What is Phenobarbital - Meaning and definition

Published by Roberto Wenk. Reviewed by Alison Ramsey. Last updated date: January 23, 2019.

A long-acting barbituric acid derivative with antipsychotic property.
Phenobarbital binds to and activates the gamma-aminobutyric acid (GABA)-A receptor, thereby mimicking the inhibitory actions of GABA in the brain. The activation effects of the phenobarbital-receptor-ionophore complex include increased frequency of chloride channel openings, membrane hyperpolarization, and ultimately synaptic inhibition and decreased neuronal excitability. In addition, this agent inhibits glutamate induced depolarization.

National Cancer Institute. NCI Drug Dictionary. Internet. Accessed on September 15, 2009.

Published by Roberto Wenk. Reviewed by Alison Ramsey. Last updated date: January 23, 2019.

Adult
PO
Sedation 30-120 mg/day in 2-3 divided doses.
Hypnotic 100-320 mg. Do not admin for >2 wk for the treatment of insomnia.
Status epilepticus; emergency management of acute seizures 100-300 mg/day at bedtime.

IM
Pre-op sedation as phenobarbital Na: 100-200 mg 60-90 min pre-op.

IM/IV
Hypnotic 100-320 mg. Do not admin for >2 wk for the treatment of insomnia.
Status epilepticus; emergency management of acute seizures as phenobarbital Na: 200-600 mg.

Adverse drug reactions: bradycardia, syncope, hypotension; anxiety, agitation, ataxia, CNS excitation or depression, confusion, dizziness, drowsiness, hallucinations, hangover effect, headache, hyperkinesias; constipation, nausea, vomiting; agranulocytosis, thrombocytopenia; pain at inj site, thrombophlebitis (w/ IV use); respiratory depression, apnea (especially w/ rapid IV use), hypoventilation; gangrene (w/ unintentional intra-arterial inj).

Adapted from CIMS Drug Information System. Internet. Accessed on January 10, 2016.

Phenobarbital

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