C H A P T E R 2 3
Antiseizure agents
357
TABLE 23.2
DRUGS IN FOCUS Drugs for treating generalised seizures
Drug name
Dosage/route
Usual indications
Hydantoins
phenytoin (Dilantin)
Adult: 100 mg PO t.d.s., up to 300–400 mg/
day; 10–15 mg/kg IV
Paediatric: 5–8 mg/kg per day PO; 5–10 mg/kg
IV in divided doses
Treatment of tonic–clonic seizures,
prevention of status epilepticus and
treatment of seizures after neurosurgery
Barbiturates and barbiturate-like drugs
phenobarbitone
(generic)
Adult: 60–100 mg/day PO; 200–320 mg IM
or IV for acute episodes, may be repeated in
6 hours; reduce dose with elderly and with
renal or hepatic impairment
Paediatric: 3–6 mg/kg per day PO; 4–6 mg/
kg per day IM or IV; 15–20 mg/kg IV over
10–15 mins for status epilepticus
Long-term treatment of tonic–clonic
seizures localised in the cortex; treatment
of cortical focal seizures, simple partial
seizures, febrile seizures; used as a
sedative/hypnotic; emergency control
of status epilepticus and acute seizures
associated with eclampsia, tetanus and
other conditions
primidone (Mysoline)
Adult: 250 mg PO five to six times per day
Paediatric (>8 years): 250 mg PO five to six
times per day
Paediatric (<8 years): 125–250 mg PO t.d.s.
Alternative choice in treatment of tonic–
clonic, partial, febrile and refractory
seizures; may be combined with other
agents to treat seizures that cannot be
controlled by any other antiseizure agents
Benzodiazepines
clonazepam (Rivotril)
Adult: initially 1.5 mg/day PO in three divided
doses, up to a maximum 20 mg/day
Paediatric (<2 years): 0.5–1 mg/day
Paediatric (2–5 years): 1.5–3 mg/day
Paediatric (6–12 years): 3–6 mg/day
Treatment of absence and myoclonic
seizures; administered to people who
do not respond to succinimides; being
studied for use in the treatment of panic
attacks, restless leg movements during
sleep, hyperkinetic dysarthria, acute
manic episodes, multifocal tic disorders,
neuralgias and as an adjunct in the
treatment of schizophrenia
diazepam (Valium)
Adult: 2–10 mg PO b.d. to q.i.d.; 0.2 mg/kg PR,
may repeat in 4–12 hours; 2–20 mg IM or IV
Geriatric or debilitated people: 2–2.5 mg PO
daily to b.d.; or 2–5 mg IM or IV
Paediatric: 1–2.5 mg PO t.d.s. to q.i.d.; or
0.3–0.5 mg/kg PR with a repeat in 4–12 hours
if needed; 0.25 mg/kg IV over 3 mins, may
repeat in 15–30 mins for up to three doses
Treatment of severe convulsions, clonic–
tonic seizures, status epilepticus;
treatment of alcohol withdrawal and
tetanus; relieves tension, preoperative
anxiety; being studied for use in
treatment of panic attacks; this drug is no
longer used for long-term management
of epilepsy
Succinimides
ethosuximide
(Zarontin)
Adult and paediatric: 20–30 mg/day in two
divided doses
Drug of choice for treatment of absence
seizures
Drugs that modulate the inhibitory neurotransmitter gamma-aminobutyric acid
acetazolamide (Diamox)
250–1000 mg/day PO regardless of age;
250 mg PO daily if used with other
antiepileptics
Treatment of absence seizures, especially
in children with open-angle and
secondary glaucoma; to decrease
oedema associated with heart failure and
drug use; and as a prophylaxis and for
mountain sickness
sodium valproate (Epilim)
Initially, 600 mg/day. Maximum 2.5 g/day
Paediatric: use extreme caution, determine
dose by age and weight
Drug of choice for myoclonic seizures;
second-choice drug for treatment of
absence seizures; also effective in mania,
migraine headaches and complex partial
seizures
vigabatrin (Sabril)
Initially, 1000–3000 mg/day PO
Treatment of epilepsy not well controlled
by other antiepileptic drugs
zonisamide (Zonegran)
Adults (>16 years): 100 mg PO daily up to
600 mg/day
Adjunct for treatment of absence seizures
