this presentation is based on anticonvulsants which are used to cure or to control the disturbance created in brain by abnormal discharging of neurons which is termed as epilepsy.
2. EPILEPSY AND ITS
TREATEMENT
SEIZURE- Seizure is a sudden discharge, sudden attack or sudden
symptoms which could be due to outburst of abnormal synchronous
discharging caused by a network of neurons.
Electrical discharge of neurons which may results into the type of
attacks or fits.
3. EPILEPSY
Two or more seizures occurring at intervals of 24 hours apart is termed to be
epilepsy.
It can result into lack or awareness or unconsciousness, major convulsions.
Types of epilepsy: there are two types of epilepsy
a) Grand mal epilepsy – it is the type of epilepsy in which a patient leads to
complete unconsciousness stage.
b) Petit mal epilepsy- it is the type of epilepsy in which only a part of body or
organ is affected.
4. CURE:
DRUGS used to cure epilepsy are called as anticonvulsants.
Anticonvulsants are basically the drugs that are used for controlling and
managing CNS disorders characterised by transient attacks of disturbed brain
function.
These drug basically having ureide structure (UREA like structure)
5. TYPES OF CONVULSANTS:
BARBITURATES
having cyclic ureides structure.
MODE OF ACTION: They impair the synaptic transmission and cause a
distinct enhancement of GABA ergic inhibitory response.
Barbiturates acts on the picrotoxin unit of GABA.(Y- amino butyric acid)
eg. Barbital , phenobarbital.
6. a) Barbital b) phenobarbital
Powerful hypnotic drug > it is used for both sedative and
hypnosis.
Therapeutic index is low >On metabolism it changes into
para hydroxyl phenLy derivative
(65%) and rest (35%) exerted as
such.
7. SAR OF BARBITEURATES
The number of carbon atoms in the side change should be between 4 to 10 for optimal therapeutic results.
One of the substituents at the side chain may be a close chain.
Inclusion of halogen atom in the side alkyl chain enhances the activity.
Inclusion of polar groups like hydroxyl, carbonyl, carboxylic ,amino and sulphonic in the side chain reduces
potency considerably.
Replacement of c=o group by c=s shows rapid action of drug but for short duration. Inclusion for more
sulphur atom decreases the activity.
Stereoisomers have more and same potencies.
Aromatic and alicyclic moieties exerts greater potency than corresponding aliphatic moiety having same
number of carbon atoms.
8. HYDANTOINS
Phenytoin sodium >mephenytoin
Dosage: 50 to 100 mg can give per
day.
it exerts its action on motor cortex
where it stabilises neuronal membrane
and thereby inhibits the spread of
seizure discharge.
9. OXAZOLIDINEDIONES
A) trimethadione. B) paramethadione
It is used in grand mal epilepsy and petit mal epilepsy.
It is useful when given in conjunction with phenytoin sodium or
phenobarbital.
It is metabolised by conversion to N-dimethylated compound which is more
soluble and in excreted as such without further degration.
10. SUCCINIMIDES
A) phensuximide b) methsuximide
• Used in petit mal epilepsy >used for curing petit mal epilepsy.
>more effective than phensuxinimide.
12. CHEMOTHERAPY OF EPILEPSY
it is very old disease and 1850s inorganic bromides were used for treating epilepsy.
In 1920s phenobarbital gave a meaningful treatment to epilepsy and again after 20
years 5 substituted hydantoins was found to substituted.
Salient structural features of anticonvulsants include the following:
a) Uriede type moiety structural variants.
b) Hydantoins having imidazole. 2-4 moieties moiety
c) Bezodiazepams having epoxide ring at c10-c11 position gives rise to active
metabolite.
