Topiramate

What is topiramate?

Topiramate is a prescription-only medication.

It is an anticonvulsant drug. Anticonvulsant drugs are used to control or prevent seizures or convulsions and are also used to ease an ongoing series of seizures.

Topiramate was first approved by the FDA in 1996 for treating seizures. It was again approved by the FDA in 2004 for migraine prevention.

The following dose formats are available:

• Topiramate tablet: 25mg, 50mg, 100mg, and 200mg

• Topiramate capsule: 15mg and 25mg

• Extended-release capsule: 25mg, 50mg, 100mg, 150mg, and 200mg

Topiramate: brand names

Topiramate is also sold under different brand names, including:

• Topamax: oral tablets (25mg, 50mg, 100mg, and 200mg) and sprinkle capsules (15mg and 25mg)

• Qudexy XR¹: extended-release capsules (25mg, 50mg, 100mg, 150mg, and 200mg)

• Trokendi XR²: extended-release capsules: (25mg, 50mg, 100mg, and 200mg)

• Eprontia³: ready-to-use liquid suspension (25mg/ml)

Note this article will focus on generic topiramate. Ask your doctor or pharmacist for more information about any of the brands and formulations listed above.

What is topiramate used to treat?

Topiramate is approved by the FDA as a treatment for seizures in adults and children over two years of age.

The drug can be used to treat different types of seizures, including:

• Primary generalized tonic-clonic seizures — seizures that involve both sides of the brain that are associated with sudden muscle stiffness and repeated jerking movements.

• Partial onset seizures — seizures that start with one-half of the brain (also called focal onset seizures).

• Seizures associated with Lennox-Gastaut Syndrome — this syndrome is rare but severe and can affect young children.

Topiramate is also approved by the FDA to be used as a preventive treatment for migraines.

What You Need To Know About Migraines

How do you take topiramate?

Take topiramate exactly as prescribed. Do not start or stop taking topiramate without your doctor’s guidance. Do not take more or less than your prescribed dose.

Take topiramate by mouth with or without food. It has a bitter taste. Swallow the tablet whole. Don’t crush or split the tablet.

You can swallow the capsule whole or open it and sprinkle it on soft foods like ice cream, pudding, yogurt, applesauce, oatmeal, or custard. Do not chew the medicine; it should be swallowed immediately. Do not save for later use.

It is recommended to take topiramate at the same time every day.

Below, you’ll find the typical adult dosages of topiramate⁴.

Typical topiramate dosage for seizures (when taken alone)

Immediate-release topiramate:

Adults and children (aged ten years and above): The typical starting dose is 25mg by mouth twice per day. The maximum dose is 400mg per day, divided into two 200mg doses.

Extended-release topiramate:

Adults and children (aged ten years and above): The typical starting dose is 50mg by mouth once per day. The maximum dose is 400mg taken once per day.

Typical topiramate dosage for seizures (when taken with other drugs)

Immediate-release topiramate:

Adults (aged 17 years and above): The typical starting dose is 25–50mg by mouth taken once per day. After this, your dose can increase to twice daily. The maximum dose is 200mg taken twice per day (a total of 400mg per day).

Extended-release topiramate:

Adults (age 17 years and above): The typical starting dose is 25–50mg by mouth taken once per day. The maximum dose is 400mg taken once per day.

Typical topiramate dosage to prevent migraines

Immediate-release topiramate:

Adults (aged 12 years and above): The typical starting dose is 25mg taken by mouth once per day in the evening for the first week. After this, your dose can increase to twice per day. The maximum dose is 50mg taken twice per day (a total of 100mg per day).

Extended-release topiramate:

Adults (aged 12 years and above): The typical starting dose is 25mg taken by mouth once per day. The maximum dose is 100mg taken once per day.

Dosages for children

Your child’s doctor will determine the correct topiramate dosage and format depending on their condition, age, weight, and whether they are taking other medications.

Children under 12 years of age should not take topiramate for migraine prevention.

Seeing results

The time topiramate takes to work depends on the condition you are taking it for.

It can take two to four weeks⁵ for topiramate to work fully when taken to treat seizures.

For migraine prevention, you may notice you are getting fewer migraines after one month. However, it can take two to three months for the drug to work fully to prevent migraines.

Potential side effects of topiramate

Topiramate can cause side effects.

Some of the common side effects of topiramate include:

• Drowsiness

• Slow reactions

• Speech problems

• Abnormal vision

• Changes in your sense of taste

• Tiredness

• Dizziness

• Decreased sensation

• Loss of appetite

• Weight loss

• Nausea

• Diarrhea

Talk to your doctor about any side effects you experience. These side effects can be early symptoms of overdose.

Serious side effects

Topiramate can cause serious side effects. The FDA has listed the following risks on the medication label.

Eye problems

Topiramate has been found to cause acute myopia in some cases, which can lead to secondary angle closure glaucoma syndrome. Without any intervention, this could cause permanent loss of vision.

Speak to your doctor if you develop pain in your eyes or blurry vision. They may ask you to stop taking topiramate. Stopping treatment has been found to reverse these eye problems.

Metabolic acidosis

Topiramate may cause metabolic acidosis, a buildup of acid in your body.

Seek medical assistance if you develop the following symptoms:

• Rapid heartbeat

• Hyperventilation

• Tiredness

• Weakness

• Loss of appetite

• Feeling confused and/or headache

• Vomiting or nausea

Kidney stones

Topiramate has been shown to increase the risk of developing kidney stones. The risk of developing kidney stones is higher in men, and they can also affect children.

The FDA recommends hydration to help prevent kidney stones.

Speak to your doctor if you develop the following symptoms:

• Blood in the urine

• Cloudy urine

• Foul-smelling urine

• Severe pain in your lower back on either side

• Consistent stomach ache

• Nausea or vomiting

• Fever-like symptoms, such as chills or high temperature

Suicidal thoughts or behavior

Antiepileptic drugs (AEDs) like topiramate have been found to cause suicidal thoughts or behaviors in some people. These effects have been seen within a week of taking the medication.

Symptoms may include worsening depression, new depression, suicidal thoughts, suicidal behavior, and any changes to your mood or behavior.

High levels of ammonia in the blood

Topiramate may cause hyperammonemia, or high levels of ammonia in the blood. The liver condition, encephalopathy, may also occur. This can cause excess ammonia to travel to your brain.

This serious side effect has been seen more often in people who also take valproic acid (Depakene or Depakote). Valproic acid is another anticonvulsant medication taken to prevent migraines and treat seizures.

Hyperammonemia may not cause symptoms, but speak to your doctor if you experience:

• Changes in behavior

• Disorientation

• Confusion

• Balance, coordination, and speech problems

• Nausea or vomiting

• Headaches

• Stomach pain

Hypothermia

Hypothermia — a drop in core body temperature to less than 35°C (95°F) — may also occur with or without hyperammonemia.

This adverse effect has been seen⁶ with people taking topiramate and valproic acid or phenobarbital, both anticonvulsants.

Symptoms of hypothermia may include:

• Tiredness

• Drowsiness

• Confusion

• Memory loss

• Slurred speech

• Fumbling hands

Cognitive/neuropsychiatric reactions

Topiramate can cause three types of cognitive/neuropsychiatric reactions (reactions relating to brain function).

Alert your doctor if you experience any of the following symptoms:

• Drowsiness

• Fatigue

• Low mood

• Behavioral changes

• Problems with speech or language

• Difficulty concentrating

• Confusion

Decreased sweating and hyperthermia

Topiramate has been seen to cause oligohidrosis and hyperthermia in some people.

Oligohidrosis is a condition characterized by decreased sweating. Hyperthermia is a condition where your body temperature increases to dangerous levels.

Speak to your doctor if you notice decreased sweating or fever-like symptoms, such as a high temperature.

Skin reactions

If you develop a rash while taking topiramate, seek medical help immediately. It could be a sign of a serious skin reaction, like Stevens-Johnson syndrome or toxic epidermal necrolysis.

Long-term use of topiramate

Topiramate is generally safe to take over a long period of time⁷, as long as you take your prescription correctly and follow your doctor’s advice.

Missed doses

If you miss a dose of topiramate, take it as soon as possible. If it’s nearly time to take your next dose, skip the dose you missed and resume your regular schedule. Never take double doses of topiramate just to catch up on a dose you missed.

Consult your doctor and ask for their guidance if you miss more than one dose of topiramate. 

Overdoses

Seek emergency medical help if you think you or someone else has taken too much topiramate.

Symptoms of an overdose may include:

• Shallow, rapid breathing

• Pounding or irregular heartbeat

• Drowsiness

• Dizziness

• Difficulty concentrating

• Blurred vision

• Double vision

• Trouble speaking

• Loss of appetite

• Vomiting

• Stomach pain

• Tiredness

• Coordination difficulties

• Loss of consciousness

• Seizures

• Agitation

• Low mood

Allergy information

It is possible to experience mild to severe allergic reactions when using topiramate.

Symptoms of an allergic reaction may include:

• Rash

• Itchy skin

• Flushed skin

• Swelling of your mouth, tongue, or throat (this may cause trouble breathing)

• Swelling underneath your skin — this usually affects the hands, feet, lips, or eyelids

If you experience an allergic reaction when using topiramate, stop using the medicine and immediately call your doctor. You may be prescribed another type of medication instead. 

What to discuss with your doctor before taking topiramate

Before you start taking this medicine, you should discuss the following things with your doctor if they apply to you:

• Tell your doctor if you are allergic to any medication, including topiramate. Tell them if you have ever experienced an allergic reaction to topiramate in the past.

• Tell your doctor about other medications that you are taking, including both prescription and over-the-counter drugs. Some drugs interact with topiramate and have life-threatening consequences. You can read more about drug interactions below.

• Tell your doctor if you are taking any herbs or supplements. If you intend to start taking them during topiramate treatment, they should be aware of this.

• Tell your doctor about any other medical conditions you may have. Taking topiramate could be dangerous if you have any of the following conditions:

  • Conditions that affect your kidneys

  • Conditions that affect your liver

  • Metabolic acidosis

  • Conditions that affect your bones, like osteopenia, osteomalacia, or osteoporosis

  • Diabetes

  • Eye conditions, like glaucoma

  • Lung conditions, such as asthma or chronic obstructive pulmonary disease (COPD)

  • Depression or mood changes

  • Diarrhea

  • Growth problems

• Tell your doctor if you are pregnant, planning to get pregnant, or are currently breastfeeding.

Stopping topiramate

Stop taking topiramate gradually. Suddenly stopping this medication can increase your risk of seizures or make your seizures more frequent.

Consult your doctor and ask for advice if you want to stop using topiramate. You may be prescribed a gradually decreasing dose to avoid adverse effects.

If you need to stop taking topiramate suddenly, perhaps due to an adverse reaction, you will require close monitoring by a doctor.

Topiramate and pregnancy

Topiramate is listed as a pregnancy category D⁸ medication by the FDA. It is known to harm a fetus when taken by pregnant women.

It can increase the risk of cleft lip or cleft palate. These problems usually occur during the first trimester.

Babies exposed to topiramate during pregnancy may also be small for gestational age (SGA). This is where the baby is smaller in size than what is considered normal for their gestational age. SGA in babies exposed to topiramate during pregnancy appears to depend on the mother’s dose. It is more likely to occur if the mother takes topiramate in the third trimester.

You should also consider the risk of metabolic acidosis as a serious side effect of topiramate. During pregnancy, this could cause reduced growth and oxygen levels in the baby. It may also make delivery more dangerous for the baby. Newborn babies should be monitored for metabolic acidosis after delivery if the mother took topiramate during pregnancy.

If you are using this medicine to treat seizures, tell your doctor if you are pregnant or planning to become pregnant. Your doctor will likely prescribe an alternative drug, as seizure management during pregnancy is very important to the health of the mother and fetus.

Topiramate and breastfeeding

Topiramate is known to pass into breast milk. There are reports that it causes babies to experience excessive sleepiness and diarrhea.

Let your doctor know if you are breastfeeding or are planning to breastfeed so that you can be aware of the risks and be advised by your doctor.

Interactions with other drugs

Topiramate can interact with different drugs, including prescription, non-prescription, and herbal medicines.

These are some of the drugs that can interact with topiramate:

• Other anticonvulsant medications

  • Phenobarbital

  • Acetazolamide (Diamox)

  • Valproic acid (Depakene or Depakote)

  • Phenytoin (Dilantin or Phenytek)

  • Pregabalin (Lyrica)

  • Carbamazepine (Epitol, Equetro, Tegretol, and Carbatrol)

  • Lamotrigine (Lamictal)

  • Zonisamide (Zonegran)

• Oral contraceptives containing estrogen — topiramate may reduce their efficacy and cause breakthrough bleeding

• Antihistamines, including:

  • Diphenhydramine (Benadryl, Nitol, and others)

  • Cetirizine (Zyrtec, Aller-Tec, and Alleroff)

  • Clemastine (Dayhist Allergy and Tavist)

  • Brompheniramine (Ala-Hist IR, J-Tan, and Veltane)

• Anticoagulants (blood-thinning drugs), such as warfarin (Coumadin or Jantoven)

• Diuretics (water pills), such as hydrochlorothiazide (Oretic and Microzide)

• Diabetes medications, including:

  • Pioglitazone (Actos)

  • Metformin (Glucophage, Fortamet, and others)

  • Glyburide (DiaBeta and Glynase)

• Central nervous system (CNS) depressants (this interaction has not been extensively studied, but topiramate can cause CNS depression, so caution is advised), including:

  • Opioid pain relievers

  • Sedatives

  • Benzodiazepines

  • Alcohol

• Medications used to treat mental health conditions, including:

  • Lithium (Lithobid)

  • Amitriptyline

  • Aripiprazole (Abilify)

  • Quetiapine (Seroquel)

  • Duloxetine (Cymbalta)

  • Escitalopram (Lexapro)

  • Citalopram (Celexa)

  • Alprazolam (Xanax)

• Drugs used to treat heart conditions, such as digoxin (Digitek, Lanoxin, and others)

Note that this is not a complete list of drugs that interact with topiramate. It is essential that you tell your doctor about any drugs you are taking or plan to start taking so harmful interactions can be avoided.

Speak to your doctor about any other drugs you are currently taking. If there is an interaction, your doctor will advise you not to take either drug or adjust your dosage.

Clinical trial history

1996: The FDA first approves topiramate as Topamax oral tablets.

1998: Topamax capsules and sprinkle capsules are approved by the FDA.

2006: Generic topiramate is first made available.

2013: The FDA approves Trokendi XR (extended-release topiramate).

2014: Qudexy XR (extended-release topiramate) is approved by the FDA.

Tips and advice for taking topiramate

The following tips and advice can help you take topiramate safely and effectively:

• It is best to take topiramate during the evening, as it causes sleepiness. If you need to take it twice a day, take one dose in the morning and another in the evening.

• Topiramate can cause drowsiness. It is important to first assess yourself before engaging in activities that require focus, such as sports and driving.

• Avoid drinking alcohol when taking topiramate. Alcohol increases the risks of dangerous side effects.

• Don’t stop taking topiramate suddenly. Only stop taking the drug with your doctor’s guidance.

• Many drugs interact with topiramate. Ensure your doctor knows which other medications you are currently taking to help avoid dangerous interactions.