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phenobarbital (Rx)Brand and Other Names:

 
 
 

Dosing & Uses

AdultPediatric

Dosage Forms & Strengths

tablet: Schedule IV

  • 15mg
  • 16mg
  • 30mg
  • 32mg
  • 60mg
  • 64.8mg
  • 65mg
  • 100mg

elixir: Schedule IV

  • 20mg/5mL

injectable solution: Schedule IV

  • 30mg/mL
  • 60mg/mL
  • 65mg/mL
  • 130mg/mL
more...

Status Epilepticus

Typically used after benzodiazepines and phenytoin fail to abort status epilepticus

15-18 mg/kg IV loading dose infused at 25-60 mg/min; prepare to support ventilation; may repeat in 20-minute intervals PRN; not to exceed 30 mg/kg 

Seizures

All types of seizure disorders, including partial, tonic-clonic, and myoclonic seizures

1-3 mg/kg/day PO/IV in 1-2 divided doses initially; adjust accordingly to maintain within therapeutic serum concentration range 

Sedation

30-120 mg/day PO divided BID/TID; do not exceed 400 mg/day

Hypnotic

100-320 mg/day PO/IV/IM; do not administer for >2 weeks

Insomnia

100-200 mg PO qHS; do not exceed 400 mg/day

Dosing Considerations

Antiepileptic therapeutic concentration range: 10-40 mcg/L (43-172 micromoles/L)

Long half-life permits once-daily dosing, if tolerated, for seizures; single daily dosing at bedtime recommended because of sedation

Dosage Forms & Strengths

tablet: Schedule IV

  • 15mg
  • 16mg
  • 30mg
  • 32mg
  • 60mg
  • 64.8mg
  • 65mg
  • 100mg

elixir: Schedule IV

  • 20mg/5mL

injectable solution: Schedule IV

  • 30mg/mL
  • 60mg/mL
  • 65mg/mL
  • 130mg/mL
more...

Status Epilepticus

Infants and children: 15-20 mg/kg IV infused at a rate not to exceed 2 mg/kg/min; not to exceed 1000 mg/dose 

<60 kg: IV rate at <30 mg/min

May repeat with 5-10 mg/kg bolus dose after 15-30 min PRN; not to exceed cumulative dose of 40 mg/kg

Seizures

Neonates (<28 days): 3-5 mg/kg/day IV/PO in 1-2 divided doses

Infants: 5-6 mg/kg/day IV/PO in 1-2 divided doses

1-5 years: 6-8 mg/kg/day IV/PO in 1-2 divided doses

6-12 years: 4-6 mg/kg/day IV/PO in 1-2 divided doses

>12 years: 1-3 mg/kg/day IV/PO in 1-2 divided doses, OR 50-100 mg BID/TID

Sedation

2 mg/kg PO TID 

Hypnotic

3-5 mg/kg PO HS 

Preoperative Sedation

1-3 mg/kg PO/IV/IM 1-1.5 hours before procedure 

Hyperbilirubinemia (Off-label)

Neonates: 5 mg/kg/day PO/IV qDay, OR divided q12hr for 3-6 days following birth

<12 years (chronic cholestasis): 1.5-4 mg/kg PO q12hr 

Encephalopathy (Orphan)

Orphan designation for treatment of neonatal hypoxic ischemic encephalopathy to prevent seizures

Orphan sponsor

  • Fera Pharmaceuticals, LLC; 134 Birch Hill Road; Locust Valley, NY 11560

Dosing Considerations

<6 years: Potential toxic dose 8 mg/kg

Antiepileptic therapeutic concentration range: 15-30 mcg/L (43-129 micromoles/L)

Long half-life permits once-daily dosing, if tolerated, for seizures; single daily dosing at bedtime recommended because of sedation

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Interactions

Interaction Checker

phenobarbital and

No Results

     
     activity indicator 
    No Interactions Found
    Interactions Found

    Contraindicated

      Serious - Use Alternative

        Significant - Monitor Closely

          Minor

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            Adverse Effects

            Frequency Not Defined

            IV

            • Respiratory depression

            Common

            • Ataxia
            • Dizziness
            • Drowsiness
            • Dysarthria
            • Fatigue
            • Headache
            • Irritability
            • Nystagmus
            • Paresthesia restlessness
            • Vertigo
            • Geriatric patients: Excitement, confusion, depression
            • Pediatric patients: Paradoxical excitement/hyperactivity

            Less Common

            • Mental dullness
            • Constipation
            • Diarrhea
            • Nausea
            • Vomiting
            • Megaloblastic (folate-deficiency) anemia

            Uncommon

            • Rash
            • Hypocalcemia
            • Hepatotoxicity

            Rare

            • Stevens-Johnson syndrome
            • Rickets
            • Osteomalacia
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            Warnings

            Contraindications

            Hypersensitivity

            Porphyria

            Intra-arterial administration

            Severe hepatic impairment

            COPD

            Dyspnea

            Pregnancy/lactation

            Cautions

            Commercial injection is highly alkaline and may cause tissue necrosis if given SC or if it extravasates (if happens, treat with application of moist heat and injection of 0.5% procaine)

            May render OCPs ineffective

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            Pregnancy & Lactation

            Pregnancy category: D

            Lactation: Do not nurse

            Pregnancy Categories

            A:Generally acceptable. Controlled studies in pregnant women show no evidence of fetal risk.

            B:May be acceptable. Either animal studies show no risk but human studies not available or animal studies showed minor risks and human studies done and showed no risk.

            C:Use with caution if benefits outweigh risks. Animal studies show risk and human studies not available or neither animal nor human studies done.

            D:Use in LIFE-THREATENING emergencies when no safer drug available. Positive evidence of human fetal risk.

            X:Do not use in pregnancy. Risks involved outweigh potential benefits. Safer alternatives exist.

            NA:Information not available.

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            Pharmacology

            Mechanism of Action

            Depresses sensory and motor cortex, cerebellum

            Antiseizure activity occurs primarily where GABA mediates neurotransmission

            Hypnotic effects of barbiturates result from activity at GABA receptor in the polysynaptic midbrain reticular formation (controls CNS arousal)

            Off-label use for hyperbilirubinemia: Phenobarbital induces glucuronyl transferase and hepatic bilirubin-binding Y-protein to lower serum bilirubin concentrations

            Absorption

            Bioavailability: 70-90%

            Onset: 5 min (IV)

            Duration: 4-6 hr (IV/IM)

            Peak plasma time: 8-12 hr

            Therapeutic plasma concentration: 10-40 mcg/mL; may require 3-4 weeks of treatment to achieve therapeutic levels

            Distribution

            Protein bound: 20-45%

            Metabolism

            Metabolized by hepatic oxidative hydroxylation

            Metabolites: Inactive

            Enzymes induced: CYP1A2, CYP2B6, CYP2C19, CYP2C9/10, CYP3A4

            Elimination

            Half-life: 50-140 hr

            Excretion: Urine (major)

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            Administration

            IV Incompatibilities

            Additive: Chlorpromazine, ephedrine, hydralazine, hydrocortisone Na-succinate, hydroxyzine, insulin, levorphanol, meperidine, morphine, norepinephrine, pentazocine, procaine, prochlorperazine, promazine, promethazine, streptomycin, vancomycin

            Syringe: Hydromorphone, ranitidine, sufentanil

            Y-site: Amphotericin B cholSO4

            IV Compatibilities

            Solution: Dextrose Ringer, dextrose LR, dextrose saline, Ringer, LR, NS, ½ NS, Na-lactate 1/6 M, D5W, D10W

            Additive: Amikacin, aminophylline, CaCl2, Ca-gluconate, colistimethate, dimenhydrinate, meropenem, polymyxin B, thiopental, verapamil

            Syringe: Caffeine, heparin

            Y-site: Doxapram, enalaprilat, fentanyl, fosphenytoin gatifloxacin, hydromorphone (may be incompatible at high concentrations of both), levofloxacin, linezolid, meropenem, methadone, morphine SO4, propofol, sufentanil

            IV Administration

            Slow injection at <60 mg/min

            May be given IM into large muscle but not SC

            Commercial injection is highly alkaline and can cause local tissue necrosis

            Stability

            Store intact vials at room temperature, protected from light

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            Images

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            Formulary

            FormularyPatient Discounts

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            The above information is provided for general informational and educational purposes only. Individual plans may vary and formulary information changes. Contact the applicable plan provider for the most current information.

            Tier Description
            1 This drug is available at the lowest co-pay. Most commonly, these are generic drugs.
            2 This drug is available at a middle level co-pay. Most commonly, these are "preferred" (on formulary) brand drugs.
            3 This drug is available at a higher level co-pay. Most commonly, these are "non-preferred" brand drugs.
            4 This drug is available at a higher level co-pay. Most commonly, these are "non-preferred" brand drugs or specialty prescription products.
            5 This drug is available at a higher level co-pay. Most commonly, these are "non-preferred" brand drugs or specialty prescription products.
            6 This drug is available at a higher level co-pay. Most commonly, these are "non-preferred" brand drugs or specialty prescription products.
            NC NOT COVERED – Drugs that are not covered by the plan.
            Code Definition
            PA Prior Authorization
            Drugs that require prior authorization. This restriction requires that specific clinical criteria be met prior to the approval of the prescription.
            QL Quantity Limits
            Drugs that have quantity limits associated with each prescription. This restriction typically limits the quantity of the drug that will be covered.
            ST Step Therapy
            Drugs that have step therapy associated with each prescription. This restriction typically requires that certain criteria be met prior to approval for the prescription.
            OR Other Restrictions
            Drugs that have restrictions other than prior authorization, quantity limits, and step therapy associated with each prescription.
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