Prescription under medical supervision

Therapeutic action

– Anticonvulsant, sedative and hypnotic


– Epilepsy: tonic-clonic (grand mal) and partial (focal) seizures

Forms and strengths

– 50 mg and 60 mg tablets


Follow national protocol.
For information:
– Child: initial dose of 3 to 4 mg/kg once daily or 1.5 to 2 mg/kg 2 times daily, increase to 8 mg/kg daily if necessary
– Adult: initial dose of 2 mg/kg once daily at bedtime (max. 100 mg daily), then, increase gradually if necessary, to the maximum dose of 3 mg/kg 2 times daily or 2 mg/kg 3 times daily 


– According to clinical response

Contra-indications, adverse effects, precautions

– Do not administer in respiratory depression.
– May cause: drowsiness, depression of the central nervous system.
– Do not stop treatment abruptly.
– Risk of increased sedation when combined with alcohol and drugs acting on the central nervous system such as diazepam, chlorphenamine, chlorpromazine, etc.
– Phenobarbital reduces the effectiveness of implants and oral contraceptives: use an intrauterine device (copper or levonorgestrel) or a progestogen-only injectable (medroxyprogesterone).
Pregnancy: avoid
Breast-feeding: avoid


– Phenobarbital is subject to international controls: follow national regulations.
– Plasma-concentrations are stable after 2 to 3 weeks. Caution: risk of accumulation.
– If necessary, phenytoin may be combined with phenobarbital.
– Also comes in 15 mg to 100 mg tablets.
– Storage: below 25 °C