• Keep this leaflet. You may need to read it again.
• If you have any further questions, ask your doctor or your pharmacist.
• This medicine has been prescribed for you only. Do not pass it on to others. It may harm them, even if their signs of illness are the same as yours.
• If you get any side effects talk to your doctor or pharmacist. This includes any possible side effects not listed in this leaflet. See section 4.

1. What Zonisamide is and what it is used for
2. What you need to know before you take Zonisamide
3. How to take Zonisamide
4. Possible side effects
5. How to store Zonisamide
6. Contents of the pack and other information

• On its own to treat seizures in adults.
• With other antiepileptic medicines to treat seizures in adults, adolescents, and children aged 6 years and above.

• if you are allergic to zonisamide or any of the other ingredients of this medicine (listed in section 6).
• if you are allergic to other sulphonamide medicines. Examples include: sulphonamide antibiotics, thiazide diuretics, and sulfonylurea antidiabetes medicines.

Zonisamide belongs to a group of medicines (sulphonamides) which can cause severe allergic reactions, severe skin rashes, and blood disorders, which very rarely can be fatal (see section 4. Possible Side Effects).

Serious rashes occur in association with Zonisamide therapy, including cases of Stevens-Johnson syndrome.

Talk to your doctor or pharmacist before taking Zonisamide if you:

• are younger than 12 years old, as you may be at greater risk of decreased sweating, heat stroke, pneumonia and liver problems. If you are younger than 6 years old, Zonisamide is not recommended for you.
• are elderly, as your dose of Zonisamide may need adjusting, and you may be more likely to develop an allergic reaction, severe skin rash, swelling of the feet and legs, and itchiness when taking Zonisamide (see section 4. Possible Side Effects).
• suffer from liver problems, as your dose of Zonisamide may need adjusting.
• have eye problems such as glaucoma.
• suffer from kidney problems as your dose of Zonisamide may need adjusting.
• have previously suffered from kidney stones, as you may be at increased risk of developing more kidney stones. Reduce the risk of kidney stones by drinking sufficient water.
• live in a place or are on holiday in a place where the weather is warm. Zonisamide can make you perspire less, which can cause your body temperature to increase. Reduce the risk of overheating by drinking sufficient water and keeping cool.
• are underweight, or have lost a lot of weight as Zonisamide can cause you to lose more weight. Tell your doctor as this may need to be monitored.
• are pregnant or could become pregnant (see section ‘pregnancy, breast-feeding and fertility’ for further information).

If any of these applies to you, tell your doctor before you take Zonisamide.

The use of Zonisamide may lead to high levels of ammonia in the blood which could lead to a change in brain function, especially if you are also taking other medicines which can increase ammonia levels (for example valproate), have a genetic disorder causing build-up of too much ammonia in the body (urea cycle disorder), or if you have liver problems. Tell your doctor immediately if you become unusually drowsy or confused.

Talk to your doctor about the following risks:

Preventing overheating and dehydration in children

Zonisamide can cause your child to sweat less and overheat and if your child is not treated this can lead to brain damage and death. Children are most at risk especially in hot weather.

When your child is taking Zonisamide:

• Keep your child cool especially in hot weather
• Your child must avoid heavy exercise especially when the weather is hot
• Give your child plenty of cold water to drink
• Your child must not take these medicines:
  carbonic anhydrase inhibitors (like topiramate and acetazolamide), and anticholinergic agents (like clomipramine, hydroxyzine, diphenhydramine, haloperidol, imipramine and oxybutynin)

If your child’s skin feels very hot with little or no sweating, becomes confused, has muscle cramps, or your child’s heartbeat or breathing becomes rapid:

• Take your child to a cool, shaded place
• Sponge your child’s skin with cool (not cold) water
• Give your child cold water to drink
• Seek urgent medical assistance
• Body weight: You should monitor your child’s weight every month and see your doctor as soon as possible if your child is not gaining enough weight. Zonisamide is not recommended for children who are underweight or have a small appetite, and should be used with caution in those below 20kg.
• Increased acid level in the blood and kidney stones: Reduce these risks by ensuring that your child drinks enough water and is not taking any other medicine which could cause kidney stones (see: Other medicines).
  Your doctor will monitor your child’s blood bicarbonate levels and kidneys (see also section 4).

Do not give this medicine to children below the age of 6 years because it is not known for this age group whether the potential benefits are greater than the risks.

Please tell your doctor or pharmacist if you are taking, or have recently taken, any other medicines, including medicines obtained without a prescription.

• Zonisamide should be used carefully in adults when taken with medicines that can cause kidney stones, like topiramate or acetazolamide. In children, this combination is not recommended.
• Zonisamide could possibly increase your blood levels of medicines like digoxin and quinidine, and so a reduction in their dose may be required.
• Other medicines like phenytoin, carbamazepine, phenobarbitone and rifampicin can decrease your blood levels of Zonisamide, which may require an adjustment of your dose of Zonisamide.

Zonisamide can be taken with or without food.

• If you are or think you may be pregnant, you must tell your doctor straight away and discuss possible risks the epilepsy medicine you are taking might pose to your unborn baby.
• If you are planning to become pregnant you should discuss your epilepsy treatment with your doctor as early as possible before you stop contraception and before you become pregnant, about the possibility of switching to other suitable treatments. If you are or think you might be pregnant, tell your doctor straight away.
• You should not stop your treatment without discussing this with your doctor. Suddenly stopping may lead to breakthrough seizures which may harm you and your unborn baby. It is important that your epilepsy remains well controlled.

Pregnancy

You must only take Zonisamide during your pregnancy if your doctor tells you to. If you are a woman of childbearing age you must use adequate contraception while taking Zonisamide and for one month after stopping Zonisamide.

Studies have shown an increased risk of physical birth abnormalities in children of women taking epilepsy medicines during pregnancy. The risk of physical birth abnormalities may increase when more than one epilepsy medicine is used at the same time. Where possible, your doctor should consider using one epilepsy medicine to control your epilepsy.

More research is needed to better understand whether taking Zonisamide during pregnancy increases the risk of having a baby born with a physical birth abnormality or a learning or thinking disability. The risk of birth defects or neurodevelopmental disorders (problems with brain development) for your child after taking Zonisamide during your pregnancy is unknown.

Studies have shown that babies born to mothers using Zonisamide during pregnancy were smaller than expected for their age at birth, compared with babies born to mothers treated with lamotrigine monotherapy.

Zonisamide may affect your concentration, ability to react/respond, and may make you feel sleepy, particularly at the beginning of your treatment or after your dose is increased. Be especially careful while driving or operating machinery, if Zonisamide affects you in this way.

When you take Zonisamide on its own:

• The starting dose is 100mg taken once a day.
• This may be increased by up to 100mg at intervals of two weeks.
• The usual dose is 300mg once a day.

When you take Zonisamide with other antiepileptic medicines:

• The starting dose is 50mg daily taken in two equal doses of 25mg.
• This may be increased by up to 100mg at intervals of one to two weeks.
• The recommended daily dose is between 300mg and 500mg.
• Some people respond to lower doses. The dose may be increased more slowly if you experience side effects, are elderly or if you suffer from kidney or liver problems.

Use in children (aged 6 to 11 years) and adolescents (aged 12 to 17 years) weighing at least 20kg:

• The starting dose is 1mg per kg of body weight taken once a day.
• This may be increased by 1mg per kg of body weight at intervals of one to two weeks.
• The recommended daily dose is 6 to 8mg per kg for a child with a body weight of up to 55kg or 300 to 500mg for a child with a body weight more than 55kg (whichever dose is lower) taken once a day.

Example: A child who weighs 25kg should take 25mg once a day for the first week, and then increase the daily dose by 25mg at the start of each week until a daily dose between 150 to 200mg is reached.

If you feel that the effect of Zonisamide is too strong or too weak, talk to your doctor or pharmacist.

• Zonisamide capsules must be swallowed whole with water.
• Do not chew the capsules.
• Zonisamide can be taken once or twice daily, as instructed by your doctor.
• If you take Zonisamide twice a day, take half the daily dose in the morning and half in the evening.

If you may have taken more Zonisamide than you should, tell a carer (relative or friend), your doctor or pharmacist immediately, or contact your nearest hospital casualty department, taking your medicine with you.

You may become sleepy and could lose consciousness. You might also feel sick, have a sore stomach, muscle twitches, eye movement, feel faint, have a slowed heartbeat, and reduced breathing and kidney function. Do not try to drive.

• If you forget to take a dose, don’t worry: take the next dose when it is due.
• Do not take double the dose to make up for the forgotten dose.

• Zonisamide is meant to be taken as a long-term medicine. Do not reduce your dose or stop your medicine unless your doctor tells you to.
• If your doctor advises you to stop taking Zonisamide your dose will be reduced gradually to lower the risk of more seizures.

• have difficulty breathing, a swollen face, lips or tongue, or a severe skin rash as these symptoms may indicate that you are having a severe allergic reaction.
• have signs of overheating - high body temperature but little or no sweating, rapid heartbeat and breathing, muscle cramps, and confusion.
• have thoughts of harming or killing yourself. A small number of people being treated with anti-epileptics such as Zonisamide have had thoughts of harming or killing themselves.
• have pain in your muscles or a feeling of weakness, as this may be a sign of abnormal muscle breakdown which can lead to kidney problems.
• get a sudden pain in your back or stomach, have pain on urinating (passing water) or notice blood in your urine, as this may be a sign of kidney stones.
• develop visual problems such as eye pain or blurred vision while taking Zonisamide.

• have an unexplained skin rash, as this could develop into a more severe skin rash or skin peeling.
• feel unusually tired or feverish, have a sore throat, swollen glands, or find that you bruise more easily, as this may mean you have a blood disorder.
• have signs of increased acid level in the blood-headaches, drowsiness, shortness of breath and loss of appetite. Your doctor may need to monitor or treat this.

Your doctor may decide that you should stop using Zonisamide.

The most common side effects of Zonisamide are mild. They occur during the first month of treatment and usually decrease with continued treatment. In children ages 6 – 17 years old, side effects were consistent with those described below with the following exceptions: pneumonia, dehydration, sweating decreased (common) and abnormal liver enzymes (uncommon).

Very common side effects: may affect more than 1 in 10 people

• agitation, irritability, confusion, depression.
• poor muscle coordination, dizziness, poor memory, sleepiness, double vision.
• loss of appetite, decreased blood levels of bicarbonate (a substance that prevents your blood from becoming acidic).

Common side effects: may affect up to 1 in 10 people

• difficulty sleeping, strange or unusual thoughts, feeling anxious or emotional.
• slowed thoughts, loss of concentration, speech abnormalities, abnormal skin sensation (pins and needles), tremor, involuntary movement of the eyes.
• kidney stones.
• skin rashes, itching, allergic reactions, fever, tiredness, flu-like symptoms, hair loss.
• ecchymosis (a small bruise caused by blood leaking from broken blood vessels in the skin).
• loss of weight, nausea, indigestion, stomach pains, diarrhoea (loose stools), constipation.
• swelling of the feet and legs.

Uncommon side effects: may affect up to 1 in 100 people

• anger, aggression, thoughts of suicide, suicide attempt.
• vomiting.
• gall bladder inflammation, gallstones.
• urinary stones.
• lung infection / inflammation, urinary tract infections.
• low blood potassium levels, convulsions / seizures.

Very rare side effects: may affect up to 1 in 10,000 people

• hallucinations, memory loss, coma, neuroleptic malignant syndrome (inability to move, sweating, fever, incontinence), status epilepticus (prolonged or repeated seizures).
• breathing disorders, shortness of breath, inflammation of the lungs.
• inflammations of the pancreas (severe pain in the stomach or back).
• liver problems, kidney failure, increased blood levels of creatinine (a waste product that your kidneys should normally remove).
• severe rashes or skin peeling (at the same time you may feel unwell or develop a fever).
• abnormal muscle breakdown (you may feel pain or weakness in your muscles) which can lead to kidney problems.
• swollen glands, blood disorders (reduction in the number of blood cells, which can make infection more likely and can make you look pale, feel tired and feverish, and bruise more easily).
• decreased sweating, overheating.
• glaucoma, which is a blockage of fluid in the eye causing increased pressure in the eye. Eye pain, blurred vision or decreased vision may occur and can be signs of glaucoma.

If you get any side effects, talk to your doctor or pharmacist. This includes any possible side effects not listed in this leaflet. You can also report side effects directly via the Yellow Card Scheme at: www.mhra.gov.uk/yellowcard or search for MHRA Yellow Card in the Google Play or Apple App store. By reporting side effects you can help provide more information on the safety of this medicine.

Zonisamide 25mg hard capsules:

The active substance is zonisamide. Each capsule contains 25mg of zonisamide.

The other ingredients are:

• capsule contents: microcrystalline cellulose, hydrogenated vegetable oil and sodium laurilsulfate
• capsule shell: gelatin and titanium dioxide (E171)
• printing ink: shellac, black iron oxide (E172) and potassium hydroxide

Zonisamide 50mg hard capsules:

The active substance is zonisamide. Each capsule contains 50mg of zonisamide.

The other ingredients are:

• capsule contents: microcrystalline cellulose, hydrogenated vegetable oil and sodium laurilsulfate
• capsule shell: gelatin and titanium dioxide (E171)
• printing ink: shellac and iron oxide red (E172)

Zonisamide 100mg hard capsules:

The active substance is zonisamide. Each capsule contains 100mg of zonisamide.

The other ingredients are:

• capsule contents: microcrystalline cellulose, hydrogenated vegetable oil and sodium laurilsulfate
• capsule shell: gelatin and titanium dioxide (E171)
• printing ink: shellac, black iron oxide (E172) and potassium hydroxide

• Zonisamide 25mg hard capsules have a white opaque body and a white opaque cap, capsules size No. 4, 14.4mm, marked “Z 25” in black colour.
• Zonisamide 50mg hard capsules have a white opaque body and a white opaque cap, capsules size No. 3, 15.8mm, marked “Z 50” in red colour.
• Zonisamide 100mg hard capsules have a white opaque body and a white opaque cap, capsules size No 1, 19.3 mm, marked “Z 100” in black colour.

Zonisamide capsules are packaged in blister packs supplied in boxes containing:

• 25mg: 14, 28 and 56 capsules.
• 50mg: 14, 28 and 56 capsules.
• 100mg: 28, 56, 98 and 196 capsules.