Topiramate belongs to a group of medications that are used to treat epilepsy. It works by affecting chemicals in the brain that are involved in sending signals to nerves.

Topiramate is used to treat epilepsy and to prevent migraine headaches.

For epilepsy, topiramate can be used alone or in combination with other epilepsy medications. For migraine prevention, topiramate is used to treat adults who have 4 or more migraine headaches a month and who have not responded to, or cannot take, medications that treat an acute migraine attack.

This medication may be available under multiple brand names and/or in several different forms. Any specific brand name of this medication may not be available in all of the forms or approved for all of the conditions discussed here. As well, some forms of this medication may not be used for all of the conditions discussed here.

Your doctor may have suggested this medication for conditions other than those listed in these drug information articles. If you have not discussed this with your doctor or are not sure why you are taking this medication, speak to your doctor. Do not stop taking this medication without consulting your doctor.

Do not give this medication to anyone else, even if they have the same symptoms as you do. It can be harmful for people to take this medication if their doctor has not prescribed it.

When used alone for the treatment of epilepsy, the recommended starting dose of topiramate for adults and children 6 years of age and older is 25 mg daily, increasing to a usual dose of 100 mg daily in 2 divided doses. The maximum recommended dose is 400 mg daily.

When used in combination with other epilepsy medications, the recommended adult dose of topiramate starts at 25 mg to 50 mg daily, increasing to a usual dose of 200 mg to 400 mg daily in 2 divided doses. The maximum recommended dose is 800 mg daily. The recommended dose for children aged 2 to 16 years starts at 25 mg daily (or 1 mg to 3 mg per kilogram of body weight), increasing to a usual dose of 5 mg to 9 mg per kilogram per day in 2 divided doses.

For migraine prevention, the usual starting dose of topiramate is 25 mg daily, increasing to a usual dose of 100 mg daily in 2 divided doses.

The tablets can be taken with or without food. Topiramate tablets should not be broken, crushed, or chewed. The sprinkle capsules can be swallowed whole or opened and sprinkled on a small amount (teaspoon) of soft food. The medication and food should be swallowed immediately and not chewed.

If it becomes necessary to stop taking topiramate, the dose should be gradually reduced to prevent a return of seizures or migraines. Talk to your doctor before stopping the medication.

Many things can affect the dose of medication that a person needs, such as body weight, other medical conditions, and other medications. If your doctor has recommended a dose different from the ones listed here, do not change the way that you are taking the medication without consulting your doctor.

It is important to take this medication exactly as prescribed by your doctor. If you miss a dose, take it as soon as possible and continue with your regular schedule. If it is almost time for your next dose, skip the missed dose and continue with your regular dosing schedule. Do not take a double dose to make up for a missed one. If you are not sure what to do after missing a dose, contact your doctor or pharmacist for advice.

Store this medication at room temperature in its original package, protect it from light and moisture, and keep it out of the reach of children.

Do not take this medication if you:

• are allergic to topiramate or any ingredients of the medication

If you are taking this medication to prevent migraines, do not take this medication if you:

• are pregnant
• may become pregnant and are not using effective birth control.

Do not give this medication to children under 2 years of age.

Many medications can cause side effects. A side effect is an unwanted response to a medication when it is taken in normal doses. Side effects can be mild or severe, temporary or permanent.

The side effects listed below are not experienced by everyone who takes this medication. If you are concerned about side effects, discuss the risks and benefits of this medication with your doctor.

The following side effects have been reported by at least 1% of people taking this medication. Many of these side effects can be managed, and some may go away on their own over time.

Contact your doctor if you experience these side effects and they are severe or bothersome. Your pharmacist may be able to advise you on managing side effects.

• altered taste
• decreased appetite
• dizziness
• drowsiness
• fatigue
• headache
• nausea

Although most of the side effects listed below don't happen very often, they could lead to serious problems if you do not seek medical attention.

Check with your doctor as soon as possible if any of the following side effects occur:

• aggressive behaviour
• agitation
• burning or tingling sensations
• confusion
• coordination problems
• difficulty concentrating or slow thinking
• memory problems, forgetfulness
• mood swings
• nervousness
• signs of depression (e.g., poor concentration, changes in weight, changes in sleep, decreased interest in activities, thoughts of suicide)
• signs of high blood ammonia (e.g., decreased alertness, tiredness, vomiting)
• signs of kidney stones (e.g., flank pain, blood in urine, pain in lower back)
• signs of metabolic acidosis (e.g., unexplained tiredness, loss of appetite, decreased consciousness)
• slowed speech
• slowed thinking
• speech disorders (e.g., hesitancy or word-finding difficulty)
• unexplained tiredness, vomiting, or confusion
• more frequent upper respiratory tract infections (e.g., colds, bronchitis)
• weight loss

Stop taking the medication and seek immediate medical attention if any of the following occur:

• decreased sweating and increased body temperature
• signs of a serious allergic reaction (e.g., abdominal cramps, difficulty breathing, nausea and vomiting, or swelling of the face and throat)
• signs of severe skin reactions (e.g., blistering, peeling, a rash covering a large area of the body, a rash that spreads quickly, or a rash combined with fever or discomfort)
• sudden vision change (e.g., blurred vision, painful red eyes, vision loss)
• thoughts of self-harm or suicide

Some people may experience side effects other than those listed. Check with your doctor if you notice any symptom that worries you while you are taking this medication.

Before you begin using a medication, be sure to inform your doctor of any medical conditions or allergies you may have, any medications you are taking, whether you are pregnant or breast-feeding, and any other significant facts about your health. These factors may affect how you should use this medication.

Ammonia: Topiramate may cause elevated levels of ammonia in the blood, which can cause changes in mental alertness. If you have symptoms of decreased alertness, confusion, tiredness, vomiting, or a low body temperature (less than 35°C), contact your doctor immediately.

Birth control: Topiramate has been shown to affect birth control pills that contain low doses of estrogen. If you are taking birth control pills, your pill should contain no less than 30 µg of estrogen. Report any changes in bleeding patterns to your doctor.

Depression: Topiramate may contribute to mood swings and symptoms of depression. If you have depression or a history of depression, discuss with your doctor how this medication may affect your medical condition, how your medical condition may affect the dosing and effectiveness of this medication, and whether any special monitoring is needed. If you experience symptoms of depression such as poor concentration, changes in weight, changes in sleep, decreased interest in activities, or notice them in a family member who is taking this medication, contact your doctor as soon as possible.

Drowsiness/reduced alertness: Topiramate can cause difficulty with concentration, speech or language problems, and drowsiness or fatigue. If you are taking this medication, you should not drive or operate machinery until you have had a chance to see if it affects your mental or physical performance.

Heat regulation: For some people, especially children, topiramate may cause decreased sweating and increased body temperature. Let your doctor know if you or a child taking this medication experiences these symptoms. You should make sure you are properly hydrating during exposure to warm temperatures, as well as before and during exercise.

Kidney function: Kidney disease or reduced kidney function may cause this medication to build up in the body, causing side effects. If you have reduced kidney function or kidney disease, discuss with your doctor how this medication may affect your medical condition, how your medical condition may affect the dosing and effectiveness of this medication, and whether any special monitoring is needed.

Kidney stones: Approximately 2% of people taking topiramate develop kidney stones. Men seem to be at greater risk for this. Be sure to drink plenty of fluids while taking this medication in order to reduce the risk of kidney stone formation. If you experience pain in the kidney or flank areas, contact your doctor to have this investigated.

Liver function: Liver disease or reduced liver function may cause this medication to build up in the body, causing side effects. If you have liver problems, discuss with your doctor how this medication may affect your medical condition, how your medical condition may affect the dosing and effectiveness of this medication, and whether any special monitoring is needed. Your doctor may want to test your liver function regularly with blood tests while you are taking this medication.

Metabolic acidosis: Topiramate may cause high levels of acid in the blood resulting in a condition called metabolic acidosis. This can lead to brittle or soft bones. If you or your child have symptoms such as shallow, rapid breathing, unusual tiredness, loss of appetite, confused thinking or decreased consciousness, contact your doctor immediately.

Nervous system effects: As with other medications that treat seizures, topiramate may cause difficulty with concentration or speech and language. It can also cause unsteadiness, memory problems, or tingling and numbness. If you experience these symptoms, talk to your doctor.

Suicidal or agitated behaviour: People taking this medication may feel agitated (restless, anxious, aggressive, emotional, and feeling not like themselves), or they may want to hurt themselves or others. These symptoms may occur within several weeks after starting this medication. If you experience these side effects or notice them in a family member who is taking this medication, contact your doctor immediately. You should be closely monitored by your doctor for emotional and behaviour changes while taking this medication.

Stopping treatment: When topiramate is stopped suddenly, it can cause seizures or an increase in seizure frequency. This medication should be stopped gradually to decrease the risk of seizures. If it is necessary to stop taking topiramate, discuss with your doctor the best way to reduce your dose gradually. Do not stop taking this medication without talking to your doctor.

Vision changes: This medication may cause the symptoms of glaucoma (increased pressure in the eye) to become worse. This can happen to children as well as adults taking topiramate. If you have glaucoma, discuss with your doctor how this medication may affect your medical condition, how your medical condition may affect the dosing and effectiveness of this medication, and whether any special monitoring is needed. If you are taking topiramate, you should immediately report blurred vision or painful and red eyes to a doctor. If left untreated, these symptoms can lead to permanent vision loss.

Pregnancy: Topiramate may cause harm to the developing baby if it is taken during pregnancy. This medication should not be used during pregnancy unless the benefits outweigh the risks. If you become pregnant while taking this medication, contact your doctor immediately.

Breast-feeding: This medication may pass into breast milk. If you are breast-feeding and taking topiramate, it may affect your baby. Talk to your doctor about whether you should continue breast-feeding.

Children and adolescents: Topiramate can be used for children aged 2 years and older for seizures. The safety and effectiveness of using this medication have not been established for children under the age of 2 years. The safety and effectiveness of using this medication to prevent migraine headaches has not been established for children less than 18 years of age.

For a full list of interactions, use the Drug Interaction Checker available on the Drugs.com website.

If you are taking other medications, speak with your doctor or pharmacist. Depending on your specific circumstances, your doctor may want you to:

• stop taking one of the medications,
• change one of the medications to another,
• change how you are taking one or both of the medications, or
• leave everything as is.

An interaction between two medications does not always mean that you must stop taking one of them. Speak to your doctor about how any drug interactions are being managed or should be managed.

Tell your doctor or prescriber about all prescription, over-the-counter (non-prescription), and herbal medications you are taking. Also tell them about any supplements you take. Since caffeine, alcohol, the nicotine from cigarettes, or street drugs can affect the action of many medications, you should let your prescriber know if you use them.