Many medications can cause side effects. A side effect is an unwanted response to a medication when it is taken in normal doses. Side effects can be mild or severe, temporary or permanent.

The side effects listed below are not experienced by everyone who takes Topamax (Topiramate). If you are concerned about side effects, discuss the risks and benefits of Topamax (Topiramate) with your doctor.

The following side effects have been reported by at least 1% of people taking Topamax (Topiramate). Many of these side effects can be managed, and some may go away on their own over time.

Contact your doctor if you experience these side effects and they are severe or bothersome. Your pharmacist may be able to advise you on managing side effects.

• altered taste
• Constipation
• decreased appetite
• dizziness
• drowsiness
• fatigue
• headache
• nausea

Although most of the side effects listed below don't happen very often, they could lead to serious problems if you do not seek medical attention.

Check with your doctor as soon as possible if any of the following side effects occur:

• aggressive behaviour
• agitation
• burning or tingling sensations
• confusion
• coordination problems
• difficulty concentrating or slow thinking
• memory problems
• mood swings
• nervousness
• signs of Depression (e.g., poor concentration, changes in weight, changes in sleep, decreased interest in activities, thoughts of suicide)
• signs of high blood ammonia (e.g., decreased alertness, tiredness, vomiting)
• signs of Kidney Stones (e.g., flank pain, blood in urine, pain in lower back)
• signs of metabolic acidosis (e.g., unexplained tiredness, loss of appetite, decreased consciousness)
• speech disorders (e.g., hesitancy or word-finding difficulty)
• unexplained tiredness, vomiting, or confusion
• more frequent upper respiratory tract infections (e.g., colds, Bronchitis)
• weight loss

Stop taking the medication and seek immediate medical attention if any of the following occur:

• decreased sweating and increased body temperature
• signs of a serious allergic reaction (e.g., abdominal cramps, difficulty breathing, nausea and vomiting, or swelling of the face and throat)
• signs of severe skin reactions (e.g., blistering, peeling, a rash covering a large area of the body, a rash that spreads quickly, or a rash combined with Fever or discomfort)
• sudden vision change (e.g., blurred vision, painful red eyes, vision loss)
• thoughts of self-harm or suicide

Some people may experience side effects other than those listed. Check with your doctor if you notice any symptom that worries you while you are taking Topamax (Topiramate).

Tablets

25 mg
Each white, embossed, round, coated tablet, marked "TOP" on one side and "25" on the other, contains 25 mg of Topamax (Topiramate). Nonmedicinal ingredients: carnauba wax, hypromellose, lactose monohydrate, magnesium stearate, pregelatinized starch, microcrystalline cellulose, polyethylene glycol, polysorbate 80, purified water, sodium starch glycolate, and titanium dioxide; may contain synthetic iron oxide.

100 mg
Each yellow, embossed, round, coated tablet, marked "TOP" on one side and "100" on the other, contains 100 mg of Topamax (Topiramate). Nonmedicinal ingredients: carnauba wax, hypromellose, lactose monohydrate, magnesium stearate, pregelatinized starch, microcrystalline cellulose, polyethylene glycol, polysorbate 80, purified water, sodium starch glycolate, and titanium dioxide; may contain synthetic iron oxide.

200 mg
Each salmon, embossed, round, coated tablet, marked "TOP" on one side and "200" on the other, contains 200 mg of Topamax (Topiramate). Nonmedicinal ingredients: carnauba wax, hypromellose, lactose monohydrate, magnesium stearate, pregelatinized starch, microcrystalline cellulose, polyethylene glycol, polysorbate 80, purified water, sodium starch glycolate, and titanium dioxide; may contain synthetic iron oxide.

Sprinkle Capsules

15 mg
Each white, clear gelatin capsule, containing small white-to-off-white spheres, marked "TOP" and "15 mg" on the side, contains 15 mg of topiramate-coated beads. Nonmedicinal ingredients: black pharmaceutical ink, cellulose acetate, gelatin, povidone, sorbitan monolaurate, sodium lauryl sulfate, sugar spheres (sucrose and starch), and titanium dioxide.

25 mg
Each white, clear gelatin capsule, containing small white-to-off-white spheres, marked "TOP" and "25 mg" on the side, contains 25 mg of topiramate-coated beads. Nonmedicinal ingredients: black pharmaceutical ink, cellulose acetate, gelatin, povidone, sorbitan monolaurate, sodium lauryl sulfate, sugar spheres (sucrose and starch), and titanium dioxide.

Do not take Topamax (Topiramate) if you:

• are allergic to Topamax (Topiramate) or any ingredients of the medication

If you are taking Topamax (Topiramate) to prevent migraines, do not take Topamax (Topiramate) if you:

• are pregnant
• may become pregnant and are not using effective birth control.

Do not give Topamax (Topiramate) to children under 2 years of age.

There may be an interaction between Topamax (Topiramate) and any of the following:

• Acetazolamide
• acetylsalicylic acid (Asa)
• aclidinium
• alcohol
• amphetamines (e.g., Dextroamphetamine, Lisdexamfetamine)
• antihistamines (e.g., Diphenhydramine, Hydroxyzine, Loratadine)
• antipsychotics (e.g., Chlorpromazine, Clozapine, Haloperidol, Olanzapine, Quetiapine, Risperidone)
• antiseizure medications (e.g., Clobazam,  Levetiracetam, Phenobarbital, Phenytoin, primidone, Topamax (Topiramate), Valproic acid, zonisamide)
• atropine
• azelastine
• barbiturates (e.g., butalbital, pentobarbital, phenobarbital)
• benzodiazepines (e.g., Clonazepam, Diazepam, Lorazepam)
• Benztropine
• brimonidine
• Brinzolamide
• Buprenorphine
• Butorphanol
• cannabis
• chloral hydrate
• clidinium
• Clonidine
• Darifenacin
• Digoxin
• Disopyramide
• diuretics (water pills; e.g., Furosemide, Hydrochlorothiazide, triamterene)
• Dorzolamide
• Entacapone
• estrogens (e.g., ethinyl Estradiol)
• Flavoxate
• Flecainide
• glycopyrrolate
• ipratropium
• kava kava
• lithium
• Mefloquine
• Memantine
• Metformin
• Metoclopramide
• Mirtazapine
• muscle relaxants (e.g., Baclofen, Cyclobenzaprine, orphenadrine)
• Nabilone
• narcotic pain relievers (e.g., Codeine, Fentanyl, Hydromorphone, Morphine)
• oral contraceptives (birth control pills)
• Orlistat
• Oxybutynin
• Pioglitazone
• Pramipexole
• Pregabalin
• progestins (e.g., Levonorgestrel)
• Pseudoephedrine
• quinidine
• Ropinirole
• Rotigotine
• scopolamine
• Solifenacin
• suvorexant
• Tapentadol
• thalidomide
• tiotropium
• Tolterodine
• tricyclic antidepressants (e.g., Amitriptyline, Clomipramine, Desipramine, Trimipramine)
• Ulipristal
• umeclidinium
• Zolpidem
• Zopiclone

If you are taking any of these medications, speak with your doctor or pharmacist. Depending on your specific circumstances, your doctor may want you to:

• stop taking one of the medications,
• change one of the medications to another,
• change how you are taking one or both of the medications, or
• leave everything as is.

An interaction between two medications does not always mean that you must stop taking one of them. Speak to your doctor about how any drug interactions are being managed or should be managed.

Medications other than those listed above may interact with Topamax (Topiramate). Tell your doctor or prescriber about all prescription, over-the-counter (non-prescription), and herbal medications you are taking. Also tell them about any supplements you take. Since caffeine, alcohol, the Nicotine from cigarettes, or street drugs can affect the action of many medications, you should let your prescriber know if you use them.

Before you begin using a medication, be sure to inform your doctor of any medical conditions or Allergies you may have, any medications you are taking, whether you are pregnant or breast-feeding, and any other significant facts about your health. These factors may affect how you should use Topamax (Topiramate).

Ammonia: Topamax (Topiramate) may cause elevated levels of ammonia in the blood, which can cause changes in mental alertness. If you have symptoms of decreased alertness, confusion, tiredness, vomiting, or a low body temperature (less than 35°C), contact your doctor immediately.

Birth control: Topamax (Topiramate) has been shown to affect birth control pills that contain low doses of estrogen. If you are taking birth control pills, your pill should contain no less than 30 µg of estrogen. Report any changes in bleeding patterns to your doctor.

Depression: Topamax (Topiramate) may contribute to mood swings and symptoms of depression. If you have depression or a history of depression, discuss with your doctor how Topamax (Topiramate) may affect your medical condition, how your medical condition may affect the dosing and effectiveness of Topamax (Topiramate), and whether any special monitoring is needed. If you experience symptoms of depression such as poor concentration, changes in weight, changes in sleep, decreased interest in activities, or notice them in a family member who is taking Topamax (Topiramate), contact your doctor as soon as possible.

Drowsiness/reduced alertness: Topamax (Topiramate) can cause difficulty with concentration, speech or language problems, and drowsiness or fatigue. If you are taking Topamax (Topiramate) you should not drive or operate machinery until you have had a chance to see if it affects your mental or physical performance.

Heat regulation: For some people, especially children, Topamax (Topiramate) may cause decreased sweating and increased body temperature. Let your doctor know if you or a child taking Topamax (Topiramate) experiences these symptoms. You should make sure you are properly hydrating during exposure to warm temperatures, as well as before and during exercise.

Kidney function: Kidney Disease or reduced kidney function may cause Topamax (Topiramate) to build up in the body, causing side effects. If you have reduced kidney function or kidney disease, discuss with your doctor how Topamax (Topiramate) may affect your medical condition, how your medical condition may affect the dosing and effectiveness of Topamax (Topiramate), and whether any special monitoring is needed.

Kidney stones: Approximately 2% of people taking Topamax (Topiramate) develop kidney stones. Men seem to be at greater risk for this. Be sure to drink plenty of fluids while taking Topamax (Topiramate) in order to reduce the risk of kidney stone formation. If you experience pain in the kidney or flank areas, contact your doctor to have this investigated.

Laboratory tests: Topamax (Topiramate) may decrease sodium bicarbonate levels and lead to metabolic acidosis. If you experience shallow, rapid breathing, unusual tiredness and loss of appetite, contact your doctor. Sodium bicarbonate levels should be monitored by your doctor with blood tests, while you are taking Topamax (Topiramate).

Liver function: Liver disease or reduced liver function may cause Topamax (Topiramate) to build up in the body, causing side effects. If you have liver problems, discuss with your doctor how Topamax (Topiramate) may affect your medical condition, how your medical condition may affect the dosing and effectiveness of Topamax (Topiramate), and whether any special monitoring is needed. Your doctor may want to test your liver function regularly with blood tests while you are taking Topamax (Topiramate).

Suicidal or agitated behaviour: People taking Topamax (Topiramate) may feel agitated (restless, anxious, aggressive, emotional, and feeling not like themselves), or they may want to hurt themselves or others. These symptoms may occur within several weeks after starting Topamax (Topiramate). If you experience these side effects or notice them in a family member who is taking Topamax (Topiramate), contact your doctor immediately. You should be closely monitored by your doctor for emotional and behaviour changes while taking Topamax (Topiramate).

Stopping treatment: If you are taking Topamax (Topiramate) to control seizures, it should be stopped gradually to decrease the risk of seizures. If it is necessary to stop taking Topamax (Topiramate), discuss with your doctor the best way to reduce your dose gradually. Do not stop taking Topamax (Topiramate) without talking to your doctor.

Vision changes: Topamax (Topiramate) may cause the symptoms of Glaucoma (increased pressure in the eye) to become worse. If you have glaucoma, discuss with your doctor how Topamax (Topiramate) may affect your medical condition, how your medical condition may affect the dosing and effectiveness of Topamax (Topiramate), and whether any special monitoring is needed. If you are taking Topamax (Topiramate) you should immediately report blurred vision or painful and red eyes to a doctor. If left untreated, these symptoms can lead to permanent vision loss.

Pregnancy: Topamax (Topiramate) may cause harm to the developing baby if it is taken by a woman while she is pregnant. Topamax (Topiramate) should not be used during pregnancy unless the benefits outweigh the risks. If you become pregnant while taking Topamax (Topiramate), contact your doctor immediately.

Breast-feeding: Topamax (Topiramate) may pass into breast milk. If you are breast-feeding and taking Topamax (Topiramate), it may affect your baby. Talk to your doctor about whether you should continue breast-feeding.

Children and adolescents: Topamax (Topiramate) can be used in children aged 2 and older for seizures. The safety and effectiveness of using Topamax (Topiramate) have not been established for children under the age of 2. The safety and effectiveness of using Topamax (Topiramate) to prevent migraine headaches has not been established for children less than 18 years of age.