Precautions and Warnings With Zonisamide
There are several precautions and warnings with zonisamide people should be aware of before taking it. For example, the drug should not be taken by those who are allergic to sulfonamides ("sulfa" drugs). In addition, zonisamide has the potential to cause a life-threatening skin rash. Precautions and warnings with zonisamide also extend to people with kidney or liver disease or blood disorders.
- A history of kidney stones
- Any blood disorder
- Liver disease, including liver failure, hepatitis, or cirrhosis
- Kidney disease, including kidney failure (renal failure)
- Any allergies, including allergies to food, dyes, or preservatives.
Also, let your healthcare provider know if you are:
- Pregnant or thinking of becoming pregnant
Make sure to tell your healthcare provider about all the medicines you take, including prescription and non-prescription medicines, vitamins, and herbal supplements.
Warnings and precautions to be aware of prior to taking zonisamide include the following:
- Zonisamide is a sulfonamide ("sulfa" drug). If you are allergic to sulfonamides, you should not take zonisamide.
- The medication can cause life-threatening skin rashes, which may cause a loss of large sections of skin (resulting in disfigurement or even death). Let your healthcare provider know immediately if you have an unexplained rash while taking the drug. Your healthcare provider will decide if your rash might become dangerous and may recommend stopping zonisamide.
- Zonisamide can affect the bone marrow's ability to make blood cells. Let your healthcare provider know if you have signs of low blood cells, including easy bruising or bleeding or frequent infections.
- Zonisamide has been reported to cause cases of decreased sweating accompanied by a fever. This can be dangerous and can lead to heat stroke and even death. Children are at an increased risk for this problem. Let your healthcare provider know if you notice decreased sweating, especially in warm weather.
- As with all seizure medications, zonisamide should not be stopped suddenly (see Zonegran Withdrawal).
- Zonisamide can cause concentration problems, speech problems, drowsiness, and problems with coordination. Be sure to tell your healthcare provider if you develop any of these side effects while taking the drug. Also, make sure that you know how zonisamide affects you before driving or operating any machinery.
- The medication can increase your risk of kidney stones. One way to help prevent this is to drink plenty of water to stay hydrated. Zonisamide may not be the best medication for you if you are prone to kidney stones.
- Zonisamide can cause metabolic acidosis, a condition in which there is too much acid in the body. Among other things, metabolic acidosis increases the risk of kidney stones. Kidney disease, severe respiratory disorders, diarrhea, a "ketogenic" diet (a high-fat, low-carbohydrate diet often used by people with epilepsy), or certain other medications may increase the risk of metabolic acidosis with zonisamide. Be sure to watch for any symptoms of this problem, such as:
- Fast breathing
- Fatigue or tiredness
- An irregular heart rhythm (arrhythmia)
- Feelings of a rapidly or forcefully beating heart (palpitations).
- Zonisamide can slightly decrease your kidney function. For most people, this is not a problem. However, if you already have kidney problems, any decrease in kidney function can be dangerous.
- It is possible that zonisamide may increase the risk of status epilepticus (a dangerous seizure that lasts a very long time, often more than 30 minutes). If you have a seizure that lasts longer than usual (or is different in any way from your usual seizures), seek immediate medical attention.
- About 1 percent of people taking zonisamide report experiencing extreme weakness. This usually goes away once the medication is stopped.
- In dogs, zonisamide binds to tissues in the eye, suggesting that it may cause eye problems. It is not known if this is also true for humans. Tell your healthcare provider if you notice any eye or vision problems that are possibly due to zonisamide.
- The liver helps remove zonisamide from your body. If you have liver disease, your healthcare provider may suggest a lower zonisamide dosage.
- Zonisamide can interact with other medications (see Drug Interactions With Zonisamide).
- Zonisamide is considered a pregnancy Category C medication. This means that it may not be safe for pregnant women. Talk to your healthcare provider about the risks and benefits of taking the drug while pregnant (see Zonegran and Pregnancy).
- Zonisamide passes through breast milk. Therefore, if you are breastfeeding or plan to start, discuss this with your healthcare provider prior to taking the drug (see Zonegran and Breastfeeding).
Early evidence suggests that seizure medications, including zonisamide, may increase the risk of suicidal thoughts or behaviors (see Seizure Medications and Suicide for more information).