What is Zonisamide? Uses, warnings & side effects

Take this medicine as directed. The dose may need to be changed during the course of treatment.

Please read the Medication Guide that comes with the medicine.

Do not stop taking zonisamide until talking to the prescriber.

Zonisamide tablets or oral suspension can be taken with or without food.

Swallow the zonisamide capsule whole. Do not break, chew, or open it.

Shake the zonisamide oral suspension before measuring a dose.

Use a calibrated dosing device (such as a calibrated oral syringe) to measure doses of the oral suspension. Do not use kitchen measuring devices.

Store zonisamide capsules at room temperature protected from moisture and light.

Store zonisamide oral solution at room temperature protected from light. Dispose of the bottle and any remaining medicine 30 days after the bottle is opened.

Ask the prescriber what to do in case a dose of zonisamide is missed.

The doctor will probably advise that the missed dose be taken when remembered and that the next dose be taken at its regular time.

If it’s almost time for the next dose, the missed dose should be skipped, and the next dose should be taken when scheduled.

Some doctors may advise otherwise. Follow the directions of the prescriber.

This medicine is not right for everyone. 

Do not use it if you have had an allergic reaction to zonisamide or a sulfa drug.

Tell any physician or other healthcare provider who treats you that you are taking zonisamide.

The prescriber may require regular visits and blood tests to monitor the effects of treatment. Keep all appointments.  

Tell the prescriber if you are pregnant, breastfeeding, or have:

• Depression or other mental health concerns

• A history of suicidal thoughts or behaviors

• Kidney problems

• Liver problems

• A history of metabolic acidosis

• High levels of ammonia in the blood

• Bone problems

• A growth problem

Zonisamide could harm an unborn baby. Doctors will suggest that women taking zonisamide use appropriate birth control. Women who get pregnant should immediately inform the prescribing healthcare professional.

Zonisamide can cause serious health issues, including:

• Suicidal thoughts or behaviors

• Problems with thinking, concentrating, speaking, memory, or language

• Serious eye problems

• Metabolic acidosis (too much acid in the blood)

• Too much ammonia in the blood

• Anemia

• Low white blood cell counts

• Heat stroke (especially in children)

• Severe drug reactions 

This medicine may make you drowsy or dizzy. Do not drive or do anything else that could be dangerous until you know how zonisamide affects you.

Because this medicine reduces sweating, people taking zonisamide may easily overheat when exercising or exposed to hot weather. Use caution in hot weather. Don’t exercise too hard until you know how the medicine affects you.

This medicine reduces white blood cell levels, making people more vulnerable to infections. Take precautions to avoid infection. Wash your hands often. Avoid people who are sick.

Do not stop using this medicine suddenly. The sudden discontinuation of zonisamide may bring on more frequent or more severe seizures. Your doctor will need to slowly decrease the dose when it’s time to quit.

To avoid potentially hazardous drug interactions, tell the prescriber about all prescription drugs, over-the-counter medications, and supplements being taken, particularly:

• Drugs or supplements that cause sleepiness such as opioids, benzodiazepines, sleeping pills, CBD, or alcohol 

• Other carbonic anhydrase inhibitors such as acetazolamide

• Carbamazepine, cyclosporine, diazepam, dihydroergotamine, erythromycin, lidocaine, phenobarbital, phenytoin, primidone, terfenadine

Do not drink alcohol while taking zonisamide.

Avoid grapefruit and grapefruit juice when taking doses of zonisamide.

Tell your doctor if you are on a ketogenic diet (high-fat, low-carbohydrate diet).