Clinical Pharmacology and Therapeutics

134 ANTI-EPILEPTICS
Is it true epilepsy?
Yes
No
No
Is it secondary to an
underlying CNS or
generalized abnormality?
No
Are these reversible or
precipitating factors?
Yes
Yes
Consider underlying
disorder
– brain tumour
– brain abscess
– stroke
– alcohol withdrawal
– other
Investigate for other
disorder
– Syncope
– dysrhythmia
– pseudo-epilepsy
– metabolic disturbance
(e.g. hypoglycaemia)
– drug withdrawal
– other
Are seizures frequent
and/or likely to present
risk to patients?
Yes
No
Address these:
– flashing lights
– stress
– alcohol/alcohol withdrawal
– drugs
Drug treatment No drug treatment
(see Table 22.1)
Figure 22.1: Pathway for the management of epilepsy.
• Are there remediable or reversible factors that aggravate
the epilepsy or precipitate individual attacks?
• Is there a clinically important risk if the patient is left
untreated?
• What type of epilepsy is present?
The ideal anti-epileptic drug would completely suppress
all clinical evidence of epilepsy, while producing no immediate
or delayed side effects. This ideal does not exist (the British
National Formulary currently lists 23 anti-epileptic drugs),
and the choice of drug depends on the balance between efficacy
and toxicity and the type of epilepsy being treated. Table
22.1 summarizes the most common forms of seizure and their
drug treatment.
Control should initially be attempted using a single drug
which is chosen on the basis of the type of epilepsy. The dose is
increased until either the seizures cease or the blood drug concentration
(see Chapter 8) is in the toxic range and/or signs of
toxicity appear. It should be emphasized that some patients
have epilepsy which is controlled at drug blood concentrations
below the usual therapeutic range, and others do not manifest
toxicity above the therapeutic range. Thus, estimation of drug
plasma concentration is to be regarded as a guide, but not an
Table 22.1: Choice of drug in various forms of seizure
Form of seizure First line Second line
Partial seizures with Valproate Phenytoin
or without secondary Carbamazepine Topiramate
generalized tonic–clonic Lamotrigine Tiagabine
seizures
Generalized seizures
Primary (tonic–clonic) Valproate Clonazepam/
Lamotrigine
clobazam
Topiramate
Phenytoin
Absence seizures Ethosuximide Lamotrigine
Valproate
Clobazam/
clonazepam
Myoclonic jerks Valproate Lamotrigine
Clonazepam
Other anti-epileptics not listed above may be useful. Refer to National
Institute for Clinical Excellence (NICE) guidelines.