Side Effect: Seizures

What are Seizures?

Seizures are a neurological condition (type of brain disorder) that happens when there is uncontrolled, abnormal electrical activity in the brain. There are many different types of seizures and symptoms can vary depending upon the area of the brain affected and the underlying cause of the seizure.

What do Seizures look like?

How a seizure manifests, or what it looks like, depends on the type of seizure, underlying cause, and the person experiencing it. Symptoms can range from mild to severe. It is important to note that not all seizures look the same or have the same symptoms. Symptoms of seizures may include:

• Muscle stiffness in the back, arms, legs
• Sudden loss of muscle control causing the person to fall
• Uncontrollable muscle contractions (convulsions)
• Staring into space or having a blank stare (staring spell)
• Rapid eye blinking
• Loss of consciousness
• Abnormal sensations or behavior
• Confusion
• Dizziness
• Sleepiness
• Loss of bowel or bladder control
• Breathing problems

For example, a person experiencing an absence (pronounced ab-sonce) seizure may not have any muscle jerking and may appear unresponsive to questioning.

People who experience a seizure may experience a postictal (pronounced post-ic-tal) state, which begins when the seizure ends and typically lasts between 5 – 30 minutes. People in the post-ictal state may experience disorienting symptoms such as drowsiness, headache, nausea, and confusion. Delirium from the postictal state usually lasts a few hours, but can persist for up to 2 days.

Who gets Seizures?

Brain tumors are a common cause of seizures in patients with cancer. In addition, other causes of seizures include:

• Trauma to the brain such as surgery or injury
• Radiation
• Infection
• Abnormal electrolytes
• Alcohol use disorder
• Substance use disorder
• Stroke
• Swelling of the brain
• High fevers
• Lack of sleep
• Some antidepressant medications
• A medication called desmopressin, or DDAVP, which may be used to prevent bleeding in certain patients

There are many types of cancer treatments that can increase the risk of developing seizures. Some of these treatments include:

• Brain radiation
• Busulfan
• Chimeric antigen receptor (CAR) T-cell therapy
• L-asparaginase
• Cisplatin
• 5-fluorouracil
• Ifosfamide
• Etoposide
• Methotrexate
• Blinatumumab
• Chlorambucil
• Enzalutamide

How to prevent Seizures

It is important to treat any underlying disorders that increase your risk of seizures such as abnormal electrolytes (especially sodium levels in the blood), high fevers, and lack of sleep. Some cancer treatments such as busulfan and CAR-T therapy may require anti-seizure medications during treatment to prevent seizures from occurring. In patients who have already had a seizure, anti-seizure medication may be prescribed to prevent a seizure from happening again.

Examples of anti-seizure medications include:

• Carbamazepine (Tegretol®)
• Clobazam (Onfi®)
• Lacosamide (Vimpat®)
• Lamotrigine (Lamictal®)
• Levetiracetam (Keppra®)
• Oxcarbazepine (Trileptal®)
• Phenobarbital (Sezaby®)
• Phenytoin (Dilantin®)
• Topiramate (Topamax®)
• Valproic acid (Depakote®)
• Zonisamide (Zonegran®)

Importantly, many antiseizure medications (except for Levetiracetam (Keppra®) interact with other medications. If you are taking an antiseizure medication it is important to make sure any new medications that are added to your regimen will not interact with it.

How to treat Seizures

The most common type of medication used to treat an ongoing seizure is a benzodiazepine. These medications can be given as a pill, placed under the tongue, between the cheek, or given rectally, intravenously, or nasally. Benzodiazepines are fast-acting and work quickly to get into the bloodstream. Examples of benzodiazepines include:

• Diazepam (Valium®)
• Lorazepam (Ativan®)
• Midazolam (Versed®)

Some anti-seizure medications can be used to both prevent and treat seizures if they occur. There are many different types of anti-seizure medications. These medications have different side effects, dosing instructions and can interact with other medications. It is important to talk with your doctor about which anti-seizure medication is right for you.