Epilepsy – Drug safety and side effects
General points

Prescribe by brand
Loss of seizure control may occur when patients are switched between different manufacturers
preparations of the same anticonvulsant due to differences in bioavailabililty
It is recommended that Anti Epileptic Drugs) AEDs are prescribed by brand name and that patients
are not transferred to a different brand or preparation without clinical support

Suicidal thoughts / behaviour
Guidance from the MHRA states that AED treatment may be associated with a small risk of suicidal
ideation. Data suggests that this can occur with all available drugs and is seen from as early as a
week after initiating treatment.
Doctors should warn of this and ask the patient to be aware of any mood changes etc and seek
medical help if necessary.

Interactions / herbal medicine use
Many AEDs will interact with other common medications.
Enzyme inducers eg. Phenytoin may necessitate a higher dose of other medications eg steroids (may
need to be doubled)
Oral contraceptives may be ineffective
St John’s wort is listed as interacting with MOST AEDs

Administration in advanced disease
If oral route unavailable some preparations available IV or in acute instance IM/PR benzodiazepines
may be administered. In palliative medicine it is common to substitute anti-epeleptics for
midazolam/clonazepam delivered via CSCI
AED side effects
First line agents
Generic name
Carbamazepine
Ethosuximide
Lamotrigine
Levetiracetam
Oxcarbazepine
Sodium Valproate
Common side effects
Dry mouth, nausea, vomiting, fluid retention,
unsteadiness, dizziness, drowsiness, fatigue,
headache, hyponatreaemia, dermatitis
Nausea, vomiting, diarrhoea, abdominal pain,
anorexia, and weight loss.
Nausea, vomiting, diarrhoea, dry mouth,
aggression, agitation, headache, drowsiness,
dizziness, tremor, difficulty sleeping,
unsteadiness, back pain, joint pain, eye
movements, double vision, and blurred vision.
Anorexia, weight changes, abdominal pain,
nausea, vomiting, diarrhoea, drowsiness,
unsteadiness, dizziness, headache, tremor,
amnesia, aggression, agitation, depression,
anxiety, and double or blurred vision.
Skin rash, nausea, vomiting, constipation,
diarrhoea, abdominal pain, dizziness, headache,
drowsiness, agitation, amnesia, hair loss,
weakness, unsteadiness, confusion, depression,
and tremor.
Hair loss - not usually severe and is usually
reversible if the dose is reduced.
Nausea, abdominal pain, diarrhoea, and weight
gain (due to increased appetite), increased levels
of ammonia in the blood, and reduced platelets.
Has been associated with polycystic ovaries and
menstrual problems.
Sodium valproate carries a higher risk than other
AEDs of causing developmental problems in
unborn babies if taken during pregnancy. Having
preconceptual counselling is recommended.
Second line agents
Acetazolamide
Clobazam
Clonazepam
Gabapentin
Lacosamide
Phenobarbital
Phenytoin
Piracetam
Pregabalin
Topiramate
Nausea, vomiting, diarrhoea, taste disturbance,
loss of appetite, pins and needles, flushing,
headache, dizziness, fatigue, irritability,
excitement, unsteadiness, depression, thirst,
increased urination, and reduced libido.
Drowsiness, lightheadedness, confusion,
unsteadiness, amnesia, dependence, aggression,
and muscle weakness.
Drowsiness, fatigue, dizziness, low muscle tone,
coordination problems, low concentration,
restlessness, confusion, amnesia, and
dependence.
Diarrhoea, nausea, vomiting, dry mouth,
appetite changes, weight gain, hypertension,
fluid retention, confusion, depression, sleep
disturbance, headache, dizziness, anxiety,
tremor, unsteadiness, flu-like symptoms,
incontinence, impotence, and double vision.
Nausea, vomiting, constipation, wind, dizziness,
headache, impaired co-ordination, drowsiness,
tremor, depression, fatigue, abnormal walking,
blurred vision, eye movements, and itching.
Hepatitis, hypotension, drowsiness, lethargy,
depression, unsteadiness, and impaired memory
or cognition.
Nausea, vomiting, constipation, nystagmus,
drowsiness, insomnia, nervousness, tremor, pins
and needles, dizziness,ataxia, slurred speech,
duptyren’s contracture, headache, anorexia,
gum problems, acne, excess hair growth, and
coarsening of facial features.
Weight gain, nervousness, and overactive
restlessness.
Dry mouth, constipation, vomiting, wind, fluid
retention, dizziness, irritability, low attention,
muscle and movement problems, speech
disorder, impaired memory, pins and needles,
euphoria, confusion, insomnia, blurred or double
vision, and sexual dysfunction.
Nausea, diarrhoea, vomiting, constipation,
indigestion, abdominal
pain, dry mouth, appetite changes, impaired
attention, cognition and coordination,
movement problems, tremor, drowsiness,
dizziness, anxiety, confusion, mood changes,
depression, irritability, and anaemia.