Phenobarbitone dosage in neonatal convulsions.

Abstract

SUMMARY In order to find the optimal dosage schedule of phenobarbitone for neonatal convulsions, four groups of patients were studied. Twelve infants (group 1) received a mean phenobarbitone dose of 9 5 mg/kg a day given intramuscularly for 3 days followed by 5-8 mg/kg a day given intramuscularly and then orally. Six infants (group 2) received a mean intravenous loading dose of 9 5 mg/kg followed by 6 8 mg/kg a day given intramuscularly or orally. Nine infants (group 3) received a mean loading dose of 14-9 mg/kg intravenously followed by a maintenance dose of 5 9 mg/kg a day. Thirteen patients (group 4) received a mean intramuscular loading dose of 15 2 mg/kg followed by 5 9 mg/kg a day. Blood samples were taken regularly and phenobarbitone levels were determined by gas liquid chromatography. A mean intravenous or intramuscular loading dose of 15 mg/kg of phenobarbitone safely achieved therapeutic levels within 2 hours of injection and high therapeutic levels were maintained with a dose of 6 mg/kg a day. Group 2. Six infants aged between 1 and 25 (mean 10-2) days and weighing between 1650 and 3580 (mean 3053) g received a mean loading dose of 9-5 mg/kg intravenously followed by a mean maintenance dose of 6-8 mg/kg a day given intramuscularly for at least the first 6 doses and then orally or intramuscularly. The first maintenance dose was given 12 hours after the end of the infusion. The aetiology of the seizures was: birth hypoxia 2; hydrocephalus and congenital heart disease 1; prematurity and intracranial haemorrhage 1; recurrent hypoxia due to tracheo-oesophageal fistula 1; idiopathic 1*.Group 3. Nine patients aged between 1 and 18 (mean 5-1) days and weighing between 1650 and 3980 (mean 3066) g received a mean loading dose of 14.9 mg/kg intravenously followed by a mean maintenance dose of 5-9 mg/kg a day given intramuscularly or orally in two divided doses. The aetiology of the seizures was: birth hypoxia 3; birth trauma and hypocalcaemia 2; congenital heart disease 2 (one with hypoparathyroidism and one with intracranial haemorrhage); intracranial haemorrhage 1; idiopathic 1*.Group 4. Thirteen patients aged between 1 and 22 (mean 5-5) days and weighing between 1520 and 4085 (mean 2891) g received a mean loading dose of 15*2 mg/kg given intramuscularly followed by a mean maintenance dose of 5.9 mg/kg a day given *Further clinical details are available on request.

Brief postnatal exposure to phenobarbital impairs passive avoidance learning and sensorimotor gating in rats

“…We employed a loading dose of 80 mg/kg on P7, followed by 40 mg/kg on P8 and P9. Loading doses are commonly used clinically for neonates [23–25]. Doses were selected based on pharmacodynamic equivalence.…”

Phenobarbitone for the Management of Neonatal Seizures - A Single Center Study

“…Thus studies based on abolition of clinical seizures, may have more external validity and generalisability in NICUs, especially in third world countries. [34]. Some claim better clinical control with doses of up to 40 mg/kg and serum levels above 180 μmol/L [11].…”

Concentrations plasmatiques de phénobarbital et posologie en fonction de l’âge

“…L'injection de doses fraction nées n'est pas à retenir car des concentrations efficaces ne sont obtenues qu'après 10 h [13] avec un état d'équilibre retardé au 2e [17] ou 3e jour [7]. De même, une DC inférieure à 20 mg/kg n'apporte pas les mêmes garanties d'efficacité [5,12,13,17]. Le traitement d'entretien est ensuite débuté après 24 h, voire 48 h [10] à une posologie égale ou inférieure à 5 mg/kg [13] car au-delà un surdosage est constaté au 4e jour [17].…”