phenobarbital (Luminal®)
Long acting barbiturate
Anticonvulsant
Sedative/Hypnotic
Phenobarbital is enhances the effects of the inhibitory neurotransmitter GABA and at high doses can act as a GABA analog. This increases membrane permeability to chloride, allowing increased chloride influx resulting in membrane hyperpolarization.
Sedative and hypnotic effects of barbiturates appear to be due primarily to interference with impulse transmission of the cerebral cortex by inhibition of reticular activating system.
Initially, REM sleep is suppresed but with chronic therapy, REM sleep returns to normal.
Limits the spread of seizure activity by increasing threshold for motor cortex activity.
Barbiturates are habid forming, although they do not produce analgesia.
3-30 minutes
4-6 hours
Prevention and treatment of seizure activity
Anxiety
Hypersensitivity
Patients with pophyria
Severe liver or respiratory disease
Hypotension
Bradycardia
Respiratory depression
CNS depression
Nystagmus
Nausea and vomiting
Burning at the site of injection
Other anticonvulsants, CNS depressants, and MAO inhibitors may potentiate effects.
65, 130 mg/ml ampule
IV: 200 - 600 mg up to 20 mg/kg
IV: 100 - 400 mg/kg (less than 1mg/kg/min)
Pregnancy Safety: Category B
Has potential for abuse
Carefully monitor vital signs and be prepared to assist ventilations as necessary.
Phenobarbital may be substituted for other barbiturates as a method of decreasing the incidence of withdrawal symptoms while weaning patients off barbiturates.
Use with caution in patients with pulmonary, cardiovascular, hepatic or renal insufficiency.
Hypoglycemic seizures should be treated with glucose, not phenobarbital, which will not resolve the hypoglycemic state or prevent CNS injury.
Use large, stable vein for injection (extravasation may cause tissue necrosis)