Epilepsy for pharmacists

• 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, or cheek. 
• 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 then want to sleep.

• There is a prolonged loss of consciousness.
• The person goes stiff and may fall backwards.
• The person may sustain significant injuries due to falling.

• There is a prolonged loss of consciousness.
• The person goes limp from the start and may flop forward if seated.
• The person may sustain significant injuries as a result of falling.

• The loss of consciousness is brief.
• People have sudden short-lasting jerks which can affect some or all of the body.
• Seizures of this type often happen in clusters and are most common in the morning. 

• The person briefly loses muscle tone and may lose their balance and fall, or struggle to regain their balance. 
• They may lose their grip on objects and drop them. 
• Negative myoclonic seizures can sometimes be a symptom of an epilepsy syndrome.

NICE states that the specialist should ‘develop an individualised anti-seizure medication treatment strategy with the person, and their family and carers if appropriate, taking into account: 

• sex;
• age;
•  seizure type;
• epilepsy syndrome;
•  whether treatment is needed;
•  risks and benefits of anti-seizure medications, including their importance in reducing the risk of epilepsy-related death
• possible interactions with any other medicines taken;
• any co-morbidities;
• the preferences of the person, and their family or carers if appropriate;
• personal circumstances, such as education, employment, likelihood of pregnancy, planning a family, driving, alcohol use and travel; and
• how and when anti-seizure medicines need to be taken.’
   

There are around 30 ASMs available. ASM is not a ‘cure’ for epilepsy as it does not affect the underlying cause. ASM is introduced gradually and increased until seizures are controlled or adverse effects are unacceptable. Ideally individuals should be treated with a single  ASM (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 ASMs) may be necessary for some individuals.

For more about indications for use, dosing, and side effects visit the British National Formulary and British National Formulary for Children – bnf.nice.org.uk.

Because epilepsy is caused by a problem in the brain, other cognitive issues, especially memory problems, commonly occur. The effect of seizures and, in some cases, the effects of ASM, can also interfere with memory. Medication reminders, alarms, or other compliance aids may help some people. 

Differences in bioavailability between products can be an issue for some ASM and may result in an adverse drug reaction and/or changes in effectiveness. The Medicines and Healthcare products Regulatory Agency (MHRA) has issued guidance on when epilepsy medication should be prescribed by brand. 

Receiving different forms of their usual ASM 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 ASM with every prescription. Some people also prefer to avoid parallel imports for the same reason.

In January 2024 the MHRA introduced new restrictions on the prescribing of valproate. Valproate is also known as sodium valproate, valproate semisodium, or valproic acid. Brand names include Epilim, Depakote, Convulex, Episenta, Epival, Kentlim, Orlept, Sodium Valproate, Syonell, Valpal, Belvo and Dyzantil.

• Men and women under the age of 55 should not be started on valproate without two specialists independently determining the need for valproate is appropriate.
• No-one should stop taking their ASM without consulting their doctor.

Girls and women under 55 of child bearing potential and already taking valproate will need sign off from two specialists to continue as part of their annual review for a year following the introduction of these changes. After this they will continue to have an annual review with one specialist. 

The current regulatory measures also mean that no woman or girl of childbearing potential should be prescribed valproate, unless there is no other effective treatment available, in which case there should be a pregnancy prevention programme in place. 

The MHRA states that ‘In women who take valproate while pregnant, around 1 in 9 babies (11%) will have a birth defect’ and ‘about 3 or 4 children in every 10 may have problems with early childhood development’.

The MHRA has also introduced some recommendations for men taking valproate who might potentially father a child. These include: 

• Men should discuss plans for pregnancy with their epilepsy specialist;
• Men under 55 should use condoms;
• Their female partner should use effective contraception; and
• They should not donate sperm.

New safety measures have also been introduced for the epilepsy medication, topiramate, also known by the brand name Topamax. These measures follow a major safety review triggered by a European study which showed that children born to mothers who take topiramate during pregnancy face a two to three times higher risk of intellectual disabilities, autism spectrum disorders, and attention deficit hyperactivity disorder (ADHD). The MHRA states that:

• Topiramate should no longer be prescribed for epilepsy during pregnancy unless there is no suitable alternative treatment.
• Any woman or girl of childbearing potential newly started on topiramate would be required to take a pregnancy test before it is started to rule out pregnancy.
• Those already taking the medication will need to be using highly effective birth control during treatment. 
• Healthcare professionals should discuss the risks associated with the medication with patients and ensure that a risk awareness form is signed.

Some contraceptive methods are less effective than others when using topiramate due to its enzyme inducing potential. A patient’s GP or sexual healthcare practitioner will be able to help advise which form of birth control is right for them. 

Regular medication reviews, at least once annually, with a specialist are also recommended for patients taking it for epilepsy.

The introduction of the Pregnancy Prevention Programme will further strengthen these safety measures and aim to reduce the number of topiramate-exposed pregnancies.

Anyone thinking of starting a family who currently takes valproate or females on topiramate for epilepsy, should not stop taking the medication but should seek the advice of a specialist. Stopping medication without supervision may cause their seizures to start again, happen more often, or last longer. 

Safety and educational materials have been introduced for patients and healthcare professionals to support these measures. 

Dispensing pharmacists should also provide a patient card for all females prescribed topiramate, and males and females prescribed valproate, and provide advice.

Both valproate and topiramate should be dispensed in its original packaging ideally or, if this isn’t possible, add a copy of the package leaflet. 

Suspected adverse drug reactions associated with either of these ASMs, should continue to be reported to the Yellow Card scheme.

It is recommended that topiramate is treated as an enzyme inducer which can restrict the choices of highly effective contraception for women taking it.

In addition, the ASM lamotrigine can be affected by the oestrogen in the combined hormonal contraceptive pill and other contraceptives containing oestrogen, leading to possible lowering of lamotrigine levels and loss of seizure control. 

It is also possible that lamotrigine may affect the efficacy of progestogen containing pills.

Contraceptive injections, such as Depo-Provera are recommended for women with epilepsy as they have good efficacy (if replaced regularly) and do not interact with ASM. 

Women of child bearing potential taking valproate or topiramate are advised to use a ‘highly effective’ method of contraception which is defined as a method that is user independent. For this group of patients, Depo-Provera is only considered ‘highly effective’ if the woman has the injection without fail every 12 weeks. 

Intrauterine devices (IUDs) or Intrauterine systems (IUSs) are effective for women taking ASM, including enzyme-inducers, and are considered ‘highly effective’ for women taking valproate or topiramate.

Women taking enzyme-inducing ASM need to have higher doses of emergency hormonal contraception. Only levonorgestrel is recommended for this group.

For women planning a pregnancy, preconceptual care from a specialist is essential. Most ASM has teratogenic potential, but strengthened guidance has been issued on sodium valproate and, more recently, on Topiramate (see above). 

All health care professionals should ensure that women planning a pregnancy have received preconception counselling.

Also, Women taking ASM and planning a pregnancy should be taking folic acid 5mg daily. This is usually continued until week 12 of pregnancy.