This page covers the single and add-on anti-seizure medication options for treating tonic or atonic seizures.
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Specialist referral
People with a diagnosis of tonic or atonic seizures should be referred for assessment by a neurologist with expertise in epilepsy to:
- Diagnose the syndrome, if possible, and
- Advise on investigation and treatment
First single anti-seizure medication options
Sodium valproate (Epilim and other brand names) is the first single anti-seizure medication treatment for myoclonic seizures in:
- Boys and men
- Girls under 10 who are unlikely to need treatment when they’re old enough to have children
- Women who can’t have children
However, there are new rules that apply to valproate treatments (see more information below). The treatment recommendations from NICE (the National Institute for Health and Care Excellence) that relate to valproate are currently being reviewed.
Women and girls who can have children, including young girls likely to need treatment when they’re old enough to have children, will be offered lamotrigine (Lamictal and other brand names) as a first treatment.
Second and third single anti-seizure medication and add-on options
If sodium valproate doesn’t work, lamotrigine can be tried as a second single anti-seizure medication or as an add-on treatment.
If lamotrigine doesn’t work, one of the following can be tried as a single anti-seizure medication or add-on treatment:
- Clobazam (Frisium, Onfi and other brand names)
- Rufinamide
- Topiramate (Topamax and other brand names)
If the first choice doesn’t work, the others can be tried.
Sodium valproate (Epilim and other brand names) should not be used for tonic or atonic seizures in women and girls who can have children, including young girls who likely to need treatment when they’re old enough to have children, unless:
- Other treatments don’t work
- The benefits and risks have been fully discussed, including the risks to an unborn child
- The likelihood of pregnancy has been taken into account and a pregnancy prevention programme is in place, if appropriate
There are new rules that apply to valproate treatments (see more information below). The treatment recommendations from NICE (the National Institute for Health and Care Excellence) that relate to valproate are currently being reviewed.
Sodium valproate
In January 2024, new rules were introduced for prescribing sodium valproate.
Two specialists are now needed to approve:
- New or ongoing valproate treatments for girls and women.
- New valproate treatments for boys and men
The specialists must agree that your epilepsy does not respond to other treatments and the benefits of treatment outweigh the risks.
For girls and women, valproate can seriously harm an unborn baby when taken during pregnancy.
For boys and men, valproate may cause infertility. Some people’s fertility may return when their treatment is stopped or reduced. There is also some evidence that valproate can cause harm in the testicles of animals, but it’s unclear what this means for humans.
Never stop taking valproate before talking to your specialist first. Not taking medication as prescribed can increase the risk of a seizure.
Your epilepsy specialist will let you know when your treatment is due to be reviewed.
If you are planning a pregnancy it is important to speak to your healthcare professional as soon as possible about your treatment options.
If you have any questions or concerns about valproate, please speak to your healthcare professional.
Find out more about sodium valproate in the MHRA’s patient guide.
Find out more about Anti-seizure medications, contraception and pregnancy.
Further treatment options
If none of the third options work for tonic or atonic seizures in children, ketogenic diet can be tried as an add-on treatment, under the supervision of a ketogenic diet team.
If all other treatment options for tonic or atonic seizures are unsuccessful, felbamate (MedPointe) can be tried as an add-on treatment, under the supervision of a neurologist with expertise in epilepsy.
Switching from the first to second and third single anti-seizure medication
During the switch from the first single anti-seizure medication to the second option:
- The dose of the first anti-seizure medication remains the same while the dose of the second is increased slowly
- If the second anti-seizure medication works, the dose of the first will be slowly tapered off
- If the second anti-seizure medication doesn’t work, the dose will be slowly tapered off and a third option considered
Switching to using add-on anti-seizure medications
When starting an add-on treatment, the dose will be managed carefully and reviewed frequently.
This will include monitoring for side effects such as feeling sedated.
If add-on treatments don’t reduce seizures, epilepsy specialists will aim for the combination of anti-seizure medications that is the most effective while and has tolerable side effects.
Epilepsy specialists will discuss with the person, and their family or carers, as appropriate, the benefits of taking as few medicines as possible for seizure freedom or control.
Anti-seizure medications that may make seizures worse
The following anti-seizure medications may make tonic or atonic seizures worse:
- Carbamazepine (Tegretol and other brand names)
- Gabapentin (Neurontin and other brand names)
- Oxcarbazepine (Trileptal and other brand names)
- Pregabalin (Lyrica and other brand names)
- Tiagabine (Gabitril)
- Vigabatrin (Sabril)
