Most people with a seizure disorder can have anesthesia safely, and the anesthetic plan is usually adjusted to lower the chance of a seizure. General anesthetic medicines often raise the seizure threshold, which means seizures are less likely during surgery. The medicines that are usually best tolerated include propofol, benzodiazepines such as midazolam, and isoflurane. Sevoflurane has been linked to seizure-like activity in some children, and nitrous oxide is generally avoided in people with epilepsy.

Before surgery, the team looks closely at the seizure history and the usual medicine plan. They review how often seizures happen, when the last one was, what they look like, and whether there has ever been status epilepticus, which means a seizure that lasts too long or keeps going. They also check for missed doses, recent changes in medicine, and other drugs that may affect liver enzyme activity and change how seizure medicines or anesthetic drugs work. If a person has known seizure triggers, the team tries to reduce them, such as poor sleep, changes in food or water intake, withdrawal from caffeine, drugs, or alcohol, bright flashing lights, and missed antiseizure medicine doses.

Antiseizure medicines are usually continued through the perioperative period whenever possible. If a single dose is missed, it should be given back as soon as possible after surgery. Whether surgery goes ahead after a missed dose depends on the type and urgency of the surgery, how often breakthrough seizures happen, and the overall risk discussion around surgery and anesthesia.

During surgery, some people need more anesthetic medicine because certain antiseizure drugs speed up drug breakdown in the liver. The anesthesia team may need to redose medicines more often. EEG, which is brain-wave monitoring, is the most accurate way to spot a seizure during anesthesia, especially if the patient is paralyzed. BIS monitoring can also help, although it is less exact. If a seizure happens, it is usually treated with propofol, midazolam, and sometimes levetiracetam, and an extra dose of the home antiseizure medicine may be given if an IV form is available.

The highest risk time for a breakthrough seizure is after surgery. The team watches closely for delayed wake-up, unusual confusion, airway trouble, or breathing problems. If a seizure occurs after surgery, treatment can include IV benzodiazepines, oxygen, review of missed home doses, and sometimes a preventive medicine such as levetiracetam or phenytoin. If a vagus nerve stimulator is present, it is usually turned off before elective surgery, and magnets may be used in an emergency to disable some implanted stimulators.