Fosphenytoin and Phenytoin Loading Against the Label
Loading dose of fosphenytoin (in mg PE) or IV phenytoin for a chosen mg/kg, set beside the range on the FDA label.
Open the calculator → Runs in your browser. Data leaves only if you deliberately send a problem report from the interactive tool.
Example
- Drug: fosphenytoin (mg PE)
- Phenytoin sodium injection, mg
- Adult or pediatric
- Adult
- Status epilepticus (status) or non-emergent loading
- Status epilepticus
- Route: intravenous (iv) or intramuscular
- Intravenous
- Patient weight
- 70
- Weight unit
- kg
- Dose chosen, per kg
- 15
Result: 1,050 mg of phenytoin sodium injection (21 mL) over at least 21 minutes: the dose is within the label range.
The tool opens with these values already filled in. Replace them with your own.
What you enter
- Drug: fosphenytoin (mg PE), phenytoin sodium injection (mg), or the oral phenytoin load
- Adult or pediatric
- Status epilepticus (status) or non-emergent loading (non-emergent)
- Route: intravenous (iv) or intramuscular (im, fosphenytoin only)
- Patient weight
- Weight unit
- Dose chosen, per kg (mg PE/kg or mg/kg)
- Oral load: history of renal or liver disease?
- Bag volume for the infusion (optional)
How this is calculated
Citation
FDA labels on DailyMed: Cerebyx (fosphenytoin), section 2, Tables 1 to 3 (loading range, maximum rate, initial maintenance; 50 mg PE/mL; dilution; when to draw a level) and Phenytoin Sodium Injection (loading range, 50 mg/minute, dilution). Read the sources: Cerebyx label ↗, Phenytoin injection label ↗
A reference and educational tool. Not medical, legal, or financial advice, and not a substitute for clinician judgment.