Levetiracetam And Its Effects On Transcranial Motor Evoked Potentials During Surgery

Levetiracetam (AKA Keppra)

It’s pretty widely accepted that inhalational agents and muscle relaxants will reduce the effectiveness of transcranial motor evoked potentials during surgery. There is also a growing amount of evidence that Precedex should also be considered a medication on the “only use if necessary, and then really limit the amount if you have to use it, but we probably should use it” list.

But there are some less often used medications that can cause effects on motor evoked potentials that we need to be aware of. For example, I already wrote about the effects of sugammadex on muscle relaxants when you have 0/4 twitches. Not something you’re likely to see tomorrow, but who knows what tomorrow brings. If the anesthesiologist happened to ask you if it is OK to use this with what you’re recording, you need to be able to give an informed answer.

Like inhalational agents and Dexmedetomidine, another medication that has some evidence to decreasing motor evoked potentials during surgery is Levetiracetam (also known as Keppra). This drug is used for anticonvulsant purposes and is typically given perioperatively. If you’re doing craniotomies, then you’re used to hearing the anesthesiologist tell the surgeon that Keppra was given.

At the 2014 Winter Society for Pediatric Anesthesia (SPA) meeting held in conjunction with the American Academy of Pediatrics (AAP) Section on Anesthesiology and Pain Medicine, Hsu et al presented a case report demonstrating the loss and recovery of motor evoked potentials during the use of Levetiracetam infusion during a craniotomy.

In that presentation, they highlight an abrupt change once the Levetiracetam infusion began with recovery to baselines as the infusion was aborted. This was reported twice during the case during times where it was not thought reasonable to be a cause due to surgery or other metabolic factors.

As pointed out by the author, this shouldn’t be too much of a stretch to believe seeing as Keppra is thought to inhibit presynaptic calcium channels which can lower the amount of neurotransmitter released and has been shown to decrease magnetic motor evoked potentials when given orally.

In my own little neuromonitoring world, it seems like there is an increase in surgical orders to utilize neuromonitoring for craniotomies. Knowing about the transient effects of Levetiracetam can help the surgical team better understand when to give the medication and how to utilize motor evoked potentials during that time.