Topiramate is a medication that 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.

Topiramate works by affecting chemicals in the brain that are involved in sending signals to nerves.

Your doctor may have suggested this medication for conditions other than the ones 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 in adults and children 6 years of age and older is 25 mg daily, increasing to a usual dose of 100 mg daily in two 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 two divided doses. The maximum recommended dose is 800 mg daily. Recommended doses for children aged 2 to 16 years start 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/kg/day in two 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 two divided doses.

The tablets can be taken with or without food. Topiramate tablets should not be broken. 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.

Topamax® is supplied as 25 mg, 100 mg, and 200 mg tablets and as 15 mg and 25 mg Sprinkle Capsules.

25 mg tablets: Each white, round, coated tablet, marked "TOP" on one side and "25" on the other, contains 25 mg of topiramate.

100 mg tablets: Each yellow, round, coated tablet, marked "TOP" on one side and "100" on the other, contains 100 mg of topiramate.

200 mg tablets: Each salmon, round, coated tablet, marked "TOP" on one side and "200" on the other, contains 200 mg of topiramate.

Nonmedicinal ingredients for tablets: carnauba wax, hydroxypropyl methylcellulose, lactose monohydrate, magnesium stearate, pregelatinized starch, microcrystalline cellulose, polyethylene glycol, polysorbate 80, purified water, sodium starch glycolate, titanium dioxide, and may contain synthetic iron oxide.

15 mg Sprinkle Capsule: Each clear, white, gelatin capsule marked with "TOP" and "15 mg" on the side, contains 15 mg of topiramate as small white-to-off-white spheres.

25 mg Sprinkle Capsule: Each clear, white, gelatin capsule marked with "TOP" and "25 mg" on the side, contains 25 mg of topiramate as small white-to-off-white spheres.

Nonmedicinal ingredients for Sprinkle Capsules: black pharmaceutical ink, cellulose acetate, gelatin, povidone, silicon dioxide, sodium lauryl sulphate, sugar spheres (sucrose and starch), and titanium dioxide.

Anyone with an allergy to topiramate or any ingredients of the tablet or Sprinkle Capsules should not take this medication.

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 health professional.

The following side effects may go away as your body becomes used to the medication; check with your doctor if they continue or become bothersome.

More common
• diarrhea
• drowsiness
• headache
• nausea

Less common or rare
• back pain
• chest pain
• constipation
• heartburn
• increased sweating
• tremor

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

More common
• burning or tingling sensations
• difficulty concentrating
• dizziness
• memory problems
• physical or mental slowing
• unusual tiredness

Less common or rare
• agitation
• aggressive behaviour
• confusion
• decreased appetite
• depressed mood
• difficulty breathing
• difficulty sleeping
• eye pain
• flushing
• nervousness
• red eyes
• skin rash
• swelling
• vision changes
• weight loss

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.

Be sure to inform your physician of all your medical conditions before you begin taking a medication. Some conditions can affect how you should take this medication.

Drowsiness/reduced alertness: Topiramate can cause difficulty with concentration, speech or language problems, and drowsiness or fatigue. People taking this medication should not drive or operate machinery until they have had a chance to see if it affects their 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. Proper hydration during exposure to warm temperatures, as well as before and during exercise, is recommended.

Kidney stones: Approximately 1.5% 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.

Laboratory tests: Topiramate may decrease sodium bicarbonate levels and lead to metabolic acidosis. Sodium bicarbonate levels should be monitored for people receiving topiramate.

Liver function: Topiramate should be used with caution by people with decreased liver function.

Stopping treatment: Topiramate should be stopped gradually to decrease the risk of seizures. Do not stop taking this medication without talking to your doctor.

Vision changes: People taking topiramate should immediately report blurred vision or painful and red eyes to a doctor. If left untreated, these symptoms can lead to permanent vision loss.

Birth control: Topiramate has been shown to affect birth control pills that contain low doses of estrogen. Women taking birth control pills should receive a preparation containing not less than 30 µg of estrogen and report any changes in bleeding patterns.

Pregnancy: There are no studies on the use of topiramate by pregnant women. It should not be used during pregnancy unless the potential benefit outweighs the risk.

Breast-feeding: Limited information shows that topiramate is found in breast milk. Since there is the potential for serious adverse reactions in nursing infants, a decision should be made whether to stop nursing or stop the medication. In making this decision, the benefit of the medication to the mother and the risks to the infant should be considered.

Children and adolescents: Topiramate can be used in children aged 2 and older. Safety and effectiveness in children under the age of 2 has not been established.

The following medications can affect the way topiramate works:

• carbamazepine
• phenytoin

The following can be affected by topiramate:

• acetazolamide
• amitriptyline
• digoxin
• CNS depressants (medications that slow down the central nervous system, such as alcohol, sedatives, or morphine)
• hydrochlorothiazide
• metformin
• oral contraceptives (birth control pills)
• phenytoin
• pioglitazone
• risperidone

If you are taking any of these 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. In many cases, interactions are intended or are managed by close monitoring. Speak to your doctor about how any drug interactions are being managed or should be managed.

Medications other than those listed above may interact with this medication. Tell your doctor or prescriber about all prescription, over-the-counter (non-prescription), and herbal medications that 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.