epilepsy for pharmacists
What is epilepsy?
Epilepsy is the tendency to have recurrent seizures caused by a sudden burst of intense electrical activity in the brain. Epilepsy is the most common serious neurological condition in the UK, affecting more than 600,000 people*.
More people experience focal (also called partial) seizures than generalised seizures. Focal seizures start in a discrete area of the brain. Where in the brain this happens determines the nature of the seizures that occur. During focal seizures a person may be fully aware (simple focal seizures). Others, whilst not unconscious, are not aware of what is happening (complex focal seizures).
A focal seizure may spread to the whole brain leading to a bilateral convulsive seizure (sometimes called secondary generalised epilepsy).
In primary generalised seizures, both halves of the brain are involved from the start. These seizures are not preceded by an aura (simple focal seizure) so there is no warning that a seizure is starting.
Types of primary generalised seizures
- The muscles contract and the body goes stiff, the person may cry out, then lose consciousness and fall to the floor, cyanosed.
- They may bite their tongue.
- The clonic phase follows and muscles alternate between contraction and relaxation, resulting in jerky movements.
- They may be incontinent at this stage.
- After a few minutes they will go limp, then start to come round, often feeling groggy, with aching head and limbs.
- Some people may want to sleep after a seizure.
- The person goes stiff, if they are standing they often fall, usually backwards, causing possible head injuries.
- Seizures usually last less than 20 seconds.
Atonic seizures (drop attacks)
- The person goes limp and drops to the ground.
- They usually recover quickly, but head injury is a real possibility because they often fall forwards.
- These are similar to the sudden hypnic jerks that happen just as we are falling asleep, (but these jerks are not epileptic).
- Seizures may be brief, but do not affect awareness or consciousness.
- Seizures of this type often happen in clusters and are commonest in the morning.
- These seizures are more common in children than in adults.
- Child may appear to be daydreaming, look blank and stare, or their eyelids might flutter.
- Seizures are very brief, lasting only a few seconds.
- Child may be having hundreds of absence seizures a day meaning they miss key points in lessons and may find following instructions difficult, creating an impression of bad behaviour.
Complete seizure control is possible for the majority of patients with epilepsy by using anti-epileptic drugs (AEDs). For about 30% of people with epilepsy, AEDs do not control seizures satisfactorily.
Non-pharmacological treatment options may include the following.
- epilepsy surgery (neurosurgery);
- vagus nerve stimulation (VNS) therapy or deep brain stimulation therapy (DBS): implantable devices; and
- the ketogenic diet – a specialist diet that helps control seizures for some children with epilepsy. Dietary treatments are also being trialled in one or two clinics in the UK for adults.
Epilepsy and anti-epileptic drugs (AEDs)
NICE (opens in new window) states that ‘AED treatment strategy should be individualised according to the seizure type, epilepsy syndrome, co-medication and co-morbidity, the individual’s lifestyle, and the preferences of the individual and their family and/or carers as appropriate’.**
There are around 25 AEDs available.
- AEDs are not a ‘cure’ for epilepsy as they do not affect the underlying cause.
- AEDs are introduced gradually and increased until seizures are controlled or adverse effects are unacceptable.
- Ideally individuals should be treated with a single AED (monotherapy) wherever possible.
If initial treatment is unsuccessful, monotherapy using another drug may be tried. The changeover period needs to be monitored, so the replacement drug is built up to an adequate or maximum tolerated dose before the first drug is tapered off slowly. Polytherapy (using two or more AEDs) may be necessary for some individuals.
For more about indications for use, dosing and side effects see the British National Formulary (BNF) and BNF for Children (opens in new window).
Factors affecting adherence to AEDs
Epilepsy itself, the effect of seizures, and the effect of AEDs, can all affect memory for some people. Medication reminders may help in some cases. Switching to a twice-daily, slow-release formulation of an AED may be a possibility for some people.
Consistency of supply
Differences in bioavailability between products can be an issue for some AEDs and may result in an adverse drug reaction and/or changes in effectiveness. The MHRA (opens in new window) has issued guidance on when epilepsy medication should be prescribed by brand. Receiving different forms of their usual AEDs can confuse some patients or make them feel anxious about taking medication. This may affect seizure control and result in a lack of adherence. Ideally patients are given exactly the same formulation of AED with every prescription. Some people also prefer to avoid parallel imports for the same reason.
The use of generic AEDs in patients with epilepsy: a consensus view from the UK Clinical Pharmacists Association (UKCPA) neurosciences group and Pharmaceutical Market Support Group (PMSG) generics goup.
Routine blood monitoring is not usually required if the dose is stable, seizure control is good and the patient is side effect free. However monitoring is recommended:
- where toxicity is suspected;
- where pharmacokinetic interactions are suspected;
- where other conditions may affect drug levels, e.g. pregnancy or concomitant illness;
- where an adjustment to the dose of phenytoin is required; or
- to confirm potential non-adherence.
Points to cover with patients taking AEDs
AEDs are taken as an ongoing preventative treatment. They do not ‘cure’ epilepsy and are not a ‘course of treatment’. AEDs aim to stop seizures happening, so they need to be taken every day, continuously. AEDs are usually taken for a few years, and for many people, for life. If someone has been seizure-free for a few years, they might talk to their doctor about slowly withdrawing their medication.
It helps to take AEDs at about the same time each day. This helps to keep the level of drugs in the body constant, and to set a routine to remember to take them. Stopping or changing AEDs can result in seizures happening.
Side effects won’t necessarily happen, and don’t have to be ‘put up with’. Side effects can happen with all types of medicine, including AEDs, but this does not mean that everyone will get them. However, many people assume that they have to put up with side effects. If someone is having side effects that are intolerable, their prescribing doctor (usually their neurologist) may suggest changing to a different AED.
Any changes to AEDs are best done with the help of a healthcare professional. Discussing changes with a healthcare professional can be helpful, to manage seizures if they do happen.
Specific issues for women include links between hormones, puberty, contraception, pregnancy and the menopause. For example women (who are not planning a pregnancy) need to be using a contraceptive that does not interact with their AEDs. Enzyme inducing drugs reduce the effectiveness of the pill (in addition the AED lamotrigine can be affected by the pill). Women with epilepsy are also advised against using the progestogen implant. Contraceptive injections, such as Depo-Provera are recommended but usually repeated every 10 weeks instead of the normal 12. The IUD or IUS is effective for women taking AEDs. Women taking enzyme inducing AEDs need to have higher doses of emergency hormonal contraception.
Buccal midazolam can be given in status epilepticus,** a medical emergency where a person has prolonged or repeated seizures that last for 30 minutes or more without a complete recovery of consciousness. In the UK there are two products containing midazolam for buccal use, Buccolam® and Epistatus®. Buccolam has a license for children from 3 months up to the age of 18 and comes in pre-filled syringes. Epistatus has no license and is available as a multi-dose pack and pre-filled syringes.Other unlicensed named specials are available. Pharmacists should note that Buccolam and Epistatus contain different salts of midazolam and are available in different strengths. Buccolam is 10mg/2ml and Epistatus and specials are 10mg/1ml. Pharmacists need to ensure that the appropriate product is given.
When to refer a patient with epilepsy
There may be some specific issues that require a patient with epilepsy to be referred to a GP or specialist including:
- if seizures become worse or more frequent or if a patient is not under current review with a specialist;
- if there are any signs of adverse drug reactions; or
- if a patient is pregnant or planning a pregnancy.
Planning a pregnancy
All health care professionals should ensure that women planning a pregnancy have received preconception counselling.
Prognosis and complications
People who have uncontrolled seizures have an increased mortality rate. This relates to an increased risk of accidents, and sudden unexpected death in epilepsy (SUDEP).
About 800 – 1000 people die each year from epilepsy*.
People with uncontrolled epilepsy also have an increased risk of mental health problems, in particular depression. Epilepsy is also associated with significant social problems, including unemployment, problems with relationships, memory and social stigma.
Epilepsy Society provides support for people with epilepsy, their families, friends and carers (and provide resources for professionals).
Our confidential epilepsy helpline provides information and support. Epilepsy Society’s ‘epilepsy charter’ outlines the rights and services individuals with epilepsy can expect, including access to specialist services and appropriate treatment options.
Many areas of the country have GPs with Special Interest (GPwSI) in epilepsy – find out if you have someone in your locality undertaking this role. There may also be a local specialist epilepsy nurse, that you can contact, to get involved and learn more. There is potential in the future for pharmacists to become Pharmacists with Special Interest (PhwSI) in epilepsy too.
* Joint Epilepsy Council of the UK and Ireland (opens in new window). Epilepsy prevalence, incidence and other statistics. December 2011.