Phenobarbital Sodium (phenobarbital sodium)
Last reviewed · Source: First Databank (FDB) drug data
Overview
Phenobarbital is a barbiturate-derivative anticonvulsant.
Phenobarbital is a barbiturate anxiolytic and sedative.
As an anticonvulsant, phenobarbital is used principally in the management of tonic-clonic (grand mal) seizures and partial seizures. Phenobarbital may be used as the initial drug, particularly in infants and young children, but more often is administered concomitantly with phenytoin or other anticonvulsants. In infants and young children, phenobarbital is effective in the prevention of febrile seizures.
Routine use of phenobarbital for long-term prophylactic treatment of febrile seizures in children is controversial; most clinicians recommend selective use of the drug in these children and a careful assessment of the potential risks versus benefits. Children with febrile seizures who may be at particular risk of future difficulties and for whom prophylactic therapy is probably indicated include those whose first febrile seizure occurs at an early age (i.e., at less than 18 months of age); those who exhibit substantial abnormalities in neurologic function at the time of the first febrile episode or who have a history of substantial developmental delays; those who have febrile seizures that are complex, persist for more than 15 minutes, have focal features, or occur in series with a combined duration of more than 30 minutes, including those in whom they occur as a recurrence; and those with a family (i.e., parents, siblings) history of afebrile seizures.
Generic name: phenobarbital sodium
Reference product & biosimilars
No reference, biosimilar or interchangeable associated with this drug.
Today’s intelligence on Phenobarbital Sodium
Indications
No indications are available for this drug.
Dosing
Dosage must be carefully and slowly adjusted according to individual requirements and response. When a patient is transferred to another anticonvulsant drug, the dosage of phenobarbital should be gradually reduced over a period of 1 week while, at the same time, therapy is instituted with a low dose of the replacement drug.
When phenobarbital is used in conjunction with mephobarbital, the dose of each drug should be one-half the full dose of the drug used alone. Phenobarbital should be withdrawn or dosage reduced slowly to avoid precipitating seizures or status epilepticus.
The usual oral dosage of phenobarbital for adults is 100-300 mg daily. The drug frequently is given at bedtime. There is no advantage in dividing the daily dosage because of the long half-life of phenobarbital. For children, the usual oral dosage is 3-5 mg/kg or 125 mg/m2 daily. For the prevention of febrile seizures, maintenance dosage of 3-4 mg/kg daily has been effective. A period of 2-3 weeks of therapy may be required to achieve full anticonvulsant effects.
For management of status epilepticus and other acute seizure states, phenobarbital sodium is administered parenterally in doses of 200-600 mg for adults and 100-400 mg for children. Since up to 30 minutes may be required for maximum effect, it is important to allow the anticonvulsant effect to develop before administering additional doses, in order to prevent overdosage. Some clinicians administer phenobarbital sodium IV until seizures stop or a total dose of 20 mg/kg has been given. IV injections should be discontinued as soon as the desired effect is obtained.
For further information on chemistry, pharmacology, pharmacokinetics, uses, cautions, acute toxicity, drug interactions, and dosage and administration of phenobarbital, see the Anticonvulsants General Statement 28:12. See also the Barbiturates General Statement 28:24.04 and see Phenobarbital 28:24.04.
Dosage of phenobarbital must be individualized for each patient. Total daily dose should not exceed 600 mg. Following chronic administration, the drug should be withdrawn slowly to avoid the possibility of precipitating withdrawal symptoms if the patient is physically dependent on the drug.
Phenobarbital is administered orally. Phenobarbital sodium is administered by IM or slow IV injection. Parenteral solutions prepared from sterile phenobarbital sodium powder, but not the commercially available injections, may also be injected subcutaneously. Subcutaneous injection or extravasation of the commercially available injections causes tissue irritation, which can result in local reactions varying in severity from slight redness and tenderness to necrosis. If such extravasation or inadvertent injection occurs, treatment that includes application of moist heat and injection of 0.5% procaine hydrochloride at the affected site has been recommended.
IV administration of the drug should be reserved for emergency treatment of acute seizure states; however, usefulness of the drug in these conditions is limited. (See Uses.) When the drug is administered IV, the patients should be hospitalized and under close supervision. The drug must be administered IV slowly at a rate not greater than 60 mg/minute. Inadvertent intra-arterial injection of commercially available phenobarbital sodium injections can cause spasm and severe pain along the affected artery, which can result in local reactions varying in severity from transient pain to gangrene. The injection should be stopped if the patient complains of pain or if signs of inadvertent intra-arterial injection occur, such as patches of discolored skin, a white hand with cyanosed skin, or delayed onset of action. The most appropriate therapy for such inadvertent injection has not been fully established, and the manufacturers' labeling should be consulted for current recommendations.
Patients who are currently receiving or beginning therapy with phenobarbital and/or any other anticonvulsant should be closely monitored for notable changes in behavior that could indicate the emergence or worsening of suicidal thoughts or behavior or depression. (See Cautions: Precautions and Contraindications, in the Anticonvulsants General Statement 28:12.)
IV administration of the drug should be reserved for emergency treatment of acute seizure states; however, usefulness of the drug in these conditions is limited. (See Uses.) When the drug is administered IV, the patient should be hospitalized and under close supervision. The drug must be administered IV slowly at a rate not greater than 60 mg/minute. Inadvertent intra-arterial injection of commercially available phenobarbital sodium injections can cause spasm and severe pain along the affected artery, which can result in local reactions varying in severity from transient pain to gangrene. The injection should be stopped if the patient complains of pain or if signs of inadvertent intra-arterial injection occur, such as patches of discolored skin, a white hand with cyanosed skin, or delayed onset of action. The most appropriate therapy for such inadvertent injection has not been fully established, and the manufacturers' labeling should be consulted for current recommendations.
No dosing information is available for this tab.
No dosing information is available for this tab.
Drug interactions
There is no enhanced messaging for this drug.
There are no contraindication interactions for this drug.
There are no severe interactions for this drug.
There are no moderate interactions for this drug.
Contraindications
There is no enhanced messaging for this drug.
There are no contraindication contraindications for this drug.
There are no severe contraindications for this drug.
There are no moderate contraindications for this drug.
Adverse reactions
There is no enhanced messaging for this drug.
There are no severe adverse reactions for this drug.
There are no less severe adverse reactions for this drug.
Precautions
Phenobarbital shares the toxic potentials of the barbiturates, and the usual precautions of barbiturate administration should be observed. (See Cautions in the Barbiturates General Statement 28:24.04.)
IV phenobarbital sodium may cause respiratory depression, particularly if the drug is administered too rapidly. The drug must be administered slowly at a rate not greater than 60 mg/minute, and personnel and equipment should be readily available for administration of artificial respiration.
No enhanced messaging available.
No enhanced messaging available.
No enhanced messaging available.
No enhanced messaging available.
ICD codes
No ICD codes are available for this drug.
Formulary status
Search health-plan coverage for this drug by ZIP code.
Choose the first character of a health plan name.
Last reviewed · Source: First Databank (FDB) drug data
On this page
Actions
Sign in to save favorites
Saving this drug requires a free Physicians Office Resource account.