Pharmacology for Dentistry

106 Section 2/ Drugs Acting on CNS

ing electroshock seizures in the rats. It is ef-
fective against all type of seizures e.g.
grandmal epilepsy, psychomotor epilepsy,
focal and myoclonic epilepsy. It is not effec-
tive in petitmal epilepsy.

It is converted into phenobarbitone
and phenylethyl malonamide in the
liver, which actually produces the
antiepileptic actions. The common side
effects are anorexia, drowsiness, nausea,
leukopenia, osteomalacia and megalo-
blastic anaemia.

HYDANTOINS

DIPHENYLHYDANTOIN (PHENYTOIN)

In epileptic patients there is repetitive

detonation of normal brain cells during the

depolarisation shift and consists of synchronous

and unusually large depolarisation on which

action potentials are superimposed. Phenytoin

prevents repetitive detonation of these normal

brain cells as it has a stabilizing influence on

the neuronal membrane. It is achieved by

prolonging the inactive state of voltage sensitive

Table 2.6.1: Classification of antiepileptic drugs

I. Barbiturates

Phenobarbitone (PHENOBARB) 60 mg OD-TDS

Primidone (MYSOLINE) 250-500 mg BD

II. Hydantoins

Diphenylhydantoin (Phenytoin; EPTOIN) 100-200 mg BD

Mephenytoin (MESANTOIN) 50-200 mg TDS

III. Iminostilbene derivatives

Carbamazepine (TEGRETAL) 200-400 mg. TDS

Oxcarbazepine (OXYTEL) 600-1200 mg BD

IV. Succinimides

Ethosuximide (ZARONTIN) 250-500 mg TDS

Methsuximide 300 mg OD-TDS

V. Oxazolidinediones

Trimethadione (TROXIDONE) 300-600 mg TDS

VI. Aliphatic carboxylic acid

Valproic acid (Sodium valproate; EPIVAL) 200-800 mg TDS

VII. Benzodiazepines

Clonazepam (EPITRIL) 0.5-4 mg TDS

Diazepam (CALMPOSE) 0.2-0.5 mg/kg IV

Clobazam (CLODUS) 20-60 mg OD-BD

VIII.Phenyltriazine derivative

Lamotrigine (LAMEPIL) 300-500 mg BD

IX. Newer compounds

Felbamate 2-4 g/day

Topiramate (TOPEX) 200-400 mg BD

Tiagabine 16-56 mg/day