Description of the medicine: Phenobarbital (Phenobaritalum)
Phenobarbital (Phenobaritalum). 5-Ethyl-5-phenylbarbituric acid.
Synonyms: Luminal, Adonal, Aephenal, Barbenyl, Barbinal, Barbiphen, Dormiral, Epanal, Episedal, Fenemal, Fenobarbital, Gardenal, Hypnotal, Lepinal, Luminal, Mephabarbital, Neurobarb, Nirvonal, Omnibarb, Phenobombitalonal, Omnibarb, Phenobombitalonal, Omnibarb, Phenobarbitonal, Smnibarbonal other
White crystalline powder, slightly bitter taste, odorless. Very little soluble in cold water, difficult to boiling (1:40), easily soluble in alcohol and alkali solutions.
Phenobarbital is usually considered a sleeping pill. Indeed, it has a pronounced hypnotic effect and is used in sleep disorders. However, at present, this drug is of greatest importance as an antiepileptic.
In small doses, phenobarbital has a calming effect and, in combination with other drugs (antispasmodics, vasodilators), is used in neurovegetative disorders.
In connection with the anticonvulsant effect, phenobarbital is also prescribed for chorea, spastic paralysis, and various convulsive reactions.
When administered, phenobarbital is completely, but relatively slowly absorbed. The peak concentration in the blood is observed 1 to 2 hours after administration. About 50% is bound by plasma proteins. The drug is evenly distributed in different organs and tissues; lower concentrations are found in brain tissue. The half-life in plasma in adults is 2 to 4 days (up to 7 days in newborns). It is released from the body slowly, which creates the prerequisites for cumulation. Metabolized by microsomal liver enzymes. The inactive metabolite (4-hydroxyphenobarbital) is excreted by the kidneys in the form of glucuronide, and about 25% - unchanged.
As a sleeping pill, phenobarbital is prescribed to adults in a dose of 0.1 - 0.2 g per reception, usually 1/2 to 1 hour before bedtime. The duration of sleeping pills is 6-8 hours. Children, depending on age, are prescribed from 0.005 to 0.0075 g.
The hypnotic effect of phenobarbital is similar to that of other barbiturates. An undesirable property of phenobarbital is that with its use a pronounced aftereffect can be observed: general depression, continued drowsiness, nystagmus, ataxia, etc.
As a sedative and antispasmodic, phenobarbital is prescribed at a dose of 0.01-0.03 - 0.05 g 2 to 3 times a day. It is usually used in combination with antispasmodic, vasodilator and other drugs (see Andipal, Bellataminal, Teofedrin tablets, etc.). It is part of the preparations of corvalol and valocordin.
Prolonged use of pheno6arbital and its preparations as sleeping pills and sedatives should be avoided due to the possibility of their cumulation and development of addiction.
Recently, a number of ready-made dosage forms containing phenobarbital (Pyraminal, Diaphein, Lupaverine, Theodinal, Microiod with Phenobarbital tablets, etc.) have been excluded from the range of medicines.
For the treatment of patients with epilepsy, phenobarbital was first used in 1912.