II. Indications
- Status Epilepticus
- Seizure Disorder and unable to take oral medications
III. Contraindications
- Pregnancy
- Cardiac conduction delays
IV. Mechanism
V. Dosing
- Dosed in Phenytoin equivalents (PE)
- Transition to oral Phenytoin as soon as possible
- Therapeutic serum level range: 10 to 20 mcg/ml
-
Status Epilepticus
- Dose: 15 to 20 PE mg/kg IV or IM (at 3 mg/kg/min up to 100 to 150 mg/min) up to 1000 mg maximum
- Avoid IM dosing if possible
- Non-Emergent Loading Infusion
- Dose: 10 to 15 PE mg/kg IV (at 2 mg/kg/min up to 100 to 150 mg/min) up to 1000 mg maximum
- Maintenance
- Follows loading dose by 12 hours (Status Epilepticus or non-emergent loading)
- For initial dosing only (later dosing should be based on serum levels)
- Start: 2 to 4 PE mg/kg infused slowly (1-2 mg/kg/min up to 100 mg/min) every 12 hours
- Subsequent dosing (based on serum levels)
- Dose 4 to 8 mg PE/kg/day divided every 12 hours based on serum levels
- Preferred over Phenytoin for Status Epilepticus
- Fosphenytoin can be infused with dextrose
- Fosphenytoin has lower risk of Arrhythmia (due to no Ethylene Glycol in base)
- Fosphenytoin may be given IM or delivered a faster IV rate (not tissue toxic)
VII. Adverse Effects
- See Phenytoin
- Severe Hypotension and Cardiac Dysrhythmias
- Infuse slowly
- Cardiac and hemodynamic monitoring during infusion
VIII. Drug Interactions
- See Phenytoin
IX. Resources
X. References
- (2022) Presc Lett, Resource #361206, Antiseizure Medications
- Olson (2020) Clinical Pharmacology, Medmaster Miami, p. 56-7
- Hamilton (2020) Tarascon Pocket Pharmacopoeia