Key uses
Status epilepticus: Used to control prolonged, severe seizure activity of the tonic-clonic (grand mal) type.
Following neurosurgery: Administered to prevent seizures that can occur after brain surgery or a severe head injury.
Short-term replacement therapy: Used for patients who are unable to take their regular oral phenytoin medication, for example, before or after surgery.
Administration guidelines
Rate: Because of the risk of severe cardiovascular reactions, including dangerous heart arrhythmias and low blood pressure, the injection must be administered slowly.
Adults: A maximum rate of 50 mg per minute is recommended.
Pediatrics: The rate should not exceed 1 to 3 mg/kg/min or 50 mg per minute, whichever is slower.
Route: Intravenous (IV) is the preferred route for rapid therapeutic effect. Intramuscular (IM) injection is generally not recommended due to erratic absorption and potential for local tissue damage.
Monitoring: Careful monitoring of heart rate, blood pressure, and respiratory function is essential during and after administration.
Potential risks and side effects
Cardiovascular issues: Rapid infusion can lead to severe hypotension (low blood pressure) and heart problems. This is particularly risky for elderly or critically ill patients.
"Purple glove syndrome": A rare but serious complication at the injection site, characterized by swelling, discoloration, and pain, which can lead to severe tissue damage.
Serious skin reactions: In some cases, phenytoin can cause severe skin reactions, including Stevens-Johnson syndrome (SJS) and toxic epidermal necrolysis (TEN).
Nervous system side effects: Dose-related side effects can include dizziness, uncoordinated movements (ataxia), slurred speech, confusion, and drowsiness.
Drug interactions: Phenytoin can interfere with many other medications, including oral contraceptives, and alcohol consumption should be avoided.
Important considerations
Prescription only: Phenytoin injection is a prescription medication that is only to be administered by a trained healthcare professional in a hospital or clinical setting.
Switch to oral medication: Once a patient's seizures are under control, they are often transitioned to an oral form of phenytoin.
Pregnancy and breastfeeding: The medication is generally considered unsafe for use during pregnancy and breastfeeding and should only be used if the benefit outweighs the risk.
