Zonisamide
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DRUG STATUS
Government Approvals
US(FDA), UK(BNF)
WHO Essential Medicine
NO
Known Teratogen
Definite
Pharmaceutical Class
Anti-epileptic Agent
Zonisamide
Learn more about this medicine -
Click HereSummary
Zonisamide is used to help control seizures in adults with epilepsy. It's not a cure, but it works alongside other epilepsy medications to reduce the number of seizures.
Zonisamide calms overactive brain cells by affecting certain channels in these cells, making them less excitable. After taking it by mouth, it reaches its highest level in the blood within a few hours and stays in the body for a long time.
Zonisamide is taken by mouth. It comes in capsules (50mg and 100mg) and a liquid (100mg in 5 milliliters). You start with 100mg a day, and the dose might increase every two weeks up to 400mg based on your doctor's advice.
Zonisamide can cause side effects like drowsiness, dizziness, mood changes, and difficulty thinking clearly. In rare cases, it can cause more serious mental health problems like psychosis or worsen existing depression. It can also lead to weight loss due to reduced appetite.
Zonisamide carries risks of permanent vision loss, severe skin reactions, and decreased sweating leading to overheating. It may cause metabolic acidosis and hyperammonemia, which can be life-threatening. Users should be alert for changes in mood, including suicidal thoughts. Stopping the medication suddenly can trigger seizures.
Indications and Purpose
What is Zonisamide used for?
Zonisamide capsules are a medicine to help control seizures in adults with epilepsy. They're not a cure, but they work alongside other epilepsy medications to reduce the number of seizures. This medicine is only for adults over 16. It's not safe or approved for use in younger people.
How does Zonisamide work?
Zonisamide is a medicine that calms overactive brain cells. It does this by affecting certain channels in these cells, making them less excitable. It also affects an enzyme in the body, but whether that helps it work better isn't completely clear. After taking it by mouth, the medicine reaches its highest level in the blood within a few hours. It stays in the body for a long time, much longer in red blood cells than in the rest of the blood. Most of it leaves the body through urine.
Is Zonisamide effective?
Zonisamide helps some adults with partial seizures. Studies show it works well for many people at doses between 100 and 600 milligrams a day. Going above 400 milligrams usually doesn't help much more. However, there haven't been specific studies to perfectly figure out the best dose. It's important to note that this medicine isn't for children under 16.
How does one know if Zonisamide is working?
The benefits of Zonisamide are evaluated through clinical trials that measure its effectiveness in treating conditions like epilepsy and obesity. Researchers assess factors such as seizure frequency and weight changes, often comparing Zonisamide to a placebo. Statistical analysis ensures that observed benefits are significant. Additionally, systematic reviews combine results from multiple studies to confirm Zonisamide's overall efficacy and safety in various patient populations.
Directions for Use
What is the usual dose of Zonisamide?
For adults, the initial recommended dose of Zonisamide is 100 mg daily. The dose can be increased by 100 mg every two weeks based on clinical response and tolerability, up to a maximum of 600 mg daily. However, evidence suggests no increased response above 400 mg/day. Zonisamide is not approved for use in children under 16 years of age.
How do I take Zonisamide?
You can take Zonisamide with or without food, so choose what works best for you. It's important to drink plenty of water while on this medication to help prevent kidney stones. There are no specific food restrictions, but staying hydrated is key. Always follow your doctor's instructions regarding dosage and timing. If you have any questions or concerns, don’t hesitate to reach out to your healthcare provider.
For how long do I take Zonisamide?
The typical duration of Zonisamide use varies based on the condition being treated. For epilepsy, it is often used for a minimum of eight weeks to assess effectiveness. In studies, the average treatment duration can range from about 186 days to over 780 days, depending on individual patient needs and responses. Continuous monitoring and adjustments may be necessary throughout the treatment period to ensure optimal results. Always follow your healthcare provider's guidance regarding duration.
How long does it take for Zonisamide to start working?
It takes about two weeks for your body to get used to a new medicine dose. You'll start with 100mg a day. After two weeks, the dose might go up to 200mg. If needed, it could go up again to 300mg and then 400mg, with another two weeks in between each increase to let your body adjust.
How should I store Zonisamide?
Keep the medicine Zonisamide at room temperature, not too hot or too cold. Keep it away from light. Throw away any leftover medicine one month after you open the bottle. Make sure kids can't get to it.
Warnings and Precautions
Who should avoid taking Zonisamide?
Important warnings for Zonisamide include the risk of permanent vision loss, severe skin reactions, and decreased sweating leading to overheating. Users should be alert for changes in mood, including suicidal thoughts. Additionally, Zonisamide may cause metabolic acidosis and hyperammonemia, which can be life-threatening. It's crucial to report any eye pain, rash, or unusual symptoms to a healthcare provider immediately. Avoid stopping the medication suddenly without medical advice, as this can trigger seizures.
Can I take Zonisamide with other prescription drugs?
Zonisamide can cause problems if taken with other similar medicines (carbonic anhydrase inhibitors) because they can make your body too acidic, raise ammonia levels, and increase the risk of kidney stones. It can also affect how your body handles some other drugs like digoxin and quinidine, so your doctor needs to be aware if you're taking these. However, it generally doesn't interact strongly with many other common seizure medications or birth control pills. Certain medications that speed up your liver's activity (CYP3A4 inducers) might make zonisamide less effective, but others that slow it down don't seem to have much impact.
Can I take Zonisamide with vitamins or supplements?
Zonisamide may interact with certain vitamins and supplements, particularly vitamin D, which can be affected by long-term use of anticonvulsants like Zonisamide. This interaction may lead to lower vitamin D levels and potential bone health issues. It's advised to monitor vitamin D intake and consider supplementation if necessary. Additionally, while no significant interactions with vitamin B12 or other vitamins were found, it's always best to consult a healthcare provider before adding any supplements to your routine while using Zonisamide.
Can Zonisamide be taken safely while pregnant?
Zonisamide is a medicine that needs careful thought if you're pregnant. There's no evidence it causes specific problems like acidosis or death in babies, but those things can happen anyway for other reasons. It's best to use birth control while taking this medicine and for a month after stopping it. If you're pregnant and taking zonisamide, you should join a pregnancy registry to help doctors learn more.
Can Zonisamide be taken safely while breastfeeding?
If a mother takes the medicine zonisamide while breastfeeding, her baby needs close watching. The medicine passes into breast milk, so the baby might show signs like poor feeding, weight loss, sleepiness, weak muscles, or a high temperature. However, serious problems from this are rare. Doctors need to balance the good things about breastfeeding with the mother's need for the medicine and any small risks to the baby. Talk to your doctor about what's best for you and your baby.
Is Zonisamide safe for the elderly?
Start older adults on the lowest dose of Zonisamide. While a single dose acts similarly in older and younger people, there aren't enough studies on older adults to know for sure how the drug will affect them differently, especially since they often have liver, kidney, or heart problems, or take other medications.
Is it safe to exercise while taking Zonisamide?
Zonisamide may affect your ability to exercise, especially strenuously. It can cause side effects like dizziness, drowsiness, or coordination problems, which might make physical activity harder or less safe. It also increases the risk of dehydration and overheating, as it can reduce sweating. This means you should be extra careful during strenuous exercise or in hot weather. Stay hydrated, take breaks, and listen to your body. If you feel dizzy, lightheaded, or overheated while exercising, stop immediately and cool down.
Is it safe to drink alcohol while taking Zonisamide?
Drinking alcohol occasionally or moderately while taking Zonisamide can increase side effects like drowsiness, dizziness, or difficulty concentrating. Alcohol may also worsen the medicine’s effects on your thinking and coordination, making it less safe to do activities like driving or exercising. While alcohol doesn’t directly interfere with how Zonisamide works, combining the two can make side effects more noticeable.
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