Topamax is a hugely popular drug used to help prevent epilepsy and migraine. It’s the most commonly prescribed migraine medication in the United States.
So what is Topamax?
It’s an antiepileptic medicine and is also known as an anticonvulsant. These class of drugs were initially formulated to prevent seizures in those afflicted with epilepsy.
Topamax is a brand developed by Johnson & Johnson, which holds the patent for their formulation approved in 1996. Once this patent expired, its generic versions were available in the form of topiramate. At the time of approval in mid 2009, there were more than 18 different generic manufacturers.
Brand names for Topiramate
Topamax Sprinkle, Topamax, Topiragen, Qudexy XR, Trokendi XR
Trokendi XR and Qudexy XR are both relatively new extended release topiramate formulations.
You can get them in three formats:
- Sprinkle capsules- 15 and 25 mg
- Tablets- 25 to 200 mg
- Capsule (Extended Release)- 25 to 200 mg
Is prescription necessary for Topamax (topiramate)?
How does this migraine medication works?
Well, we’re still not clear on this!
Topiramate was initially formulated for treating epilepsy. The epilepsy patients showed good improvement in their migraine condition in many case studies and from there on tests were conducted on migraine patients specifically. This drug has not been designed to take on migraine but it is definitely effective in preventing migraine.
Both migraine and epilepsy share many biological and clinical features so it’s no surprise to find many anticonvulsant medications showing therapeutic benefits for both indications.
Many scientific studies show that topiramate can reduce brain hyperexcitabiltiy, which is the biggest reason to provoke many migraine attacks in susceptible people.
The way the drug works is often referred to in clinical papers as its unique mechanism of action. So topiramate’s exact mechanism of action involves:
- Augmenting the activity of neurotransmitter gamma-aminobutyrate.
- Blocking maximum voltage dependent sodium channels
- Inhibiting the carbonic anhydrase enzyme
- Antagonizing the AMPA/Kainite subtype of the glutamate receptor
This essentially shows the way Topamax blocks some neurotransmitters or pathways in the brain as well as changing or alterning how they behave.
How effective is topiramate (Topamax)?
Well, topamax can definitely help in preventing migraine attacks but never treats them.
It gets “Grade A” from European and US authorities. It’s the highest rating that any treatment can receive. It’s a reflection of the depth of research evidence and the efficiency of the results according to the clinical evidence.
In collective analysis of research studies meta analysis is used to summarize the results of studies.
This work has been done on topiramate for prevention of migraine attacks in adults. In an extensive study by The Cochrane Collaboration, around 19 studies were reviewed and it was found that it did reduce the frequency of attacks per month versus placebo. They also found that migraine patients were around twice likely to reduce the attacks by 55 percent or more with the use of topiramate than with placebo.
So this review’s scientific conclusion was that topiramate at 100mg/day dosage is effective and also reasonably tolerated in adult patients.
Though you get some positive results by using topiramate, it also causes some side effects that are generally mild.
It can cause birth defects and is not suitable for some people. Side effects are more likely to increase as its dose increases from 50-100 mg.
Some side effects include taste perversion, pins and needles, fatigue, sinusitis, upper respiratory tract infection, anorexia, sinusitis, diarrhea, nausea, dizziness, injury, drowsiness or sleepiness, difficulty with memory, joint pain, language problems, insomnia, hypoestheisa, pharyngitis, abdominal pain, anxiety, dyspepsia, viral infection, nervousness, uringary tract infection, and itchiness.
Some symptoms you may not recognize are defined below:
Dyspepsia – uncomfortable sensation or pain in the gut including reflux
Hypoesthesia – numbness or reduced sense of touch
Psychomotor slowing- slowing of physical activity and though such as speech and/or movement
Gastroenteritis – commonly termed “gastro”. An infection upsets the stomach
Please note that this is not a full list of potential side effects. There are many other side effects that patients may be vulnerable to which is why it’s necessary for migraineurs to speak to their doctor if considering whether topiramate may be the right medication to address pain.
When prescribed by a doctor after taking into account your medical history, topiramate is considered safe and is also approved by FDA and many other regulatory bodies around the world.
However, there are important precautions and warning that come along with this treatment.
For instance, you should never stop this medication suddenly. This medication needs gradual withdrawal with staged reductions in your dose. If you suddenly stop taking medications then seizures may occur in those who do not normally experience them.
Topiramate may have some uncommon but serious side effects:
- Topamax can cause kidney stones. Therefore doctors advise patients to drink lots of water throughout the day to help prevent kidney issues.
- Hyperammonemia, a condition which refers to high ammonia levels in the blood.
- Eye issues, including acute myopia, where one may have difficulty in seeing clearly and may be accompanied by fluid build-up in the eye. This can even lead to blindness if not treated in time.
- Metabolic acidosis, where levels of acid increases abnormally in the blood
- Ideation or suicidal behavior can increase in patients taking Topamax
- Encephalopathy, which is a brain disease
- Topamax also leads of fetal toxicity. It can induce birth defects in the unborn baby of pregnant women. It’s also not good for mother who’re planning to become pregnant or are nursing mothers whilst using Topamax.
Major Drug Interactions
Topiramate, like various other medications, may interact with other medications and may have dangerous consequences. It’s important to ensure your doctor has complete list of everything you’re currently taking.
Interactions of Topamax (topiramate) include:
- Central Nervous System Depressants
- Other antiepileptic drugs
- Oral contraceptives
- Carbonic Anhydrase Inhibitors (eg. zonisamide or acetazolamide)
- Hydrochlorothiazide (HCTZ)
These people should avoid topiramate or Topamax:
- Kids under 12 have not been evaluated for the effectiveness or efficacy of Topamax for migraine prevention. It’s best for kids to avoid this medication.
- Women who’re pregnant, nursing mothers or planning to get pregnant.
- Patients with renal failure or undergoing hemodialysis.
Dosage ranges from 25-200 mg per day.
With topiramate it’s best to “go slow, start slow”. It’s initiated with 25 mg/ day with slow but gradual increase to maximum tolerated dose.
Maximum tolerated dose is the amount you can take without worrying about adverse events getting worse or side effects than any benefits derived from the treatment.
The maximum dose of 200mg has been researched frequently during clinical trials. Interestingly, epilepsy patients have been successfully researched for dosage up to 400mg.
In the United States generic topiramate is covered by most insurance and Medicare plans. One month supply (60 tablet pack) of 50mg is available at $10-$15 per pack.
In Canada, the 50mg 120 tablet pack will cost $288 USD. In fact, generic can be bought at $114.90 USD.
In United Kingdom, you can get one month supply at £31.69.
In Australia, Topamax has been listed on the national PBS scheme and it can be bought at $25/02 per pack of 60 tablets. The generic version of the same quality is available at $14.99.
Important things to remember when taking medications
Overdosing is when you take more medication than prescribed dose. So it is important to avoid overdose. If you feel overdose has occurred due to your visit to emergency department of the hospital. Take the pack and medication container with you even if it’s empty. It’s better to be safe than sorry!
The medication which doctor has prescribed to you is just for you. Never share it with others who may have symptoms similar to your condition. Your treatment can cause serious issues with others who may have a different health profile, history or those who are using other medications.
Dispose all out of date medications as they can have unintended consequences if taken.
If you’re having dental treatment or operation, tell all about the treatments you’re currently taking.
If there are any questions in your mind about your treatment, ask your doctor or pharmacist.
Never stop or change your treatment or dosage without consulting your doctor.
Around 33 percent of patients who take topiramate report moderate improvement in their condition with a further 14-37 percent experiencing good improvement depending upon the source.
This observation is quite close to the systematic review that emerged from a clinical research in 2012 where twice as many migraineurs reported 49 percent reduction in headache frequency versus placebo.
Topiramate side effects are common. Some users may note some weight loss, which is a welcome side effect! Other side effects include word fishing or tingling which may not be considered severe but some people cannot tolerate memory issues or brain fog. Every person is unique in the side effects they experience. Some may not experience any, whilst others may find many of these intolerable.
If you’ve the stamina to tolerate topiramate side effects, then it could be considered a useful and effective migraine treatment.