 2-3 minutes

• Contraindications:
  -Pregnancy (Category D)
  -Sinus Bradycardia AV Block - 2nd or 3rd degree
• Feared Complication: If administered too quickly, can lead to fatal hypotension and cardiotoxicity

• Fosphenytoin (Cerebyx)
  -Prodrug of phenytoin
  -Dosed as Phenytoin Equivalents (PE) Dose → 20 PE/kg IV Rate → 150 PE/min

Take Home Points: 
-Phenytoin IV is a good second line agent for the actively seizing patient if benzodiazepines fail, but must be administered slowly (no faster than 50mg/min) due to risk of fatal hypotension and cardiac toxicity. 

-If you have Fosphenytoin available, use it! It is safer and can be administered faster than Phenytoin.

Source: 
Glauser, T., Shinnar, S., Gloss, D., Alldredge, B., Arya, R., Bainbridge, J., & ... Treiman, D. M. (2016). Evidence-Based Guideline: Treatment of Convulsive Status Epilepticus in Children and Adults: Report of the Guideline Committee of the American Epilepsy Society. Epilepsy Currents, 16(1), 48-61.