Long-term side effects of Topamax

In this article:

• What are the most common side effects of Topamax?
• What are the most serious side effects of Topamax?
• Are there any Topamax side effects long-term?
• How to manage Topamax side effects
• Topamax alternatives

In this article

• What are the most common side effects of Topamax?
• What are the most serious side effects of Topamax?
• Are there any Topamax side effects long-term?
• How to manage Topamax side effects
• Topamax alternatives

Topamax (topiramate) is a brand-name prescription drug that’s approved by the Food and Drug Administration (FDA) to treat certain types of epileptic seizures in people at least 2 years old and to prevent migraine in people at least 12 years old. It’s also prescribed off-label to promote weight loss and treat certain mental and behavioral health conditions. Topamax can cause side effects that patients should be aware of, and some side effects may be long-term. Here’s what to expect and how to reduce the risk of negative side effects. 

What are the most common side effects of Topamax?

In people with epilepsy, the most common side effects of Topamax include:

• Paresthesia (a tingling, prickling, or numb feeling in the skin)
• Loss of appetite 
• Weight loss
• Speech difficulty
• Fatigue and drowsiness
• Dizziness 
• Nervousness
• Psychomotor slowing (e.g., delayed reaction times, slowed thinking, slower gait)
• Vision problems
• Fever

The following side effects are common in people who take Topamax to prevent migraine:

• Paresthesia
• Loss of appetite
• Weight loss
• Memory problems
• Changes in sense of taste
• Diarrhea
• Decreased sense of touch
• Nausea
• Abdominal pain
• Upper respiratory tract infection

Many Topamax side effects are dose-dependent, meaning they’re more likely to occur at higher doses. 

In clinical trials, 21% of participants aged 16 and older stopped taking the highest dose of Topamax due to intolerable side effects like memory problems, fatigue, weakness, insomnia, drowsiness, and a pins-and-needles feeling. 

People had less trouble with Topamax side effects at lower doses. At 200–400 mg per day, only 11% of patients discontinued the drug. 

What are the most serious side effects of Topamax?

Janssen Pharmaceuticals, the manufacturer of Topamax, warns about these severe side effects on the prescribing label: 

• Serious eye problems, which can cause blurred vision, decreased vision or loss of vision, and eye pain and redness.
• Decreased sweating can cause the body to overheat.
• Metabolic acidosis, or a buildup of acid in the blood, can cause hyperventilation, irregular heartbeat, kidney stones, osteoporosis, and more.
• Suicidal thoughts and behaviors
• Cognitive problems can take many forms, such as memory, language, or speech problems, general confusion, poor concentration, and slow movements or reaction times.
• Psychiatric/behavioral disturbances, like depression or other mood disorders, tend to happen at higher Topamax doses.
• Fatigue and drowsiness are more common when Topamax is taken with at least one other antiepileptic drug.
• Congenital disabilities caused by Topamax include small weight for gestational age, cleft palate, cleft lip, and other malformations. 
• Seizures can occur when people with epilepsy abruptly stop taking Topamax.
• Bone mineral density can decrease, which increases the risk of fractures.
• Slow growth has been reported in children who take Topamax. 
• Stevens-Johnson syndrome and toxic epidermal necrolysis are widespread and potentially fatal skin infections that may occur while taking Topamax.
• Hyperammonemia, or a build-up of ammonia in the blood, can sometimes affect the brain.
• Kidney stones occur in people taking Topamax at a rate two to four times greater than in the general population.
• Hypothermia, a dangerous drop in body temperature, is more likely to occur when Topamax is taken with valproic acid. 

“Most Topamax side effects are not permanent and often improve over time or after discontinuation,” says Sharon Batista, MD, a board-certified psychiatrist who prescribes Topamax off-label for mood stabilization and eating disorders. “With appropriate medical supervision, serious or permanent complications are rare.” 

Are there any Topamax side effects long-term?

Yes, some Topamax side effects are associated with long-term use, including kidney stones, bone loss, poor growth rates in children, and organ damage. 

Your healthcare provider should routinely screen for long-term side effects of Topamax through eye exams, blood tests, urinalyses, and bone density tests. 

Here’s what they’ll be looking for:

• Eye problems or vision changes that may indicate glaucoma, which can lead to a permanent loss of vision if not treated
• Low bone mineral density, which can increase the risk of fractures at all ages and may affect children’s growth rate
• Too much acid in the blood, a potentially fatal condition that can cause organ damage and muscle weakness, among other symptoms
• Too much ammonia in the blood, another potentially fatal condition that can damage organs and cause confusion
• Crystals, blood, or a pH imbalance in urine, which can help diagnose kidney stones

Zishan Khan, MD, a board-certified psychiatrist with Mindpath Health, says cognitive dysfunction is another possible long-term side effect of Topamax. “Often described as word-finding difficulty, memory issues, or general mental fog, it can appear within weeks of starting treatment and may potentially persist for the duration of use. In some cases, especially after long-term exposure, these cognitive issues can linger even after discontinuation, though they are typically reversible over time.” 

Weight loss can also occur with prolonged use of Topamax. Sometimes it’s prescribed off-label for this purpose.  

How to manage Topamax side effects

Managing Topamax side effects starts with a gradual titration schedule. Your provider should start you on a low dose—usually 25 mg per day for adults—and gradually increase the dose each week. “This significantly reduces the risk of cognitive side effects and paresthesia,” Dr. Khan says.

Other tips for managing Topamax side effects include:

• Drinking plenty of water to prevent kidney stones
• Eating smaller, more frequent, and nutritious meals throughout the day to combat nausea and weight loss
• Taking Topamax with food to soothe gastrointestinal discomfort
• Staggering the timing of other medications that affect the central nervous system or have a similar side effect profile

Tell your healthcare provider about any adverse effects you notice while taking Topamax. “Routine check-ins and open communication with the prescribing physician are key to managing side effects before they become problematic,” Dr. Khan says. 

When to stop taking Topamax

Talk to a healthcare professional immediately if you notice eye pain or blurred vision. This can be a sign of a serious eye problem, which can cause irreversible vision loss if not treated right away. Discontinuing Topamax right away can prevent further eye damage. 

You should also seek medical attention right away if you have skin pain or a rash, blistering or peeling skin, burning eyes, or fever. It could be Stevens-Johnson syndrome or toxic epidermal necrolysis. Quickly (but safely) stopping Topamax is critical for fighting this potentially fatal infection.

Due to the risk of harm to an unborn baby, your healthcare provider may also recommend stopping Topamax treatment if you become pregnant.

However, aside from these urgent cases, it’s not safe to suddenly stop taking Topamax without gradually lowering the dose. For example, if you have a bothersome side effect that is not serious, your healthcare provider may advise you to gradually decrease the dose. “Abrupt Topamax discontinuation can trigger withdrawal symptoms like irritability, dizziness, and worsening of the underlying condition,” Dr. Batista says. “The dose should always be tapered under medical supervision.”

Topamax alternatives

In clinical trials, 21% of adult participants stopped taking Topamax due to intolerable side effects. The risks of any medication shouldn’t outweigh the benefits, so if your quality of life is affected by tingling in your arms and legs, fatigue, nausea, attention problems, insomnia, or other side effects, it’s worth talking to your healthcare provider about Topamax alternatives. 

Alternative epilepsy treatments

When it comes to controlling epileptic seizures, your healthcare provider has more than a dozen Topamax alternatives to choose from. However, Dr. Khan suggests asking about two in particular:

• Keppra (levetiracetam)
• Lamictal (lamotrigine) 

Based on clinical trial data, levetiracetam appears to be more tolerable than Topamax and associated with fewer long-term side effects. Dr. Khan says levetiracetam is an effective anticonvulsant but can sometimes cause irritability or mood changes. 

Lamotrigine shares some side effects with Topamax, such as a risk of vision problems and life-threatening rashes. But lamotrigine also offers similar benefits to Topamax because it doubles as a mood stabilizer.

Alternative migraine treatments

If you’re looking for a medicine to prevent migraine, Dr. Khan says the following are popular options with different side effect profiles than Topamax:

• Propranolol 
• Amitriptyline
• Aimovig (erenumab-aooe)

Propranolol is a beta blocker that’s FDA approved to reduce high blood pressure, but it’s also prescribed off-label to prevent migraine headaches. “It has fewer cognitive side effects than Topamax, but can cause fatigue or exacerbate asthma,” Dr. Khan says. 

Amitriptyline is a tricyclic antidepressant that’s prescribed off-label for chronic pain management and migraine prevention. “It’s effective but may lead to sedation and weight gain,” Dr. Khan says. Like Topamax, amitriptyline may cause suicidal thoughts or behaviors.

Finally, Aimovig is a brand-name injectable medication that’s FDA approved to prevent migraine headaches. It belongs to a class of drugs called CGRP inhibitors, which Dr. Khan describes as newer migraine treatments with fewer side effects. The prescribing information for Aimovig lists just two common side effects: injection site reaction and constipation. On the downside, CGRP inhibitors tend to be pricey because there are no generic versions available yet. 

Other alternatives

There is a wide variety of mood stabilizers and weight loss drugs that can be prescribed instead of Topamax. Talk to your healthcare provider if you’re considering switching from Topamax to another medication. 

Bottom line

Taking Topamax long-term could increase your risk of problems such as kidney stones, organ damage from too much acid or ammonia in your blood, fractures or osteoporosis from decreased bone density, cognitive dysfunction, and weight loss. In children, prolonged Topamax use can slow growth. 

Your healthcare provider will run periodic tests to make sure you remain healthy while taking Topamax and can help you find an alternative if needed. Don’t stop taking Topamax without talking to your healthcare provider due to the risk of withdrawal symptoms.