Cerebyx - Fosphenytoin sodium

A pediatric patient was presented to the emergency room (ER) experiencing seizures for which 150-mg Cerebyx (fosphenytoin anticonvulsant) IV was ordered. The pharmacy technician took the call for Cerebyx and delivered three 10-mL vials of Cerebyx 50-mg PE (phenytoin sodium equivalents) per mL to the ER as a floor stock transaction. A nurse misread the 50-mg PE/mL on the 10-mL container label, making the assumption that the entire vial contained 50 mg PE. The contents of all three vials were prepared for administration. Instead of 150 mg PE, the patient was administered ten times the intended dose, or 1,500 mg PE. The patient later died. The ER staff only discovered the error after the patient s blood phenytoin levels were returned from the laboratory. 

Fosphenytoin is a prodrug, a compound that undergoes chemical conversion in the body to become the therapeutically active compound phenytoin. Cerebyx dosage will continue to be expressed in PEs. This terminology was adopted in an effort to simplify therapeutic conversions between phenytoin sodium and fosphenytoin sodium (i.e., 500 mg of phenytoin sodium injection is equal to 500 mg PE of fosphenytoin sodium injection). The manufacturer pointed out that by using PEs, prescribers will not have to make dosing... 

Hydantoins Ethotoin (Peganone) Fosphenytoin (Cerebyx) Mephenytoin (Mesantoin) Phenytoin (Dilantin) Primary effect is to stabilize membrane by blocking sodium channels in repetitive-firing neurons higher concentrations may also influence concentrations of other neurotransmitters (GABA, norepinephrine, others)... 

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