Fosphenytoin Sodium

Generic Name: fosphenytoin sodium

Over-the-Counter (OTC)

Brand Names:

Fosphenytoin Sodium

11 DESCRIPTION Fosphenytoin sodium injection, USP is a prodrug intended for parenteral administration; its active metabolite is phenytoin. 1.5 mg of fosphenytoin sodium USP is equivalent to 1 mg phenytoin sodium, and is referred to as 1 mg phenytoin sodium equivalents (PE). The amount and concentration of fosphenytoin is always expressed in terms of mg PE . The pharmacological class of the fosphenytoin sodium is hydantoin derivative, and the therapeutic class is anticonvulsant.

Overview

11 DESCRIPTION Fosphenytoin sodium injection, USP is a prodrug intended for parenteral administration; its active metabolite is phenytoin. 1.5 mg of fosphenytoin sodium USP is equivalent to 1 mg phenytoin sodium, and is referred to as 1 mg phenytoin sodium equivalents (PE). The amount and concentration of fosphenytoin is always expressed in terms of mg PE . The pharmacological class of the fosphenytoin sodium is hydantoin derivative, and the therapeutic class is anticonvulsant.

Uses

1 INDICATIONS AND USAGE Fosphenytoin sodium injection is indicated for the treatment of generalized tonic-clonic status epilepticus and prevention and treatment of seizures occurring during neurosurgery. Fosphenytoin sodium injection can also be substituted, short-term, for oral phenytoin. Fosphenytoin sodium injection should be used only when oral phenytoin administration is not possible [see Dosage and Administration (2.4) and Warnings and Precautions (5.2) ] . Fosphenytoin sodium injection is indicated for the treatment of generalized tonic-clonic status epilepticus and prevention and treatment of seizures occurring during neurosurgery. Fosphenytoin sodium injection can also be substituted, as short-term use, for oral phenytoin.

Dosage

2 DOSAGE AND ADMINISTRATION • The dose, concentration, and infusion rate of fosphenytoin sodium injection should always be expressed as phenytoin sodium equivalents (PE) ( 2.1 ) • For Status Epilepticus: o Adult loading dose is 15 to 20 mg PE/kg at a rate of 100 to 150 mg PE/min ( 2.3 ) o Pediatric loading dose is 15 to 20 mg PE/kg at a rate of 2 mg PE/kg/min (or 150 mg PE/min, whichever is slower) ( 2.3 ) • For Non-emergent Loading and Maintenance Dosing: o Adult loading dose is 10 to 20 mg PE/kg given IV or IM; initial maintenance dose is 4 to 6 mg PE/kg/day in divided doses ( 2.4 ) o Pediatric loading dose is 10 to 15 mg PE/kg at a rate of 1 to 2 mg PE/kg/min (or 150 mg PE/min, whichever is slower); initial maintenance dose is 2 to 4 mg PE/kg every 12 hours at a rate of 1 to 2 mg PE/kg/...

Side Effects

6 ADVERSE REACTIONS The following serious adverse reactions are described elsewhere in the labeling: • Cardiovascular Risk Associated with Rapid Infusion [see Warnings and Precautions (5.2) ] • Withdrawal Precipitated Seizure, Status Epilepticus [see Warnings and Precautions (5.3) ] • Serious Dermatologic Reactions [see Warnings and Precautions (5.4) ] • Drug Reaction with Eosinophilia and Systemic Symptoms (DRESS)/Multiorgan Hypersensitivity [see Warnings and Precautions (5.5) ] • Hypersensitivity [see Warnings and Precautions (5.6) ] • Angioedema [see Warnings and Precautions (5.7) ] • Hepatic Injury [see Warnings and Precautions (5.8) ] • Hematopoietic Complications [see Warnings and Precautions (5.9) ] • Sensory Disturbances [see Warnings and Precautions (5.10) ] • Local Toxicity (Incl...

Interactions

7 DRUG INTERACTIONS Fosphenytoin is extensively bound to human plasma proteins. Drugs highly bound to albumin could increase the unbound fraction of fosphenytoin. Although, it is unknown whether this could result in clinically significant effects, caution is advised when administering fosphenytoin sodium with other drugs that significantly bind to serum albumin. The most significant drug interactions following administration of fosphenytoin sodium are expected to occur with drugs that interact with phenytoin. Phenytoin is extensively bound to serum plasma proteins and is prone to competitive displacement.

Warnings

WARNING: CARDIOVASCULAR RISK ASSOCIATED WITH RAPID INFUSION RATES The rate of intravenous fosphenytoin sodium injection administration should not exceed 150 mg phenytoin sodium equivalents (PE) per minute in adults and 2 mg PE/kg/min (or 150 mg PE/min, whichever is slower) in pediatric patients because of the risk of severe hypotension and cardiac arrhythmias. Careful cardiac monitoring is needed during and after administering intravenous fosphenytoin sodium injection. 5 WARNINGS AND PRECAUTIONS • Dosing Errors: Do not confuse the amount of drug to be given in PE with the concentration of the drug in the vial. Ensure the appropriate volume is withdrawn from the vial when preparing for administration. ( 5.1 ) • Withdrawal Precipitated Seizure: May precipitate status epilepticus. Dose reductions or discontinuation should be done gradually. ( 5.3 ) • Serious Dermatologic Reactions: Discontinue at the first sign of a rash, unless clearly not drug-related. If signs or symptoms suggest SJS/TEN, fosphenytoin sodium should not be resumed; consider alternative therapy. ( 5.4 ) • Drug Reaction with Eosinophilia and Systemic Symptoms (DRESS)/Multiorgan Hypersensitivity: If signs or symptoms of hypersensitivity are present, evaluate the patient immediately. 4 CONTRAINDICATIONS Fosphenytoin sodium is contraindicated in patients with: • A history of hypersensitivity to fosphenytoin sodium injection or its inactive ingredients, or to phenytoin or other hydantoins [see Warnings and Precautions (5.6) ] . Reactions have included angioedema.

Pregnancy

8.1 Pregnancy Pregnancy Exposure Registry There is a pregnancy exposure registry that monitors pregnancy outcomes in women exposed to antiepileptic drugs (AEDs), such as fosphenytoin sodium, during pregnancy. Physicians are advised to recommend that pregnant patients taking fosphenytoin sodium enroll in the North American Antiepileptic Drug (NAAED) Pregnancy Registry. This can be done by calling the toll-free number 1-888-233-2334, and must be done by patients themselves. Information on the registry can also be found at the website http://www.aedpregnancyregistry.org/.

Storage

16 HOW SUPPLIED/STORAGE AND HANDLING 16.1 How Supplied Fosphenytoin sodium Injection, USP is a clear, colorless to pale yellow solution supplied as follows: mg phenytoin sodium equivalents (PE) per vial Volume per vial (mL) Package Configuration NDC 500 mg PE/10 mL vial 10 mL per vial Package contains 10 vials of NDC 68462-945-10 NDC 68462-945-64 The 10 mL vials contain Tromethamine, USP (TRIS), H...

Frequently Asked Questions

What is Fosphenytoin Sodium used for?

1 INDICATIONS AND USAGE Fosphenytoin sodium injection is indicated for the treatment of generalized tonic-clonic status epilepticus and prevention and treatment of seizures occurring during neurosurgery. Fosphenytoin sodium injection can also be substituted, short-term, for oral phenytoin. Fosphenytoin sodium injection should be used only when oral phenytoin administration is not possible [see Dosage and Administration (2.4) and Warnings and Precautions (5.2) ] . Fosphenytoin sodium injection is indicated for the treatment of generalized tonic-clonic status epilepticus and prevention and treatment of seizures occurring during neurosurgery. Fosphenytoin sodium injection can also be substituted, as short-term use, for oral phenytoin.

What are the side effects of Fosphenytoin Sodium?

6 ADVERSE REACTIONS The following serious adverse reactions are described elsewhere in the labeling: • Cardiovascular Risk Associated with Rapid Infusion [see Warnings and Precautions (5.2) ] • Withdrawal Precipitated Seizure, Status Epilepticus [see Warnings and Precautions (5.3) ] • Serious Dermatologic Reactions [see Warnings and Precautions (5.4) ] • Drug Reaction with Eosinophilia and Systemic Symptoms (DRESS)/Multiorgan Hypersensitivity [see Warnings and Precautions (5.5) ] • Hypersensitivity [see Warnings and Precautions (5.6) ] • Angioedema [see Warnings and Precautions (5.7) ] • Hepatic Injury [see Warnings and Precautions (5.8) ] • Hematopoietic Complications [see Warnings and Precautions (5.9) ] • Sensory Disturbances [see Warnings and Precautions (5.10) ] • Local Toxicity (Incl...

Can I take Fosphenytoin Sodium during pregnancy?

8.1 Pregnancy Pregnancy Exposure Registry There is a pregnancy exposure registry that monitors pregnancy outcomes in women exposed to antiepileptic drugs (AEDs), such as fosphenytoin sodium, during pregnancy. Physicians are advised to recommend that pregnant patients taking fosphenytoin sodium enroll in the North American Antiepileptic Drug (NAAED) Pregnancy Registry. This can be done by calling the toll-free number 1-888-233-2334, and must be done by patients themselves. Information on the registry can also be found at the website http://www.aedpregnancyregistry.org/.

What are the important warnings for Fosphenytoin Sodium?

WARNING: CARDIOVASCULAR RISK ASSOCIATED WITH RAPID INFUSION RATES The rate of intravenous fosphenytoin sodium injection administration should not exceed 150 mg phenytoin sodium equivalents (PE) per minute in adults and 2 mg PE/kg/min (or 150 mg PE/min, whichever is slower) in pediatric patients because of the risk of severe hypotension and cardiac arrhythmias. Careful cardiac monitoring is needed during and after administering intravenous fosphenytoin sodium injection. 5 WARNINGS AND PRECAUTIONS • Dosing Errors: Do not confuse the amount of drug to be given in PE with the concentration of the drug in the vial. Ensure the appropriate volume is withdrawn from the vial when preparing for administration. ( 5.1 ) • Withdrawal Precipitated Seizure: May precipitate status epilepticus. Dose reductions or discontinuation should be done gradually. ( 5.3 ) • Serious Dermatologic Reactions: Discontinue at the first sign of a rash, unless clearly not drug-related. If signs or symptoms suggest SJS/TEN, fosphenytoin sodium should not be resumed; consider alternative therapy. ( 5.4 ) • Drug Reaction with Eosinophilia and Systemic Symptoms (DRESS)/Multiorgan Hypersensitivity: If signs or symptoms of hypersensitivity are present, evaluate the patient immediately. 4 CONTRAINDICATIONS Fosphenytoin sodium is contraindicated in patients with: • A history of hypersensitivity to fosphenytoin sodium injection or its inactive ingredients, or to phenytoin or other hydantoins [see Warnings and Precautions (5.6) ] . Reactions have included angioedema.

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Medical Disclaimer

This drug information is for educational purposes only and should not replace professional medical advice. Drug information is sourced from the FDA National Drug Code Directory and Structured Product Labeling. Always consult with a healthcare provider before starting, stopping, or changing any medication.