Which of the following drugs is least efficacious in the treatment of temporal lobe epilepsy?
(A) Phenobarbitone (B) Phenytoin sodium (C) Primidone (D) Carbamazepine
(C) Complex partial seizures (CPS, temporal lobe epilepsy, psychomotor): attacks of bizarre and confused behaviour dream-like state and purposeless movements, or even walking, unaware emotional changes lasting 1-2 min along with impairment of consciousness. The patient has no recollection of the attack. An aura often precedes. The seizure focus is located in the temporal lobe.​
Phenobarbitone was the first efficacious anti-epileptic introduced in 1912.​
Primidone A deoxybarbiturate, which is converted by liver to phenobarbitone and phenylethyl malonamide (PEMA). Its antiepileptic activity is mainly due to these active metabolites because t1/2 of primidone (6-14 hr) is less than that of its active metabolites. About 1/3 primidone is excreted unchanged by kidney. Dose to dose primidone is less potent, but antiepileptic efficacy is similar to phenobarbitone. It is seldom used now in GTGC and partial epilepsy, mainly as an adjuvant to phenytoin or carbamazepine.
Adverse effects are similar to phenobarbitone. In addition, anemia, leukopenia, psychotic reaction and lymph node enlargement occur rarely.
Dose: Start with 250 mg OD, then 250-500 mg BD, children 10-20 mg/kg/day.
MYSOLINE 250 mg tab.
Reference: Essentials of Medical Pharmacology Eighth Edition KD TRIPATHI page no 438,443​