Because it has been proven in studies to be highly effective as a prophylactic migraine medication, it is approved for this use by the U.S. Food and Drug Administration (FDA), as well as by drug regulatory agencies in numerous other countries.
Besides Topamax, topiramate is sold under two other brand names—Qudexy XR and Trokendi XR—and is also available in a generic form.
How It Works
Topamax blocks channels in the body that deliver electrical impulses to nerve, muscle, and brain cells. This may enhance the activity of a neurotransmitter known as gamma-aminobutyric acid (GABA), which is involved in regulating motor control, vision, and anxiety.
Researchers aren’t certain how this process works to prevent migraine headaches or seizures, but it does so effectively, and it is considered safe.
Dosage
Topamax is available in 25 milligram (mg), 50 mg, 100 mg, and 200 mg tablets. It’s also available in 15 mg and 25 mg capsules that contain a powdered form of the medication. The capsules can be swallowed whole or opened up and sprinkled onto soft food.
Based on research comparing the effectiveness of 100 mg vs. 200 mg per day of Topamax for preventing migraines, the target dose for most people is 100 mg (50 mg taken twice a day). The dosage range recommended in guidelines set by the American Headache Society and the American Academy of Neurology is 25 mg to 200 mg per day.
If your healthcare provider prescribes this medication for you, they likely will start you on a relatively low dose of 25 mg once a day for a week, and then increase your dose by 25 mg per week until you’re taking a therapeutic dose.
Gradually titrating the dose of Topamax in this way will help to prevent side effects. It takes time for Topamax to work when you first start using it. It may take 1 month for your migraine attacks to become less frequent and 2 to 3 months for Topamax to become fully effective.
Likewise, if you’ve been taking Topamax and would like to quit, it’s advisable to first consult with your healthcare provider, who will guide you through tapering down your dose to lower the risk of side effects that can occur if you stop cold turkey. Withdrawal seizures are a potential side effect of stopping abruptly, even if you do not have epilepsy.
Side Effects
Topamax has been shown to cause a host of side effects. Most are mild to moderate in severity and temporary; as your body gets used to the medication, some side effects are likely to disappear. Call your healthcare provider if they don’t.
There also are a number of potentially serious side effects associated with Topamax, all of which you should let your healthcare provider know about right away.
Complications
In addition to side effects, Topamax has been linked to several serious complications:
Metabolic acidosis: This is a build-up of acid in the blood caused by an imbalance of bicarbonate in the body. Symptoms include nausea, vomiting, fast breathing, and lethargy. This condition may cause kidney stones, so it’s important to drink plenty of fluids while on Topamax. If left untreated, metabolic acidosis can lead to coma and death. It most often occurs in children 15 and under. Glaucoma: Symptoms usually appear within a month of starting treatment and may be recognized by the sudden blurring of vision, eye pain, redness, and abnormally dilated pupils. Kidney failure: This is most likely to occur in folks over age 65 who have an underlying kidney disorder. For this reason, people taking Topamax should have routine kidney function tests. Osteoporosis Suicidal thoughts and behavior Cognitive/neuropsychiatric reactions: use caution when operating machinery, including cars. Depression and mood problems may occur. Alcohol or marijuana (cannabis) can worsen these effects.
Interactions
It’s possible that taking Topamax along with other medications could lead to problems. Your healthcare provider will ask you what other drugs you take before prescribing Topamax; this means over-the-counter and prescription medications, as well as nutritional and herbal supplements and natural remedies.
The medications most likely to interact with Topamax include:
Diamox (acetazolamide) Amitriptyline Antidepressants Antihistamines Lanoxin (digoxin) Microzide, Oretic (hydrochlorothiazide) Lamictal (lamotrigine) Lithobid (lithium) Medications for motion sickness, ulcers, or urinary problems Fortamet, Glucophage, and others (metformin) Other anti-seizure medications
Contraindications
Be careful about using Topamax if you’re trying to conceive, are expecting a baby, or you’re breastfeeding.
Among others who should be cautious about taking Topamax or who shouldn’t take it all are those who have:
Metabolic acidosis Kidney stones A history of self-harm or suicidal thoughts Conditions in which bones are brittle or soft (osteopenia, osteomalacia, or osteoporosis Diabetes Glaucoma Any condition that affects breathing, such as asthma Depression or another mood disorder A growth problem Diarrhea
A Word From Verywell
If your healthcare provider prescribes Topamax for you, it’s vital that you take it correctly and report any side effects without delay.
And do not stop taking Topamax abruptly, unless there is an urgent need and you are under the guidance of your healthcare provider. For most people who get episodic migraine headaches, Topamax is safe, effective, and may well be the key to having fewer headaches per month.
