Phenobarbitone Sodium inj
Indications
Phenobarbitone Sodium inj is used for:
Status epilepticus, Partial seizures, Sedation, Generalised tonic-clonic seizures, Hypnotic, Preoperative sedation
Adult Dose
Parenteral
Status epilepticus ; Emergency management of acute seizures
Adult: As phenobarbital Na: 200-600 mg. OR 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
As a hypnotic
Adult: 100-320 mg. Do not admin for >2 wk for the treatment of insomnia.
Intramuscular
Preoperative sedation
Adult: As phenobarbital Na: 100-200 mg 60-90 min pre-op.
Hepatic impairment: Reduce dose. Severe: Contraindicated.
Child Dose
Parenteral
Status epilepticus ; Emergency management of acute seizures
Child: As phenobarbital Na: 100-400 mg. OR
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 in 1-2 divided doses
1-5 years: 6-8 mg/kg/day in 1-2 divided doses
6-12 years: 4-6 mg/kg/day in 1-2 divided doses
>12 years: 1-3 mg/kg/day in 1-2 divided doses, OR 50-100 mg BID/TID
Intramuscular
Preoperative sedation
Child: As phenobarbital Na: 16-100 mg 60-90 min pre-op.
Intravenous
Preoperative sedation
Child: 1-3 mg/kg pre-op.
Renal Dose
Renal impairment: Reduce dose. Severe: Contraindicated.
Administration
Reconstitution:
Dilute w/ most IV infusion soln (e.g. NaCl 0.45% or 0.9%, lactated Ringer's, dextrose 5%, Ringer's).
IV Administration
Slow injection at <60 mg/min
May be given IM into large muscle
Contra Indications
Severe renal and hepatic disorders. Severe respiratory depression, dyspnoea or airway obstruction; porphyria. Pregnancy.
Precautions
Patient w/ history or sedative/hypnotic addiction; resp disease, depression or suicidal tendencies, hypoadrenalism. Avoid abrupt withdrawal. Mild to moderate renal and hepatic impairment. Elderly or debilitated patient, childn. Pregnancy and lactation. Patient Counselling May impair ability to drive or operate machinery. Monitoring Parameters Monitor CBC, LFTs, mental status and seizure activity.
Lactation: Do not nurse
Pregnancy-Lactation
Interactions
May enhance the hepatotoxic potential of paracetemaol overdoses. May decrease levels/effects of various CYP isoenzyme substrates e.g. teniposide, methotrexate, antipsychotics, beta-blockers, calcium-channel blockers, other anticonvulsants, chloramphenicol, cimetidine, corticosteroids, ciclosporin, doxycycline, oestrogens, felbamate, griseofulvin, tacrolimus, furosemide, methadone, oral contraceptives, theophylline, TCAs, warfarin. May reduce effects of guanfacine. Reduced metabolism and or increased toxicity with chloramphenicol, felbamate, MAOIs, valproic acid. May enhance the nephrotoxic effects of methoxyflurane.
Potentially Fatal: Additive sedation and/or respiratory depression with ethanol, sedatives, antidepressants, opioid analgesics, benzodiazepines and other CNS depressants. May decrease levels/effects of antiarrhythmic drugs e.g. disopyramide, propafenone, quinidine.
Adverse Effects
Side effects of Phenobarbitone Sodium inj :
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
Potentially Fatal: Stevens-Johnson syndrome.
Mechanism of Action
Phenobarbitone is a short-acting barbiturate. It depresses the sensory cortex, reduces motor activity, changes cerebellar function, and produces drowsiness, sedation and hypnosis. Its anticonvulsant property is exhibited at high doses.