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Topamax is an anticonvulsant drug, prescribed for patients with epilepsy; however, it is also approved by the FDA for migraine prevention treatment.
It has also been used to treat bipolar disorder and to counteract the effects of antidepressant medications. Unfortunately, there might be some harmful Topamax side effects, such as the following:
- Memory Loss
- Upper Respitory Tract Infection
- Suicidal ideation, tendencies, attempts
Ortho-McNeil, the former producer of Topamax, has been fined $6.14 million for promoting Topamax for use as treatment for non-FDA approved psychiatric disorders.
While doctors are technically allowed to prescribe Topamax for any ailment, producers of drugs are not allowed to market the drug in such a way. In any case, there is no conclusive evidence that Topamax is a useful or effective treatment for most psychiatric disorders.
If you or your loved ones have experienced any serious complications as a result of Topamax (see below), or if you believe that a ill-informed prescription has been made, contact our attorneys today for a free consultation to discuss your legal options.
HIGHLIGHTS OF PRESCRIBING INFORMATION
These highlights do not include all the information needed to use TOPAMAX safely and effectively. See full prescribing information for TOPAMAX
TOPAMAX (topiramate) TABLETS, for oral use
TOPAMAX (topiramate capsules) SPRINKLE CAPSULES, for oral use Initial U.S. Approval: 1996
WARNINGS AND PRECAUTIONS
Acute myopia and secondary angle closure glaucoma: can lead to permanent visual loss; discontinue TOPAMAX as soon as possible (5.1)
Visual field defects: consider discontinuation of TOPAMAX (5.2)
Oligohidrosis and hyperthermia: monitor decreased sweating and increased body temperature, especially in pediatric patients (5.3)
Metabolic acidosis: baseline and periodic measurement of serum bicarbonate is recommended; consider dose reduction or discontinuation of TOPAMAX if clinically appropriate (5.4)
Suicidal behavior and ideation: antiepileptic drugs increase the risk of suicidal behavior or ideation (5.5)
Cognitive/neuropsychiatric adverse reactions: use caution when operating machinery including cars; depression and mood problems may occur (5.6)
Fetal Toxicity: use during pregnancy can cause cleft lip and/or palate and being small for gestational age (5.7)
Withdrawal of AEDs: withdraw TOPAMAX gradually (5.8)
Hyperammonemia/encephalopathy: measure ammonia if encephalopathic symptoms occur (5.9)
Kidney stones: avoid use with other carbonic anhydrase inhibitors, drugs causing metabolic acidosis, or in patients on a ketogenic diet (5.10)
Hypothermia has been reported with and without hyperammonemia during topiramate treatment with concomitant valproic acid use (5.11)
Epilepsy: Most common (≥10% more frequent than placebo or low-dose TOPAMAX) adverse reactions in adult and pediatric patients were: paresthesia, anorexia, weight loss, speech disorders/related speech problems, fatigue, dizziness, somnolence, nervousness, psychomotor slowing, abnormal vision and fever (6.1)
Migraine: Most common (≥5% more frequent than placebo) adverse reactions in adult and pediatric patients were: paresthesia, anorexia, weight loss, difficulty with memory, taste perversion, diarrhea, hypoesthesia, nausea, abdominal pain and upper respiratory tract infection (6.1)
6 ADVERSE REACTIONS
The following serious adverse reactions are discussed in more detail in other sections of the labeling:
Acute Myopia and Secondary Angle Closure Glaucoma [see Warnings and Precautions (5.1)]
Visual Field Defects [see Warnings and Precautions (5.2)]
Oligohidrosis and Hyperthermia [see Warnings and Precautions (5.3)]
Metabolic Acidosis [see Warnings and Precautions (5.4)]
Suicidal Behavior and Ideation [see Warnings and Precautions (5.5)]
Cognitive/Neuropsychiatric Adverse Reactions [see Warnings and Precautions (5.6)]
Hyperammonemia and Encephalopathy (Without and With Concomitant Valproic Acid [VPA] Use) [see Warnings and Precautions (5.9)]
Kidney Stones [see Warnings and Precautions (5.10)]
Hypothermia with Concomitant Valproic Acid (VPA) Use [see Warnings and Precautions (5.11)]
TOPAMAX- topiramate tablet, coated
- 5 WARNINGS AND PRECAUTIONS
5.1 Acute Myopia and Secondary Angle Closure Glaucoma
A syndrome consisting of acute myopia associated with secondary angle closure glaucoma has been reported in patients receiving TOPAMAX® (topiramate). Symptoms include acute onset of decreased visual acuity and/or ocular pain. Ophthalmologic findings can include myopia, anterior chamber shallowing, ocular hyperemia (redness), and increased intraocular pressure. Mydriasis may or may not be present. This syndrome may be associated with supraciliary effusion resulting in anterior displacement of the lens and iris, with secondary angle closure glaucoma. Symptoms typically occur within 1 month of initiating TOPAMAX® therapy. In contrast to primary narrow angle glaucoma, which is rare under 40 years of age, secondary angle closure glaucoma associated with topiramate has been reported in pediatric patients as well as adults. The primary treatment to reverse symptoms is discontinuation of TOPAMAX® as rapidly as possible, according to the judgment of the treating physician. Other measures, in conjunction with discontinuation of TOPAMAX®, may be helpful.
Elevated intraocular pressure of any etiology, if left untreated, can lead to serious sequelae including permanent vision loss.
5.2 Oligohidrosis and Hyperthermia
Oligohidrosis (decreased sweating), infrequently resulting in hospitalization, has been reported in association with TOPAMAX® use. Decreased sweating and an elevation in body temperature above normal characterized these cases. Some of the cases were reported after exposure to elevated environmental temperatures.
The majority of the reports have been in pediatric patients. Patients, especially pediatric patients, treated with TOPAMAX® should be monitored closely for evidence of decreased sweating and increased body temperature, especially in hot weather. Caution should be used when TOPAMAX® is prescribed with other drugs that predispose patients to heat-related disorders; these drugs include, but are not limited to, other carbonic anhydrase inhibitors and drugs with anticholinergic activity.
5.3 Metabolic Acidosis
Hyperchloremic, non-anion gap, metabolic acidosis (i.e., decreased serum bicarbonate below the normal reference range in the absence of chronic respiratory alkalosis) is associated with TOPAMAX® treatment. This metabolic acidosis is caused by renal bicarbonate loss due to the inhibitory effect of topiramate on carbonic anhydrase. Such electrolyte imbalance has been observed with the use of topiramate in placebo-controlled clinical trials and in the post-marketing period. Generally, topiramate-induced metabolic acidosis occurs early in treatment although cases can occur at any time during treatment. Bicarbonate decrements are usually mild-moderate (average decrease of 4 mEq/L at daily doses of 400 mg in adults and at approximately 6 mg/kg/day in pediatric patients); rarely, patients can experience severe decrements to values below 10 mEq/L. Conditions or therapies that predispose patients to acidosis (such as renal disease, severe respiratory disorders, status epilepticus, diarrhea, ketogenic diet, or specific drugs) may be additive to the bicarbonate lowering effects of topiramate.
In adults, the incidence of persistent treatment-emergent decreases in serum bicarbonate (levels of <20 mEq/L at two consecutive visits or at the final visit) in controlled clinical trials for adjunctive treatment of epilepsy was 32% for 400 mg/day, and 1% for placebo. Metabolic acidosis has been observed at doses as low as 50 mg/day. The incidence of persistent treatment-emergent decreases in serum bicarbonate in adults in the epilepsy controlled clinical trial for monotherapy was 15% for 50 mg/day and 25% for 400 mg/day. The incidence of a markedly abnormally low serum bicarbonate (i.e., absolute value <17 mEq/L and >5 mEq/L decrease from pretreatment) in the adjunctive therapy trials was 3% for 400 mg/day, and 0% for placebo and in the monotherapy trial was 1% for 50 mg/day and 7% for 400 mg/day. Serum bicarbonate levels have not been systematically evaluated at daily doses greater than 400 mg/day.
In pediatric patients (2 to 16 years of age), the incidence of persistent treatment-emergent decreases in serum bicarbonate in placebo-controlled trials for adjunctive treatment of Lennox-Gastaut syndrome or refractory partial onset seizures was 67% for TOPAMAX® (at approximately 6 mg/kg/day), and 10% for placebo. The incidence of a markedly abnormally low serum bicarbonate (i.e., absolute value <17 mEq/L and >5 mEq/L decrease from pretreatment) in these trials was 11% for TOPAMAX® and 0% for placebo. Cases of moderately severe metabolic acidosis have been reported in patients as young as 5 months old, especially at daily doses above 5 mg/kg/day.
Measurement of baseline and periodic serum bicarbonate during topiramate treatment is recommended. If metabolic acidosis develops and persists, consideration should be given to reducing the dose or discontinuing topiramate (using dose tapering). If the decision is made to continue patients on topiramate in the face of persistent acidosis, alkali treatment should be considered.
5.4 Suicidal Behavior and Ideation
Antiepileptic drugs (AEDs), including TOPAMAX®, increase the risk of suicidal thoughts or behavior in patients taking these drugs for any indication. Patients treated with any AED for any indication should be monitored for the emergence or worsening of depression, suicidal thoughts or behavior, and/or any unusual changes in mood or behavior.
Pooled analyses of 199 placebo-controlled clinical trials (mono- and adjunctive therapy) of 11 different AEDs showed that patients randomized to one of the AEDs had approximately twice the risk (adjusted Relative Risk 1.8, 95% CI:1.2, 2.7) of suicidal thinking or behavior compared to patients randomized to placebo. In these trials, which had a median treatment duration of 12 weeks, the estimated incidence rate of suicidal behavior or ideation among 27,863 AED-treated patients was 0.43%, compared to 0.24% among 16,029 placebo-treated patients, representing an increase of approximately one case of suicidal thinking or behavior for every 530 patients treated. There were four suicides in drug-treated patients in the trials and none in placebo-treated patients, but the number is too small to allow any conclusion about drug effect on suicide.
The increased risk of suicidal thoughts or behavior with AEDs was observed as early as one week after starting drug treatment with AEDs and persisted for the duration of treatment assessed. Because most trials included in the analysis did not extend beyond 24 weeks, the risk of suicidal thoughts or behavior beyond 24 weeks could not be assessed.
The risk of suicidal thoughts or behavior was generally consistent among drugs in the data analyzed. The finding of increased risk with AEDs of varying mechanisms of action and across a range of indications suggests that the risk applies to all AEDs used for any indication. The risk did not vary substantially by age (5 to 100 years) in the clinical trials analyzed.
Table 4 shows absolute and relative risk by indication for all evaluated AEDs.
Table 4: Risk by Indication for Antiepileptic Drugs in the Pooled Analysis Indication Placebo Patients with Events per 1000 Patients Drug Patients with Events per 1000 Patients Relative Risk: Incidence of Events in Drug Patients/Incidence in Placebo Patients Risk Difference: Additional Drug Patients with Events per 1000 Patients Epilepsy 1.0 3.4 3.5 2.4 Psychiatric 5.7 8.5 1.5 2.9 Other 1.0 1.8 1.9 0.9 Total 2.4 4.3 1.8 1.9
The relative risk for suicidal thoughts or behavior was higher in clinical trials for epilepsy than in clinical trials for psychiatric or other conditions, but the absolute risk differences were similar for the epilepsy and psychiatric indications.
Anyone considering prescribing TOPAMAX® or any other AED must balance the risk of suicidal thoughts or behavior with the risk of untreated illness. Epilepsy and many other illnesses for which AEDs are prescribed are themselves associated with morbidity and mortality and an increased risk of suicidal thoughts and behavior. Should suicidal thoughts and behavior emerge during treatment, the prescriber needs to consider whether the emergence of these symptoms in any given patient may be related to the illness being treated.
Patients, their caregivers, and families should be informed that AEDs increase the risk of suicidal thoughts and behavior and should be advised of the need to be alert for the emergence or worsening of the signs and symptoms of depression, any unusual changes in mood or behavior or the emergence of suicidal thoughts, or behavior or thoughts about self-harm. Behaviors of concern should be reported immediately to healthcare providers.
5.5 Cognitive/Neuropsychiatric Adverse Reactions
Adverse reactions most often associated with the use of TOPAMAX® were related to the central nervous system and were observed in both the epilepsy and migraine populations. In adults, the most frequent of these can be classified into three general categories: 1) Cognitive-related dysfunction (e.g., confusion, psychomotor slowing, difficulty with concentration/attention, difficulty with memory, speech or language problems, particularly word-finding difficulties); 2) Psychiatric/behavioral disturbances (e.g., depression or mood problems); and 3) Somnolence or fatigue.
The majority of cognitive-related adverse reactions were mild to moderate in severity, and they frequently occurred in isolation. Rapid titration rate and higher initial dose were associated with higher incidences of these reactions. Many of these reactions contributed to withdrawal from treatment [see Adverse Reactions (6)].
In the add-on epilepsy controlled trials (using rapid titration such as 100–200 mg/day weekly increments), the proportion of patients who experienced one or more cognitive-related adverse reactions was 42% for 200 mg/day, 41% for 400 mg/day, 52% for 600 mg/day, 56% for 800 and 1,000 mg/day, and 14% for placebo. These dose-related adverse reactions began with a similar frequency in the titration or in the maintenance phase, although in some patients the events began during titration and persisted into the maintenance phase. Some patients who experienced one or more cognitive-related adverse reactions in the titration phase had a dose-related recurrence of these reactions in the maintenance phase.
In the monotherapy epilepsy controlled trial, the proportion of patients who experienced one or more cognitive-related adverse reactions was 19% for TOPAMAX® 50 mg/day and 26% for 400 mg/day.
In the 6-month migraine prophylaxis controlled trials using a slower titration regimen (25 mg/day weekly increments), the proportion of patients who experienced one or more cognitive-related adverse reactions was 19% for TOPAMAX® 50 mg/day, 22% for 100 mg/day (the recommended dose), 28% for 200 mg/day, and 10% for placebo. These dose-related adverse reactions typically began in the titration phase and often persisted into the maintenance phase, but infrequently began in the maintenance phase. Some patients experienced a recurrence of one or more of these cognitive adverse reactions and this recurrence was typically in the titration phase. A relatively small proportion of topiramate-treated patients experienced more than one concurrent cognitive adverse reaction. The most common cognitive adverse reactions occurring together included difficulty with memory along with difficulty with concentration/attention, difficulty with memory along with language problems, and difficulty with concentration/attention along with language problems. Rarely, topiramate-treated patients experienced three concurrent cognitive reactions.
Psychiatric/behavioral disturbances (depression or mood) were dose-related for both the epilepsy and migraine populations [see Warnings and Precautions (5.4)].
Somnolence and fatigue were the adverse reactions most frequently reported during clinical trials of TOPAMAX® for adjunctive epilepsy. For the adjunctive epilepsy population, the incidence of somnolence did not differ substantially between 200 mg/day and 1,000 mg/day, but the incidence of fatigue was dose-related and increased at dosages above 400 mg/day. For the monotherapy epilepsy population in the 50 mg/day and 400 mg/day groups, the incidence of somnolence was dose-related (9% for the 50 mg/day group and 15% for the 400 mg/day group) and the incidence of fatigue was comparable in both treatment groups (14% each). For the migraine population, fatigue and somnolence were dose-related and more common in the titration phase.
Additional nonspecific CNS events commonly observed with topiramate in the add-on epilepsy population included dizziness or ataxia.
In double-blind adjunctive therapy and monotherapy epilepsy clinical studies, the incidences of cognitive/neuropsychiatric adverse reactions in pediatric patients were generally lower than observed in adults. These reactions included psychomotor slowing, difficulty with concentration/attention, speech disorders/related speech problems, and language problems. The most frequently reported neuropsychiatric reactions in pediatric patients during adjunctive therapy double-blind studies were somnolence and fatigue. The most frequently reported neuropsychiatric reactions in pediatric patients in the 50 mg/day and 400 mg/day groups during the monotherapy double-blind study were headache, dizziness, anorexia, and somnolence.
No patients discontinued treatment due to any adverse reactions in the adjunctive epilepsy double-blind trials. In the monotherapy epilepsy double-blind trial, 1 pediatric patient (2%) in the 50 mg/day group and 7 pediatric patients (12%) in the 400 mg/day group discontinued treatment due to any adverse reactions. The most common adverse reaction associated with discontinuation of therapy was difficulty with concentration/attention; all occurred in the 400 mg/day group.
5.6 Fetal Toxicity
TOPAMAX® can cause fetal harm when administered to a pregnant woman. Data from pregnancy registries indicate that infants exposed to topiramate in utero have an increased risk for cleft lip and/or cleft palate (oral clefts). When multiple species of pregnant animals received topiramate at clinically relevant doses, structural malformations, including craniofacial defects, and reduced fetal weights occurred in offspring [see Use in Specific Populations (8.1)].
Consider the benefits and the risks of TOPAMAX® when administering this drug in women of childbearing potential, particularly when TOPAMAX® is considered for a condition not usually associated with permanent injury or death [see Use in Specific Populations (8.9) and Patient Counseling Information (17.8)]. TOPAMAX® should be used during pregnancy only if the potential benefit outweighs the potential risk. If this drug is used during pregnancy, or if the patient becomes pregnant while taking this drug, the patient should be apprised of the potential hazard to a fetus [see Use in Specific Populations (8.1) and (8.9)].
5.7 Withdrawal of Antiepileptic Drugs (AEDs)
In patients with or without a history of seizures or epilepsy, antiepileptic drugs, including TOPAMAX®, should be gradually withdrawn to minimize the potential for seizures or increased seizure frequency [see Clinical Studies (14)]. In situations where rapid withdrawal of TOPAMAX® is medically required, appropriate monitoring is recommended.
5.8 Sudden Unexplained Death in Epilepsy (SUDEP)
During the course of premarketing development of topiramate tablets, 10 sudden and unexplained deaths were recorded among a cohort of treated patients (2796 subject years of exposure). This represents an incidence of 0.0035 deaths per patient year. Although this rate exceeds that expected in a healthy population matched for age and sex, it is within the range of estimates for the incidence of sudden unexplained deaths in patients with epilepsy not receiving TOPAMAX® (ranging from 0.0005 for the general population of patients with epilepsy, to 0.003 for a clinical trial population similar to that in the TOPAMAX® program, to 0.005 for patients with refractory epilepsy).
5.9 Hyperammonemia and Encephalopathy (Without and With Concomitant Valproic Acid [VPA] Use)
Hyperammonemia/Encephalopathy Without Concomitant Valproic Acid (VPA)
Topiramate treatment has produced hyperammonemia (in some instances dose-related) in clinical investigational programs of adolescents (12–16 years) who were treated with topiramate monotherapy for migraine prophylaxis (incidence above the upper limit of normal, 22% for placebo, 26% for 50 mg/day, 41% for 100 mg/day) and in very young pediatric patients (1–24 months) who were treated with adjunctive topiramate for partial onset epilepsy (8% for placebo, 10% for 5 mg/kg/day, 0% for 15 mg/kg/day, 9% for 25 mg/kg/day). TOPAMAX® is not approved as monotherapy for migraine prophylaxis in adolescent patients or as adjunctive treatment of partial onset seizures in pediatric patients less than 2 years old. In some patients, ammonia was markedly increased (≥50% above upper limit of normal). In adolescent patients, the incidence of markedly increased hyperammonemia was 6% for placebo, 6% for 50 mg, and 12% for 100 mg topiramate daily. The hyperammonemia associated with topiramate treatment occurred with and without encephalopathy in placebo-controlled trials and in an open-label, extension trial. Dose-related hyperammonemia was also observed in the extension trial in pediatric patients up to 2 years old. Clinical symptoms of hyperammonemic encephalopathy often include acute alterations in level of consciousness and/or cognitive function with lethargy or vomiting.
Hyperammonemia with and without encephalopathy has also been observed in post-marketing reports in patients who were taking topiramate without concomitant valproic acid (VPA).
Hyperammonemia/Encephalopathy With Concomitant Valproic Acid (VPA)
Concomitant administration of topiramate and valproic acid (VPA) has been associated with hyperammonemia with or without encephalopathy in patients who have tolerated either drug alone based upon post-marketing reports. Although hyperammonemia may be asymptomatic, clinical symptoms of hyperammonemic encephalopathy often include acute alterations in level of consciousness and/or cognitive function with lethargy or vomiting. In most cases, symptoms and signs abated with discontinuation of either drug. This adverse reaction is not due to a pharmacokinetic interaction.
Although TOPAMAX® is not indicated for use in infants/toddlers (1–24 months), VPA clearly produced a dose-related increase in the incidence of treatment-emergent hyperammonemia (above the upper limit of normal, 0% for placebo, 12% for 5 mg/kg/day, 7% for 15 mg/kg/day, 17% for 25 mg/kg/day) in an investigational program. Markedly increased, dose-related hyperammonemia (0% for placebo and 5 mg/kg/day, 7% for 15 mg/kg/day, 8% for 25 mg/kg/day) also occurred in these infants/toddlers. Dose-related hyperammonemia was similarly observed in a long-term extension trial in these very young, pediatric patients [see Use in Specific Populations (8.4)].
Hyperammonemia with and without encephalopathy has also been observed in post-marketing reports in patients taking topiramate with VPA.
The hyperammonemia associated with topiramate treatment appears to be more common when topiramate is used concomitantly with VPA.
Monitoring for Hyperammonemia
Patients with inborn errors of metabolism or reduced hepatic mitochondrial activity may be at an increased risk for hyperammonemia with or without encephalopathy. Although not studied, topiramate treatment or an interaction of concomitant topiramate and valproic acid treatment may exacerbate existing defects or unmask deficiencies in susceptible persons.
In patients who develop unexplained lethargy, vomiting, or changes in mental status associated with any topiramate treatment, hyperammonemic encephalopathy should be considered and an ammonia level should be measured.
5.10 Kidney Stones
A total of 32/2086 (1.5%) of adults exposed to topiramate during its adjunctive epilepsy therapy development reported the occurrence of kidney stones, an incidence about 2 to 4 times greater than expected in a similar, untreated population. In the double-blind monotherapy epilepsy study, a total of 4/319 (1.3%) of adults exposed to topiramate reported the occurrence of kidney stones. As in the general population, the incidence of stone formation among topiramate-treated patients was higher in men. Kidney stones have also been reported in pediatric patients. During long-term (up to 1 year) topiramate treatment in an open-label extension study of 284 pediatric patients 1–24 months old with epilepsy, 7% developed kidney or bladder stones that were diagnosed clinically or by sonogram. TOPAMAX® is not approved for pediatric patients less than 2 years old [see Use in Specific Populations (8.4)].
An explanation for the association of TOPAMAX® and kidney stones may lie in the fact that topiramate is a carbonic anhydrase inhibitor. Carbonic anhydrase inhibitors (e.g., zonisamide, acetazolamide, or dichlorphenamide) can promote stone formation by reducing urinary citrate excretion and by increasing urinary pH [see Warnings and Precautions (5.3)]. The concomitant use of TOPAMAX® with any other drug producing metabolic acidosis, or potentially in patients on a ketogenic diet, may create a physiological environment that increases the risk of kidney stone formation, and should therefore be avoided.
Increased fluid intake increases the urinary output, lowering the concentration of substances involved in stone formation. Hydration is recommended to reduce new stone formation.
Paresthesia (usually tingling of the extremities), an effect associated with the use of other carbonic anhydrase inhibitors, appears to be a common effect of TOPAMAX®. Paresthesia was more frequently reported in the monotherapy epilepsy trials and migraine prophylaxis trials than in the adjunctive therapy epilepsy trials. In the majority of instances, paresthesia did not lead to treatment discontinuation.
5.13 Adjustment of Dose in Renal Failure
The major route of elimination of unchanged topiramate and its metabolites is via the kidney. Dosage adjustment may be required in patients with reduced renal function [see Dosage and Administration (2.4)].
5.14 Decreased Hepatic Function
In hepatically impaired patients, TOPAMAX® should be administered with caution as the clearance of topiramate may be decreased [see Dosage and Administration (2.7)].
5.15 Monitoring: Laboratory Tests
Topiramate treatment was associated with changes in several clinical laboratory analytes in randomized, double-blind, placebo-controlled studies.
Topiramate treatment causes non-anion gap, hyperchloremic metabolic acidosis manifested by a decrease in serum bicarbonate and an increase in serum chloride. Measurement of baseline and periodic serum bicarbonate during TOPAMAX® treatment is recommended [see Warnings and Precautions (5.3)].
Controlled trials of adjunctive topiramate treatment of adults for partial onset seizures showed an increased incidence of markedly decreased serum phosphorus (6% topiramate, 2% placebo), markedly increased serum alkaline phosphatase (3% topiramate, 1% placebo), and decreased serum potassium (0.4 % topiramate, 0.1 % placebo). The clinical significance of these abnormalities has not been clearly established.
Changes in several clinical laboratory values (i.e., increased creatinine, BUN, alkaline phosphatase, total protein, total eosinophil count, and decreased potassium) have been observed in a clinical investigational program in very young (<2 years) pediatric patients who were treated with adjunctive topiramate for partial onset seizures [see Use in Specific Populations (8.4)].
Topiramate treatment produced a dose-related increased shift in serum creatinine from normal at baseline to an increased value at the end of 4 months treatment in adolescent patients (ages 12–16 years) who were treated for migraine prophylaxis in a double-blind, placebo-controlled study.
TOPAMAX® treatment with or without concomitant valproic acid (VPA) can cause hyperammonemia with or without encephalopathy [see Warnings and Precautions (5.9)].
- 6 ADVERSE REACTIONS
Because clinical trials are conducted under widely varying conditions, adverse reaction rates observed in the clinical trials of a drug cannot be directly compared to rates in the clinical trials of another drug and may not reflect the rates observed in practice.
The following adverse reactions are discussed in more detail in other sections of the labeling:
- Acute Myopia and Secondary Angle Closure [see Warnings and Precautions (5.1)]
- Oligohidrosis and Hyperthermia [see Warnings and Precautions (5.2)]
- Metabolic Acidosis [see Warnings and Precautions (5.3)]
- Suicidal Behavior and Ideation [see Warnings and Precautions (5.4)]
- Cognitive/Neuropsychiatric Adverse Reactions [see Warnings and Precautions (5.5)]
- Fetal Toxicity [see Warnings and Precautions (5.6) and Use in Specific Populations (8.1)]
- Withdrawal of Antiepileptic Drugs (AEDs) [see Warnings and Precautions (5.7)]
- Sudden Unexplained Death in Epilepsy (SUDEP) [see Warnings and Precautions (5.8)]
- Hyperammonemia and Encephalopathy (Without and With Concomitant Valproic Acid [VPA] Use [see Warnings and Precautions (5.9)]
- Kidney Stones [see Warnings and Precautions (5.10)]
- Hypothermia with Concomitant Valproic Acid (VPA) Use [see Warnings and Precautions (5.11)]
- Paresthesia [see Warnings and Precautions (5.12)]
The data described in the following sections were obtained using TOPAMAX® (topiramate) Tablets.
Welcome: What is TOPAMAX®?
TOPAMAX® is indicated for:
Adults and adolescents 12 years of age and older for the prophylaxis of migraine headache. The usefulness of TOPAMAX® in the acute treatment of migraine headache has not been studied.
Initial monotherapy in patients 2 years of age and older with partial onset or primary generalized tonic-clonic seizures. Safety and effectiveness in patients who were converted to monotherapy from a previous regimen of other anticonvulsant drugs have not been established in controlled trials.
Adjunctive therapy for adults and pediatric patients ages 2 to 16 years with partial onset seizures or primary generalized tonic-clonic seizures, and in patients 2 years of age and older with seizures associated with Lennox-Gastaut syndrome.
Important Safety Information
What is the most important information I should know about TOPAMAX®?
TOPAMAX® may cause eye problems. Serious eye problems include:
- Any sudden decrease in vision with or without eye pain and redness.
- A blockage of fluid in the eye causing increased pressure in the eye (secondary angle closure glaucoma).
These eye problems can lead to permanent loss of vision if not treated.
You should call your healthcare provider right away if you have any new eye symptoms, including any new problems with your vision.
TOPAMAX® may cause decreased sweating and increased body temperature (fever). People, especially children, should be watched for signs of decreased sweating and fever, especially in hot temperatures. Some people may need to be hospitalized for this condition. If a high fever, a fever that does not go away, or decreased sweating develops, call your healthcare provider right away.
TOPAMAX® can increase the level of acid in your blood (metabolic acidosis). If left untreated, metabolic acidosis can cause brittle or soft bones (osteoporosis, osteomalacia, osteopenia), kidney stones, can slow the rate of growth in children, and may possibly harm your baby if you are pregnant. Metabolic acidosis can happen with or without symptoms. Sometimes people with metabolic acidosis will:
- Feel tired
- Not feel hungry (loss of appetite)
- Feel changes in heartbeat
- Have trouble thinking clearly
Your healthcare provider should do a blood test to measure the level of acid in your blood before and during your treatment with TOPAMAX®. If you are pregnant, you should talk to your healthcare provider about whether you have metabolic acidosis.
Like other antiepileptic drugs, TOPAMAX® may cause suicidal thoughts or actions in a very small number of people, about 1 in 500. Call a healthcare provider right away if you have any of these symptoms, especially if they are new, worse, or worry you:
TOPAMAX® may lower bone mineral density. TOPAMAX® may decrease the density of bones when used over a long period.
TOPAMAX® may have negative effects on growth in children. TOPAMAX® may slow height increases and weight gain in children and adolescents when used over a long period
Do not stop TOPAMAX® without first talking to a healthcare provider.
- Stopping TOPAMAX® suddenly can cause serious problems.
- Suicidal thoughts or actions can be caused by things other than medicines. If you have suicidal thoughts or actions, your healthcare provider may check for other causes.
- If you have epilepsy and you stop taking TOPAMAX® suddenly, you may have seizures that do not stop. Your healthcare provider will tell you how to stop taking TOPAMAX® slowly.
- If you miss a single dose of TOPAMAX®, take it as soon as you can. However, if you are within 6 hours of taking your next scheduled dose, wait until then to take your usual dose of TOPAMAX® and skip the missed dose. Do not double your dose. If you have missed more than one dose, you should call your healthcare provider for advice.
How can I watch for early symptoms of suicidal thoughts and actions?
- Pay attention to any changes, especially sudden changes, in mood, behaviors, thoughts, or feelings.
- Keep all follow-up visits with your healthcare provider as scheduled.
- Call your healthcare provider between visits as needed, especially if you are worried about symptoms.
TOPAMAX® can harm your unborn baby.
- If you take TOPAMAX® during pregnancy, your baby has a higher risk for birth defects called cleft lip and cleft palate. These defects can begin early in pregnancy, even before you know you are pregnant.
- Cleft lip and cleft palate may happen even in children born to women who are not taking any medicines and do not have other risk factors.
- There may be other medicines to treat your condition that have a lower chance of birth defects.
- All women of childbearing age should talk to their healthcare providers about using other possible treatments instead of TOPAMAX®. If the decision is made to use TOPAMAX®, you should use effective birth control (contraception) unless you are planning to become pregnant. You should talk to your doctor about the best kind of birth control to use while you are taking TOPAMAX®.
- Tell your healthcare provider right away if you become pregnant while taking TOPAMAX®. You and your healthcare provider should decide if you will continue to take TOPAMAX® while you are pregnant.
- If you take TOPAMAX® during pregnancy, your baby may be smaller than expected at birth. The long-term effects of this are not known. Talk to your healthcare provider if you have questions about this risk during pregnancy.
- Metabolic acidosis may have harmful effects on your baby. Talk to your healthcare provider if TOPAMAX® has caused metabolic acidosis during your pregnancy.
- Pregnancy Registry: If you become pregnant while taking TOPAMAX®, talk to your healthcare provider about registering with the North American Antiepileptic Drug Pregnancy Registry. You can enroll in this registry by calling 1-888-233-2334. The purpose of this registry is to collect information about the safety of TOPAMAX® and other antiepileptic drugs during pregnancy.
Before taking TOPAMAX®, tell your healthcare provider about all of your medical conditions, including if you:
- Have or have had depression, mood problems, or suicidal thoughts or behavior
- Have kidney problems, have kidney stones, or are getting kidney dialysis
- Have a history of metabolic acidosis (too much acid in the blood)
- Have liver problems
- Have weak, brittle, or soft bones (osteomalacia, osteoporosis, osteopenia, or decreased bone density)
- Have lung or breathing problems
- Have eye problems, especially glaucoma
- Have diarrhea
- Have a growth problem
- Are on a diet high in fat and low in carbohydrates, which is called a ketogenic diet
- Are having surgery
- Are pregnant or plan to become pregnant
- Are breastfeeding or plan to breastfeed. TOPAMAX® passes into breast milk. Breastfed babies may be sleepy or have diarrhea. It is not known if the TOPAMAX® that passes into breast milk can cause serious harm to your baby. Talk to your healthcare provider about the best way to feed your baby if you take TOPAMAX®.
Tell your healthcare provider about all the medicines you take, including prescription and over-the-counter medicines, vitamins, and herbal supplements. TOPAMAX® and other medicines may affect each other causing side effects. Especially tell your healthcare provider if you take:
- Valproic acid (such as Depakene® or Depakote®).
- Any medicines that impair or decrease your thinking, concentration, or muscle coordination.
- Birth control pills. TOPAMAX® may make your birth control pills less effective. Tell your healthcare provider if your menstrual bleeding changes while you are taking birth control pills and TOPAMAX®.
Ask your healthcare provider if you are not sure if your medicine is listed above. Know the medicines you take. Keep a list of them to show your healthcare provider and pharmacist each time you get a new medicine. Do not start a new medicine without talking with your healthcare provider.
Topiramate, sold under the brand name Topamax among others, is a medication used to treat epilepsy and prevent migraines. It has also been used in alcohol dependence. For epilepsy this includes treatment for generalized or focal seizures. It is taken by mouth.
Common side effects include tingling, feeling tired, loss of appetite, abdominal pain, weight loss, and decreased cognitive function such as trouble concentrating. Serious side effects may include suicide, increased ammonia levels resulting in encephalopathy, and kidney stones. Use in pregnancy may result in harm to the baby and use during breastfeeding is not recommended. How it works is unclear.
Topiramate was approved for medical use in the United States in 1996. It is available as a generic medication. In 2020, it was the 57th most commonly prescribed medication in the United States, with more than 11 million prescriptions.
People taking topiramate should be aware of the following risks:
- Avoid activities requiring mental alertness and coordination until drug effects are realized.
- Topiramate may impair heat regulation, especially in children. Use caution with activities leading to an increased core temperature, such as strenuous exercise, exposure to extreme heat, or dehydration.
- Topiramate may cause visual field defects.
- Topiramate may decrease effectiveness of oestrogen-containing oral contraceptives.
- Taking topiramate in the first trimester of pregnancy may increase risk of cleft lip/cleft palate in infant.
- As is the case for all antiepileptic drugs, it is advisable not to suddenly discontinue topiramate as there is a theoretical risk of rebound seizures.
Very common (>10% incidence) adverse effects include:
Common (1-10% incidence) adverse effects include:
- Weight gain
- Disturbance in attention
- Memory impairment
- Cognitive disorder
- Mental impairment
- Psychomotor skills impaired
- Coordination abnormal
- Hypoaesthesia (reduced sense of touch)
- Balance disorder
- Intention tremor
- Blurred vision
- Diplopia (double vision)
- Visual disturbance
- Ear pain
- Nasal congestion
- Abdominal pain upper
- Abdominal pain
- Dry mouth
- Stomach discomfort
- Paraesthesia oral
- Abdominal discomfort
- Alopecia (hair loss)
- Muscle spasms
- Muscle twitching
- Muscular weakness
- Musculoskeletal chest pain
- Decreased appetite
- Gait disturbance
- Feeling abnormal
- Bradyphrenia (slowness of thought)
- Expressive language disorder
- Confusional state
- Mood altered
- Mood swings
- Abnormal behaviour
The U.S. Food and Drug Administration (FDA) has notified prescribers that topiramate can cause acute myopia and secondary angle closure glaucoma in a small subset of people who take topiramate regularly. The symptoms, which typically begin in the first month of use, include blurred vision and eye pain. Discontinuation of topiramate may halt the progression of the ocular damage and may reverse the visual impairment.
Preliminary data suggests that, as with several other anti-epileptic drugs, topiramate carries an increased risk of congenital malformations. This might be particularly important for women who take topiramate to prevent migraine attacks. In March 2011, the FDA notified healthcare professionals and patients of an increased risk of development of cleft lip and/or cleft palate (oral clefts) in infants born to women treated with Topamax (topiramate) during pregnancy and placed it in Pregnancy Category D.
Topiramate has been associated with a statistically significant increase in suicidality, and "suicidal thoughts or actions" is now listed as one of the possible side effects of the drug "in a very small number of people, about 1 in 500."