Epilepsy is a neurological disorder
characterized by short, recurrent and
periodic attacks of motor, sensory or
psychological malfunction. It is associated
with paroxysmal abnormal electrical
discharge in the brain. According to Jackson,
epilepsy is due to sudden, excessive and
rapid discharge in the grey matter of the
brain. Anti-epileptic drugs inhibit the spread
of abnormal electrical discharge in the brain
with minimal general depressant action on
the central nervous system.
The antiepileptic drugs belong to
following groups as classified in table 2.6.1.
BARBITURATESPHENOBARBITONE
Phenobarbitone raises the threshold of
electro-shock seizures and modifies
maximal electro-shock seizures and abolish
the tonic phase thus useful in the treatment
of grandmal epilepsy. The threshold of
pentylenetetrazol induced convulsion is
slightly raised and has less usefulness in the
treatment of petitmal epilepsy.
Phenobarbitone has long plasma half-
life but slow oral absorption, is metabolized
in liver as well as excreted unchanged in
urine.
Phenobarbitone is useful in grandmal,
focal and temporal lobe epilepsy and
sometimes petitmal also. It is also useful in
the treatment of febrile convulsions.
Phenobarbitone is cheap and produces
less side effects which include sedation,
behavioural abnormalities, mental confu-
sion, impairment of learning and memory
and hyperactivity in children.MEPHOBARBITONE
It is N-methylphenobarbitone. It is more
expensive than phenobarbitone and requires
double dose compared to phenobarbitone.
It probably offers no advantage over
phenobarbitone.PRIMIDONE
Chemically it is deoxybarbiturate (carbo-
nyl oxygen of urea moiety in phenobarbitone
is changed by two hydrogen atoms) and is
twice as active as phenobarbitone in modify-(Mode of Action of Drugs)