• Seizure disorders

Sezaby Generic Name & Formulations

General Description

Phenobarbital sodium 100mg/vial; lyophilized pwd for IV infusion after reconstitution.

Pharmacological Class


How Supplied

Single-dose vial—1

Generic Availability


Mechanism of Action

The precise mechanism of action for phenobarbital for the treatment of neonatal seizures is not fully understood, but it is thought to involve potentiation of synaptic inhibition through an action on the GABAA receptor.

Sezaby Indications


Neonatal seizures in term and preterm infants.

Sezaby Dosage and Administration


Not applicable.


See full labeling. Give by IV infusion over 15mins into a large peripheral vein. First loading dose: 20mg/kg. If seizures persist or recur after initial loading dose, may give a second loading dose (preterm infants: 10mg/kg or 20mg/kg; term infants: 20mg/kg) no sooner than 15mins after the first loading dose. Max total loading dose: 40mg/kg. Maintenance dose (initiate 8–12hrs after the first loading dose): 4.5mg/kg/day given in 2 or 3 divided doses (1.5mg/kg every 8hrs or 2.25mg/kg every 12hrs) for up to 5 days. 

Sezaby Contraindications


Acute porphyrias.

Sezaby Boxed Warnings

Boxed Warning

Risks from concomitant use with opioids. Dependence and withdrawal reactions after use of Sezaby for a longer duration than recommended. Abuse, misuse, and addiction with unapproved use in adolescents and adults.

Sezaby Warnings/Precautions


Must be experienced in managing serious cardiorespiratory adverse reactions (including airway management). Dependence and withdrawal reactions. Avoid abrupt cessation if used for a longer duration than recommended; withdraw gradually. Not approved for use in adolescents or adults; unapproved use exposes them to risks of abuse, misuse, and addiction. Monitor for respiratory depression or insufficiency. Discontinue at the 1st sign of a rash, unless not drug related. If serious dermatologic reactions (eg, Stevens-Johnson syndrome [SJS] or toxic epidermal necrolysis [TEN]) signs/symptoms occur, do not resume and consider alternative therapy. Evaluate immediately if signs/symptoms of Drug Reaction with Eosinophilia and Systemic Symptoms (DRESS) or hypersensitivity reactions develop; discontinue if alternative etiology cannot be established. Avoid in those who are at significant risk of developing torsade de pointes (eg, congenital long QT syndrome, uncontrolled or significant cardiac disease, recent MI, HF, unstable angina, bradyarrhythmias, AV block, aortic stenosis, uncontrolled hypothyroidism); if unavoidable, obtain ECGs during treatment, monitor serum electrolytes and correct abnormalities. Avoid perivascular extravasation or intra-arterial injection. Discontinue if infusion site reactions occur. Embryo-fetal toxicity. Neonates exposed through breast milk; monitor.

Sezaby Pharmacokinetics


Primarily CYP2C9 and to a lesser extent by CYP2C19, CYP2E1, and UGTs.


Half-life: ~1 week.

Sezaby Interactions


Increased risk of sedation, respiratory depression, coma, and death with opioids or other CNS depressants; reserve concomitant use in those for whom alternative options are inadequate; limit dosages/durations to minimum required; monitor closely. Avoid concomitant drugs that may increase the QT prolongation risk or drugs that may potentiate phenobarbital; if unavoidable, monitor. Concomitant use with CYP2C9, CYP2C19, CYP2E1, UGT inhibitors or inducers may increase risk of adverse reactions or reduce efficacy; if unavoidable, consider titration and monitor closely. Antagonizes CYP3A, CYP2B6, CYP2C(s), UGTs substrates; if unavoidable, consider increasing substrate dose and monitor closely.

Sezaby Adverse Reactions

Adverse Reactions

Abnormal respiration, sedation, feeding disorder, hypotension; serious dermatologic reactions (eg, SJS, TEN, DRESS), hypersensitivity reactions, infusion site reactions.

Sezaby Clinical Trials

See Literature

Sezaby Note

Not Applicable

Sezaby Patient Counseling

See Literature