Page 264 - ILAE_Lectures_2015

Chapter 26

Starting antiepileptic drug treatment

KHALID HAMANDI

Welsh Epilepsy Centre, University Hospital of Wales, Cardiff
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The single most important consideration before starting antiepileptic medication is to be
secure of the diagnosis of epilepsy based on the clinical history and, where needed,
supporting investigations. Antiepileptic drug (AED) treatment should never be started as a
trial to ‘test’ the diagnosis; this will only cause problems for you and the patient, and is
generally unhelpful in resolving diagnostic uncertainty.

Given a likely clinical diagnosis the next questions are when to start treatment, followed by
what choice of AED. AEDs should prescribed after a careful evaluation of the risks and
benefits of treatment and a discussion with the individual patient about the merits and
potential side effects of treatment1. The decision to start medication is a major one – treatment
will be for many years, even lifelong, and future withdrawal will bring its own issues around
recurrence risk and driving, for instance. The decision to start will depend upon factors such
as the risk of recurrence, seizure type, the risk around implication of further seizures, desire
to regain a driving licence and, for women, the risks of AEDs and seizures in pregnancy.

Antiepileptic medication is normally taken for years, and good adherence is essential to avoid
withdrawal seizures. Before starting any medication it is important to give information about
side effects, drug interactions, teratogenicity and driving. It is helpful to have to hand one or
two of the commonest possible side effects for each AED, to caution the patient about these
for any new drug started and to document this clearly in notes and letters. Individuals need
to appreciate that starting medication does not hasten the return of their driving licence, and
that the DVLA recommend not driving during withdrawal and for six months after stopping
AEDs. Patients choosing not to start medication need to be warned of the risks of seizures
including, if appropriate, SUDEP (sudden unexplained death in epilepsy).

When to start antiepileptic medication – the single seizure

When dealing with a single generalised tonic-clonic seizure (GTCS) it is important to make
sure that the patient has just had a single seizure by asking carefully about events or
symptoms that the patient would not necessarily recognise as seizures or volunteer in the
history, e.g. myoclonic jerks, stereotyped focal symptoms with retained awareness,
symptoms like epigastric rising, déjà vu, periods with loss of awareness, and seizure-markers
from sleep.

In 2014 the ILAE task force presented a new category for epilepsy diagnosis, and in addition
to the established ‘at least two unprovoked seizures occurring more than 24 hours apart’ was
added ‘one unprovoked seizure and a probability of further seizures similar to the general
recurrence risk after two unprovoked seizures (at least 60%)’2. Examples are a single seizure
occurring one month after a stroke, or a single seizure with a structural abnormality, for
instance focal cortical dysplasia on MRI. While the ILAE task force publication does not
concern itself with when to start AEDs, this new definition does have implications for the
treating clinician and should be discussed with the patient and documented. It is left to the
treating clinician to apply the >60% risk of recurrence in these situations; this is very difficult
to estimate in clinic, and most clinicians would currently agree that starting AEDs after a
single seizure is not appropriate in the majority of circumstances.