Phenobarbital

Phenobarbital is one of the oldest antiepileptic medicines in use. It is still, however, amongst the most widely used. It is used in most types ofepilepsyeven neonatal seizures.

How does phenobarbital work?

Like all the other antiepileptics, the mechanism of action of phenobarbital is on the GABA, or gamma-aminobutyric acid, receptors. This is a neurotransmitter involved in transmission of nerve impulses. Phenobarbital acts more specifically on the GABA-A receptor subgroup, increasing its activity and therefore countering the neuronal hyperactivity which is characteristic of epilepsy.

Do they have contraindications or precautions?

Phenobarbital has often been associated with a risk of drowsiness. It has a potent sedative action. It can also cause visual disturbance. It increases the risk of irritability or even hyperactivity in children.

Sources:

• Merck Manual, 4^th edition
• Institute of pharmaceutical and biological sciences – Lyon faculty of pharmacy.