Topamax
Topiramate
Drug Class and Mechanism of Action of Topamax
Topamax is an oral anti epileptic medicine. It is used to prevent the seizures of epilepsy. It is used primarily among patients who are not controlled by other anti-epileptic drugs (about 1 in 4 Americans with epilepsy has seizures that resist treatment with other anti-epileptic drugs).
Seizures are due to the abnormal activity known as "firing" of nerves in the brain, which later on spreads to smaller or larger portions of the brain. The exact mechanism of action of Topamax is unknown, but many scientific studies suggest that it may alter neurotransmitters (these are chemicals that nerves manufacture and use to communicate with other nearby nerves) within the brain. By altering the production or action of the neurotransmitters, Topamax may suppress the abnormal activity ("firing") of the nerves in the brain that cause the seizures or may prevent the abnormal activity from spreading to other nerves. Other studies suggest that Topamax may suppress the nerves directly (i.e., not by altering neurotransmitters) and make them less likely to “fire”.
Therapeutic Uses of Topamax
Topamax is used in the prevention of seizures of epilepsy. Seizures of epilepsy can be classified as either partial (where it involves only a small portion of the brain) and generalized (where it involved most of the brain). Topamax is generally used in combination with other anti-seizure (anti epileptic) drugs in adults as well as in children aged 2 to 16 years with partial seizures or generalized tonic-clonic seizures (in which there is prolonged contraction of the muscles of the body that causes rigidity as well as jerking motions).
Topamax is also used in patients of two years of age and older with seizures associated with the Lennox-Gastaut Syndrome (a severe form of epilepsy and accounts for up to 10 percent of all cases of childhood epilepsy). Children with Lennox-Gastaut Syndrome experience delays in their development and may have up to dozens of different and mixed types of seizures a day. The most common types of seizures in Lennox-Gastaut syndrome are tonic (stiffening of the body, with the eyes rolling upwards, dilation of the pupils and shallow, irregular breathing), atonic (brief loss of muscle tone and consciousness, causing abrupt falls), myoclonic (sudden muscle jerks), and absence (staring spells with no muscle jerks).
Direction of use of Topamax
Generally Topamax is started with low doses (25 or 50 mg per day) and then increased slowly under guidance of a doctor (approximately 25 to 50 mg per week) until an effective daily dose is reached. This slow approach to treatment reduces side effects of Topamax.
In children, the starting dose is generally less than 25 mg (1 to 3 mg/kg/day), taken at night for the first week. The dose is then increased at 1 or 2 week intervals by 1 to 3 mg/kg/day. In children, the usual maintenance dose is 2.5 to 4.5 mg/kg twice daily.
The usual adult maintenance dose is 200 mg twice daily, but some adult patients may begin to see a clinical response at 200 mg per day. Some patients need doses higher than 200 mg daily. Patients should maintain an adequate fluid intake in order to minimize the risk of kidney stones.
If You Miss a Dose of Topamax
If you miss a dose of Topamax, you should take it as soon as you can remember. If it is almost time for the next dose you should skip the missed dose and go back to your regular schedule. Do not take more than required dose without consulting your doctor.
How to Store Topamax
Topamax tablets should be stored at room temperature, 59 to 86 degrees F (15 to 30 degrees C). Sprinkle capsules should be stored at or below 77 degrees F (25 degrees C). Do not store it in bathroom. Store it away from moisture, heat and light. Keep Topamax out of reach of children.
More Information About Topamax
Laboratory and or medical tests like regular eye examinations should be performed to monitor your progress. Do not share it with others for whom it was not prescribed. Do not use this medicine for other health conditions. If using this medicine for an extended period of time, obtain refills before your supply runs out. It may take few weeks for the benefits to be seen and you should not stop taking Topamax if you do not see any improvement after taking for few days. Keep taking Topamax even if you are feeling well, because if you stop it you may get attacks of epilepsy again.
Precautions to be Taken While Taking Topamax
- Acetazolamide (Diamox), dorzolamide (Trusopt), methazolamide (Neptazane), dichlorphenamide (Daranide) etc. if taken along with Topamax may increase the risk of kidney stones.
- Do not take Topamax if you have had an allergic reaction to it or are allergic to any of the ingredients used in this product.
- Carbamazepine and phenytoin may markedly decrease the amount of Topamax in the body by eliminating it faster from the body and as a result, Topamax not be effective unless doses are increased, which may increase side effects of Topamax.
- Topamax may decrease the amount of estrogen in the body of women, particularly if they are taking oral contraceptives. This may be responsible for increasing the chances of unwanted pregnancy.
- Patients with seizure disorders and on anticonvulsant medications, including Topamax, may develop nerve toxicity from a chemical, 4'-O-methylpyridoxine, found as a contaminant in some ginkgo preparations (an herbal medicine preparation used for increasing vitality).
- Do not stop using Topamax without consulting your doctor. Some medical conditions may become worse when Topamax is suddenly stopped including seizures of epilepsy.
- Keep all doctor and laboratory appointments while you are using this medicine. Laboratory and/or medical tests like measuring bicarbonate levels in your blood may be done, before you start taking this medicine and during therapy to monitor for side effects.
- Before you have to undergo any medical or dental treatment, emergency care, or surgery, you should inform your doctor or dentist that you are taking this medicine.
- Topamax can cause dizziness and drowsiness and some medicines and alcohol can cause additive action of these effects (dizziness and drowsiness) of Topamax. You should not drive, operate heavy machinery, or do anything else that could be dangerous and require constant attention and monitoring, until you know how you react to this medicine. Using this medicine alone, with other medicines, or with alcohol may lessen your ability to drive or to perform other potentially dangerous tasks.
- Topamax may reduce sweating which may be responsible for rise of your body temperature, especially in children, very old and weak people. The risk of rise of body temperature is greater in hot weather (as well as humid) and/or during vigorous exercise. You should drink plenty of fluids and dress lightly while in hot climates, or when exercising to prevent rise in body temperature. You should be careful for signs of decreased sweating and if you notice any, promptly seek cooler or air-conditioned shelter and/or stop exercising.
- Get immediate medical attention if your body temperature is above normal, or if you have mental or mood changes, headache, or dizziness during treatment with Topamax. Consult your doctor if you have any question.
- Before you begin taking any new medicine (including another anti epileptic medicine), either prescription or over-the-counter, check with your doctor or other health care provider.
- For women, taking Topamax along with birth control pills may decrease the effectiveness of your birth control pills and lead to unwanted pregnancy. To prevent pregnancy, use an additional form of birth control (like barrier method condom) while you are taking this medicine. Ask your doctor or pharmacist if you need more information.
- If you want to have baby during treatment with Topamax, discuss with your doctor the benefits and risks of using this medicine during pregnancy. It is not known clearly if this medicine is excreted in breast milk. If you are or will be breast-feeding while you are using this medicine, check with your doctor or pharmacist to discuss the risks to your baby.
Possible Adverse Effects of Topamax
- In adults, the most common and less serious side effects of Topamax are tiredness, dizziness, problems of coordination, speech problems, changes in vision like double vision (diplopia), difficulty with memory, and sensory distortion etc. In children, the most common side effects are drowsiness, tiredness, loss of appetite, nervousness, difficulty with concentration and attention, weight loss, aggressive reaction to minor things and difficulty with memory. If any of these minor side effects become bothersome and persistent you should consult your doctor.
- Eye examination (myopia or nearsightedness, redness, decreased depth of the anterior chamber of the eye and elevated ocular pressure etc. may be some of serious eye side effects) with or without dilation of the pupils should be done while taking Topamax. Fluid accumulation within the eye may displace the lens and iris anteriorly causing secondary angle closure glaucoma. If patients develop this syndrome, the treatment is to discontinue Topamax as rapidly as possible, according to the judgment of the treating physician. There have been few reports of sudden onset of vision and eye problems while taking Topamax, since topamax was approved by FDA.