MedicinecontrolledEssential

Phenobarbital/ phenobarbitone

A barbiturate used as a sedative and to treat seizures.

Clinical information

Common uses

generalized and partial seizures
sedation

Common side effects

drowsiness
sluggishness or 'hangover' feeling
dizziness
feeling sick or vomiting
headache

Cautions

may be habit forming — do not stop suddenly after long use
not for people with porphyria or severe liver or breathing problems
linked to thinking problems in children treated for febrile seizures
can harm an unborn baby and cause newborn withdrawal

Interactions

alcohol and other sedatives (additive drowsiness)
warfarin and oral anticoagulants (less effective)
oral contraceptives and hormones (less effective)
corticosteroids (less effective)
valproate (raises phenobarbital levels)
MAOI antidepressants (prolong its effects)

Pregnancy: avoid — can harm the baby; talk to your doctor

Reference information, not medical advice — always follow your doctor or pharmacist. Source: DailyMed, dailymed.nlm.nih.gov, phenobarbital label, setid 3e7637d9-2a8a-4063-8b14-1d1444629a15 (accessed 2026-08-16)

Approved brands & formulations16

Brand name	Dosage form	Strength	Importer	Category
Fenobarb	Parenteral ( Injection )	200mg/ml	authorized medicine importers	controlled
Gardenal	Oral Liquid	20mg/5ml	authorized medicine importers	controlled
Gardenal 30	Tablet	30 mg	authorized importers after registration of the product	controlled
Gardenal 60	Tablet	60mg	—	controlled
Neobital	Parenteral ( Injection )	200mg/ ml	authorized importers after registration of the product	controlled
Neobital	Parenteral ( Injection )	200mg/ ml	authorized importers after registration of the product	controlled
NEOBITAL	Parenteral ( Injection )	200mg (BP )/ml	—	controlled
Phenobarbital	Parenteral ( Injection )	30mg /2 ml	authorized medicine importers	controlled
Phenobarbital/ phenobarbitone	oral liquid	20 mg/5mL	MFDA designated importers with Pre Authorization approval before import	controlled
Phenobarbital/ phenobarbitone	Parenteral ( Injection )	200mg/ml	MFDA designated importers with Pre Authorization approval before import	controlled
Phenobarbital/ phenobarbitone	Tablet	30mg	MFDA designated importers with Pre Authorization approval before import	controlled
Phenobarbital/ phenobarbitone	Tablet	60mg	MFDA designated importers with Pre Authorization approval before import	controlled
Phenobarbitone	Suppositories ( Rectal )	50 mg	MFDA designated importers with Pre Authorization approval before import	controlled
Phenobarbitone	Parenteral ( Injection )	30mg /2 ml	MFDA designated importers with Pre Authorization approval before import	controlled
Phenobarbitone	Oral Liquid	20mg/5ml	MFDA designated importers with Pre Authorization approval before import	controlled
Phenylbarbit	Suppositories ( Rectal )	50 mg	authorized medicine importers	controlled