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CARBAMAZEPINE IN PAEDIATRICS
By : Vijit Agrawal, B.Pharm
Pharm.D 5th Year
JSS College of Pharmacy,
Mysore - 570015
Doses Indicated in Epilepsy DOSE
AGE
DOSE FOR PAEDIATRICS
INITIAL DOSE MAXIMUM DOSE
< 6 Yrs 10-20 mg/kg/day PO q6hr Not to exceed 35 mg/kg/day
6-12 Yrs 50 mg PO q6hr Not to exceed 1000 mg/day
> 12 Yrs 200 mg PO q6hr Not to exceed 1000 mg/day
12-15 Yrs 200 mg PO q6hr Not to exceed 1200 mg/day
Drug should be taken with food.
Monitoring
• CBC• Blood chemistry• Kidney and liver function tests• Eye exams• Carbamazepine blood levels [ (4-12 mg/L) or
(16.9-50.8 micromoles/L) ]
Serious Interactions
• Tenofovir (Decreased level of Tenofovir)• Linezolid (Increase toxicity)• Selegiline (Increase toxicity)
ADRs
>10%
• Ataxia (15%) (lack of voluntary muscle movements)
• Dizziness (44%)• Drowsiness (32%)• Nausea (29%)• Vomiting (18%)
ADRs Cont…
1-10 %
• Dry Mouth (10%)
Rare• MI• Stevens-Johnson syndrome (HLA-B*1502)• TEN (HLA-B*1502) • Hepatic failure• Syndrome of inappropriate antidiuretic hormone secretion
(SIADH)
BLACK BOX WARNING
Contraindications
• Documented hypersensitivity• History of bone marrow suppression• Administration of MAO inhibitors within last 14 days• Coadministration with nefazodone (Decresed Level)• Coadministration with NNRTIs (Reduce NNRTI
serum concentration)• Jaundice, hepatitis• Pregnancy (especially first trimester: risk of fetal
carbamazepine syndrome)
Pregnancy & Lactation
• Pregnancy category : D• Lactation: Enters breast milk; not
recommended
D:Use in LIFE-THREATENING emergencies when no safer drug available. Positive evidence of human fetal risk.
Mechanism of Action
• Stabilizes inactivated state of sodium channels, thereby making neurons less excitable
Pharmacology
Absorption• Bioavailability: 85% (oral suspension) Distribution• Protein bound: 75-90%• Vd: 1.5 L/kg (neonates); 1.9 L/kg (children); 0.59-2 L/kg (adults) Metabolism• Via hepatic CYP3A4• Enzymes induced: CYP1A2, CYP2C9, CYP3A4 Elimination• Half-life: 25-65 hr (initial dosing); decreases to 10-20 hr after
autoinduction• Excretion: Urine (72%)
Pharmacogenomics
• It is estimated that 1 in 20 patients with HLA-B*1502 will have a severe dermatologic
reaction (eg, TEN, SJS) when taking carbamazepine.