Understanding your Topamax dose: Migraines vs. seizures

Dosages for preventing migraine headaches

For migraine prevention, you’ll start treatment by taking a low dose, then your doctor will gradually increase your dose over the next few weeks. The recommended dosages are the same for adults and children ages 12 years and older.

Topamax’s recommended maintenance dose for migraine prevention is 50 mg taken twice per day (100 mg per day).

In clinical trials, the highest dosage studied for migraine prevention was 200 mg/day.

Dosages for seizure treatment

Topamax is approved to treat certain types of seizures. Your dosage will vary based on whether you’re taking Topamax on its own or with another medication.

• For treating focal onset seizures or generalized tonic-clonic seizures, your doctor may prescribe Topamax alone or with other medications for seizures.
• For treating seizures due to Lennox-Gastaut syndrome, they will prescribe Topamax with other medications for treating seizures. Topamax is not prescribed on its own for this condition.

Dosages for seizure treatment when Topamax is taken alone

For adults and children ages 10 years and older, the typical starting dosage of Topamax is 25 mg twice per day. Then, your doctor will gradually increase your dose over the first weeks of treatment.

The maintenance dosage is 200 mg taken twice per day (400 mg/day).

Dosage for children ages 2 to 9 years

Topamax can be taken on its own to treat focal onset and generalized tonic-clonic seizures in children ages 2 to 9 years. Starting dosages are slowly increased.

• Week 1: The dosage will be 25 mg once per day (in the evening).
• Week 2: The dosage will likely be increased to 25 mg in the morning and 25 mg in the evening.
• Weeks 3 to 7: The total daily dose may be increased by 25 to 50 mg/day as needed each week.

Your child’s doctor may continue to increase their dose to the highest maintenance dosage as shown in the following table. This is based on body weight in kilograms (kg). (One kg is about 2.2 pounds [lb].)

Dosages for seizure treatment when Topamax is used with other medications

For adults and children ages 17 years and older, the starting dose is 25 to 50 mg/day.

The dose is then increased by 25 to 50 mg/day each week until the most effective dose is reached. The recommended total daily doses are:

• 200 to 400 mg/day for focal onset seizures or seizures caused by Lennox-Gastaut syndrome
• 400 mg/day for primary generalized tonic-clonic seizures

Dosages for children ages 2 to 16 years

When Topamax is taken with other seizure medications in children ages 2 to 16 years, the dosage is based on body weight. It’s also adjusted over time.

• For the first week of treatment, the highest possible starting dose is 25 mg/day, taken once in the evening. Your child’s dose will be 1 to 3 mg of Topamax per kg of body weight (mg/kg) per day, up to the maximum of 25 mg/day.
• The dose will then be increased by a daily total of 1 to 3 mg/kg. It’s likely that your child’s doctor will change the dose from once daily in the evening to twice daily. This total daily dose will be split equally between the two doses.
• The recommended maintenance dosage is 5 to 9 mg/kg per day. This daily dose is divided into two doses, with one in the morning and one in the evening.
• The maximum total daily dose is 400 mg/day.

How to take Topamax

You should take Topamax exactly as directed by your doctor.

If you’re prescribed Topamax tablets:

• Swallow them whole.
• Do not crush or chew them.

Topamax sprinkle capsules can be swallowed whole or opened. If it’s easier for you to open them:

• The sprinkles can be added to a teaspoon of soft food, such as applesauce. Be sure to consume this immediately.
• You should not chew the sprinkles.
• You should not prepare doses with food in advance. This can affect how the drug is absorbed by your body and prevent you from getting your dose as prescribed.
• After taking the sprinkles, you should drink a beverage, such as water, to make sure you swallow them all.

Don’t stop Topamax abruptly

Stopping Topamax suddenly can increase the number of migraine days or increase the risk of seizures. If you need to stop taking Topamax, talk with your doctor. They can recommend how to safely stop the drug.

Frequently asked questions

Missed dose

Missing a dose of Topamax is not known to cause side effects. However, missing a dose of Topamax may cause you to have symptoms of the condition you’re taking it to treat.

If you miss a single dose of Topamax, take it as soon as you remember. If you’re scheduled to take your next dose within 6 hours, skip the missed dose and take your next dose as usual. Do not “double up” on doses.

Topamax and overdose

Do not take more Topamax than your doctor prescribes, as this can lead to harmful effects. Symptoms of a Topamax overdose can include:

• convulsions (jerky muscle movements)
• fatigue
• difficulty speaking or with speech
• double or blurred vision
• problems thinking clearly
• coordination problems
• fainting
• low blood pressure
• abdominal pain
• feeling agitated
• dizziness
• feeling sad or depressed

What to do if you take more than the recommended amount of Topamax

Call your doctor right away if you believe you’ve taken too much Topamax. Another option is to call Poison Help at 800-222-1222 or use its online tool. If you have severe symptoms, immediately call 911 (or your local emergency number) or go to the nearest emergency room.

Next steps

Now that you’ve read a little bit about Topamax’s dosages, it can be helpful to establish a safe routine:

• Set reminders: Consistent blood levels are important for Topamax to work effectively. Set daily phone alarms or use a pill organizer to take it at the same time each day.
• Know the form: Check whether you have tablets or sprinkle capsules, so you know how to take your dose properly.
• Have a missed-dose plan: It can be helpful to make a note of what to do if you miss a dose. You can add the details from this article to your notes app.