Topiramate: 6 things you should know
Medically reviewed by C. Fookes, BPharm Last updated on Nov 15, 2018.
1. How it works
- Topiramate reduces the frequency and duration of seizures and is used in the treatment of certain types of epilepsy. It also prevents the development of migraine headaches.
- Experts aren't sure exactly how topiramate works in either epilepsy or to prevent migraines but research suggests it dampens down excessive nerve firing, enhances the actions of GABA, and blocks the effects of other chemical messengers.
- Topiramate belongs to the class of medicines known as carbonic anhydrase inhibitors or carbonic anhydrase inhibitor anticonvulsants. It may also be called an anticonvulsant.
- May be used as sole therapy or in addition to other medications for the treatment of partial onset or primary generalized tonic-clonic seizures in adults and children over the age of two.
- May be used in addition to other medications for the treatment of Lennox-Gastaut syndrome in adults and children over the age of two.
- May be used to prevent the development of migraine headaches in adults and children aged 12 years and older.
- Does not require monitoring of blood concentrations.
- Generic topiramate is available.
If you are between the ages of 18 and 60, take no other medication or have no other medical conditions, side effects you are more likely to experience include:
- Drowsiness which may affect your ability to drive or operate machinery. Avoid alcohol.
- Sudden eye pain and decreased vision associated with or without glaucoma have been reported; symptoms may occur in both children and adults and typically start within 1 month of starting therapy. Seek urgent medical attention; drug discontinuation may be necessary to avoid permanent vision loss.
- Reduced ability to sweat and increased body temperature. This is more likely to occur in children, especially in hot weather or when used in conjunction with other drugs that also raise body temperature (such as acetazolamide or hyoscine). Hypothermia (low body temperature) has also been reported when topiramate is taken in conjunction with valproate.
- Confusion, difficulty with concentration/attention, forgetfulness, speech or language difficulties, depression or mood problems, flushing, fever, tiredness, fatigue, weight decrease and tingling of the extremities are common side effects. May cause hypothermia or hyperammonemia with or without encephalopathy; risk is greater with concomitant valproate use.
- The risk of kidney stones in people taking topiramate in two to four times higher than the general population.
- May cause disturbances in bicarbonate levels leading to a metabolic acidosis; caution when used with metformin.
- Rarely, has been associated with sudden unexplained death.
- Should not be stopped suddenly when used to treat epilepsy. Rather, the dosage should slowly be reduced.
- Topiramate will not treat a migraine, it will only help prevent one from developing.
- As with other antiepileptics, topiramate may increase the risk of suicidal thoughts or behavior; monitor for worsening depression or mood changes.
- Dosage may need reducing in people with kidney or liver disease.
- May interact with several other drugs including seizure medications (such as phenytoin, carbamazepine), oral contraceptives, lithium, and pioglitazone.
- Reliable contraception should be used if topiramate is taken by women of childbearing age as the use of topiramate has been associated with cleft lip or palate in the developing baby.
Notes: In general, seniors or children, people with certain medical conditions (such as liver or kidney problems, heart disease, diabetes, seizures) or people who take other medications are more at risk of developing a wider range of side effects. For a complete list of all side effects, click here.
- Can be taken with or without food.
- Tablets have a bitter taste; do not break.
- Topiramate is usually started at a low dosage and then titrated up slowly until an effective dose is reached (experts suggest increasing by 25 mg/day every week). Your doctor will explain this to you.
- Topiramate should be discontinued slowly to minimize the potential for seizures unless a rapid withdrawal is justified. Dosage should be titrated up slowly until effective dose is achieved (experts suggest increasing by 25mg/day every week).
- Seek urgent medical attention if you develop eye pain, blurred vision or visual disturbances while taking topiramate.
- Also, report any changes in mood or the development of depression or suicidal thoughts to your doctor.
- Discontinue slowly to minimize the potential for seizures, unless rapid withdrawal has been advised by your doctor.
- Keep up your fluid intake and avoid dehydration as topiramate can increase the risk of kidney stones developing. Topiramate may also make you sweat less or give you a fever. Contact your doctor if your fever does not go away, you develop abdominal pain with or without vomiting, or you are unable to sweat.
- Do not drive or operate machinery or perform other hazardous tasks if topiramate makes you dizzy or drowsy. Alcohol can potentiate these effects so should be avoided.
- Extended-release topiramate (Trokendi XR) should not be used in children aged less than ten when used as the sole medication, or less than six when used in addition to other anticonvulsants.
- Topiramate should not be taken during pregnancy or while breastfeeding.
6. Response and Effectiveness
- Peak concentrations of topiramate are reached within two hours of oral administration. Some effects apparent within a few days of taking topiramate; however, it may take up to eight weeks before the full effects seen.
- The sprinkle formulation of topiramate and the immediate-release tablet formulation of topiramate are bioequivalent (this means they are absorbed to the same extent and are interchangeable).
Topiramate [Package Insert] Revised: 07/2017. Cipla USA Inc. https://www.drugs.com/pro/topiramate.html
Remember, keep this and all other medicines out of the reach of children, never share your medicines with others, and use topiramate only for the indication prescribed.
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