Qsymia
(phentermine / topiramate)Dosage & Administration
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Qsymia Prescribing Information
QSYMIA is indicated in combination with a reduced-calorie diet and increased physical activity to reduce excess body weight and maintain weight reduction long term in:
- Adults and pediatric patients aged 12 years and older with obesity
- Adults with overweight in the presence of at least one weight-related comorbid condition
Limitations of Use
- The effect of QSYMIA on cardiovascular morbidity and mortality has not been established.
- The safety and effectiveness of QSYMIA in combination with other products intended for weight loss, including prescription drugs, over-the-counter drugs, and herbal preparations, have not been established.
Recommended Testing Prior to and During Treatment with QSYMIA
Prior to QSYMIA initiation and during treatment with QSYMIA, the following is recommended:
- Obtain a negative pregnancy test before initiating QSYMIA in patients who can become pregnant and monthly during QSYMIA therapy. QSYMIA is contraindicated during pregnancy [see Contraindications (4), Warnings and Precautions (5.1), and Use in Specific Populations (8.3)] .
- Obtain a blood chemistry profile that includes bicarbonate, creatinine, and potassium in all patients, and glucose in patients with type 2 diabetes mellitus on antidiabetic medication prior to initiating QSYMIA treatment and periodically during treatment [see Warnings and Precautions (5.7, 5.8, 5.12)] .
Recommended Dosage and Administration
The recommended dosage, titration, and administration of QSYMIA are as follows:
- Take QSYMIA orally once daily in the morning with or without food. Avoid administration of QSYMIA in the evening due to the possibility of insomnia.
- The recommended starting dosage of QSYMIA is one capsule (containing 3.75 mg of phentermine and 23 mg of topiramate) (3.75 mg/23 mg) taken orally once daily for 14 days; after 14 days increase to the recommended dosage of QSYMIA 7.5 mg/46 mg orally once daily.
- After 12 weeks of treatment with QSYMIA 7.5 mg/46 mg, evaluate weight loss for adults or BMI reduction for pediatric patients aged 12 years and older. If an adult patient has not lost at least 3% of baseline body weight or a pediatric patient has not experienced a reduction of at least 3% of baseline BMI, increase the dosage to QSYMIA 11.25 mg/69 mg orally once daily for 14 days; followed by an increase in the dosage to QSYMIA 15 mg/92 mg orally once daily.
- After 12 weeks of treatment with QSYMIA 15 mg/92 mg, evaluate weight loss for adults or BMI reduction for pediatric patients aged 12 years and older. If an adult patient has not lost at least 5% of baseline body weight or a pediatric patient has not experienced a reduction of at least 5% of baseline BMI, discontinue QSYMIA [see Dosage and Administration (2.3)] , as it is unlikely that the patient will achieve and sustain clinically meaningful weight loss with continued treatment.
- Monitor the rate of weight loss in pediatric patients. If weight loss exceeds 2 lbs (0.9 kg)/week, consider dosage reduction.
Discontinuation of QSYMIA 15 mg/92 mg
Discontinue QSYMIA 15 mg/92 mg gradually by taking QSYMIA 15 mg/92 mg orally once daily every other day for at least 1 week prior to stopping treatment altogether, due to the possibility of precipitating a seizure [see Warnings and Precautions (5.9)and Drug Abuse and Dependence (9.3)] .
Recommended Dosage in Patients with Renal Impairment
- The recommended dosage in patients with mild (CrCl greater or equal to 50 and less than 80 mL/min) renal impairment is the same as the recommended dosage for patients with normal renal function [see Warnings and Precautions (5.9), Use in Specific Populations (8.6), and Clinical Pharmacology (12.3)] .
- In patients with severe [creatinine clearance (CrCl) less than 30 mL/min] or moderate (CrCl greater than or equal to 30 and less than 50 mL/min) renal impairment (CrCl calculated using the Cockcroft-Gault equation with actual body weight), the maximum recommended dosage is QSYMIA 7.5 mg/46 mg once daily.
- Avoid use of QSYMIA in patients with end-stage renal disease on dialysis.
Recommended Dosage in Patients with Hepatic Impairment
- The recommended dosage of QSYMIA in patients with mild hepatic impairment (Child-Pugh 5 - 6) is the same as the recommended dosage in patients with normal hepatic function [see Use in Specific Populations (8.7)and Clinical Pharmacology (12.3)] .
- In patients with moderate hepatic impairment (Child-Pugh score 7 - 9), the maximum recommended dosage is QSYMIA 7.5 mg/46 mg orally once daily.
- Avoid use of QSYMIA in patients with severe hepatic impairment (Child-Pugh score 10 - 15).
QSYMIA extended-release capsules are available in four strengths (phentermine mg/topiramate mg):
- 3.75 mg/23 mg - purple cap imprinted with VIVUS and purple body imprinted with 3.75/23
- 7.5 mg/46 mg - purple cap imprinted with VIVUS and yellow body imprinted with 7.5/46
- 11.25 mg/69 mg - yellow cap imprinted with VIVUS and yellow body imprinted with 11.25/69
- 15 mg/92 mg - yellow cap imprinted with VIVUS and white body imprinted with 15/92
Pregnancy
Risk Summary
QSYMIA is contraindicated in pregnant patients. The use of QSYMIA can cause fetal harm, and weight loss offers no clear clinical benefit to a pregnant patient (see Clinical Considerations) . Available data from pregnancy registries and epidemiologic studies indicate an increased risk of major congenital malformations, including but not limited to cleft lip and/or cleft palate (oral clefts), and of being SGA in infants exposed in uteroto topiramate (see Data) . When phentermine and topiramate were co-administered to rats at doses of 3.75 and 25 mg/kg, respectively [approximately 2 times the maximum recommended human dose (MRHD) based on area under the curve (AUC)], or at the same dose to rabbits (approximately 0.1 times and 1 time, respectively, the clinical exposures at the MRHD based on AUC), there were no drug-related malformations. However, structural malformations, including craniofacial defects and reduced fetal weights occurred in offspring of multiple species of pregnant animals administered topiramate at clinically relevant doses (see Data) . Advise pregnant women of the potential risk to a fetus.
Clinical Considerations
Disease Associated Maternal and/or Embryo/Fetal Risk
Weight loss during pregnancy may result in fetal harm. Appropriate weight gain based on pre-pregnancy weight is currently recommended for all pregnant patients, including those who are already overweight or obese, due to the obligatory weight gain that occurs in maternal tissues during pregnancy. Maternal obesity increases the risk for congenital malformations, including neural tube defects, cardiac malformations, oral clefts, and limb reduction defects.
Fetal/Neonatal Adverse Reactions
QSYMIA can cause metabolic acidosis [see Warnings and Precautions (5.7)] . The effect of topiramate-induced metabolic acidosis has not been studied in pregnancy; however, metabolic acidosis in pregnancy (due to other causes) can cause decreased fetal growth, decreased fetal oxygenation, and fetal death, and may affect the fetus' ability to tolerate labor.
Data
Human Data
Data evaluating the risk of major congenital malformations, oral clefts, and being SGA with topiramate exposure during pregnancy is available from the North American Antiepileptic Drug (NAAED) Pregnancy Registry and from several larger retrospective epidemiologic studies.
Major Congenital Malformations
The NAAED Pregnancy Registry indicates an increased risk of major congenital malformations, including but not limited to oral clefts in infants exposed to topiramate during the first trimester of pregnancy. Other than oral clefts, no specific pattern of major congenital malformations or grouping of major congenital malformation types were observed. In the NAAED pregnancy registry, when topiramate-exposed infants with only oral clefts were excluded, the prevalence of major congenital malformations (4.1%) was higher than that in infants exposed to a reference antiepileptic drug (AED) (1.8%) or in infants with mothers without epilepsy and without exposure to AEDs (1.1%).
Oral Clefts
In the NAAED Pregnancy Registry, the prevalence of oral clefts among topiramate-exposed infants (1.4%) was higher than the prevalence in infants exposed to a reference AED (0.3%) or the prevalence in infants with mothers without epilepsy and without exposure to AEDs (0.11%). It was also higher than the background prevalence in United States (0.17%) as estimated by the Centers for Disease Control and Prevention (CDC). The relative risk of oral clefts in topiramate-exposed pregnancies in the NAAED Pregnancy Registry was 12.5 (95% Confidence Interval [CI] 5.9-26.37) as compared to the risk in a background population of untreated women. The UK Epilepsy and Pregnancy Register reported a prevalence of oral clefts among infants exposed to topiramate monotherapy (3.2%) that was 16 times higher than the background rate in the UK (0.2%).
Larger retrospective epidemiology studies showed that topiramate monotherapy exposure in pregnancy is associated with an approximately two to five-fold increased risk of oral clefts. The FORTRESS study found an excess risk of 1.5 (95% CI = -1.1 to 4.1) oral cleft cases per 1,000 infants exposed to topiramate during the first trimester.
Small for Gestational Age
Data from the NAAED Pregnancy Registry and population-based birth registry cohort indicate that exposure to topiramate in utero is associated with an increased risk of SGA newborns (birth weight <10 thpercentile). In the NAAED Pregnancy Registry, 19.7% of topiramate-exposed newborns were SGA compared to 7.9% of newborns exposed to a reference AED and 5.4% of newborns of mothers without epilepsy and without AED exposure. In the medical Birth Registry of Norway, a population-based pregnancy registry, 25% of newborns in the topiramate monotherapy exposure group were SGA compared to 9% in the comparison group unexposed to AEDs. The long-term consequences of the SGA findings are not known.
Animal Data
Phentermine/Topiramate
Embryo-fetal development studies have been conducted in rats and rabbits with combination phentermine and topiramate treatment. Phentermine and topiramate co-administered to rats during the period of organogenesis (gestation day (GD) 6 through 17) caused reduced fetal body weights but did not cause fetal malformations at the maximum dose of 3.75 mg/kg phentermine and 25 mg/kg topiramate [approximately 2 times the maximum recommended human dose (MRHD) based on area under the curve (AUC) estimates for each active ingredient]. In a similar study in rabbits in which the same doses were administered from GD 6 through 18, no effects on embryo-fetal development were observed at approximately 0.1 times (phentermine) and 1 time (topiramate) clinical exposures at the MRHD based on AUC. Significantly lower maternal body weight gain was recorded at these doses in rats and rabbits.
A pre- and post-natal development study was conducted in rats with combination phentermine and topiramate treatment. There were no adverse maternal or offspring effects in rats treated throughout organogenesis and lactation with 1.5 mg/kg/day phentermine and 10 mg/kg/day topiramate (approximately 2- and 3-times clinical exposures at the MRHD, respectively, based on AUC). Treatment with higher doses of 11.25 mg/kg/day phentermine and 75 mg/kg/day topiramate (approximately 5 and 6 times maximum clinical doses based on AUC, respectively) caused reduced maternal body weight gain and offspring toxicity. Offspring effects included lower pup survival after birth, increased limb and tail malformations, reduced pup body weight and delayed growth, development, and sexual maturation without affecting learning, memory, or fertility and reproduction. The limb and tail malformations were consistent with results of animal studies conducted with topiramate alone.
Phentermine
Animal reproduction studies have not been conducted with phentermine. Limited data from studies conducted with the phentermine/topiramate combination indicate that phentermine alone was not teratogenic but resulted in lower body weight and reduced survival of offspring in rats at 5-fold the MRHD of QSYMIA, based on AUC.
Topiramate
Topiramate causes developmental toxicity, including teratogenicity, at clinically relevant doses in multiple animal species.
Developmental toxicity, including teratogenicity, occurred at clinically relevant doses in multiple animal species in which topiramate was administered during the period of organogenesis (GD 6 – 15 in rodents, GD 6 – 18 in rabbits. In these studies, fetal malformations (primarily craniofacial defects such as cleft palate), limb malformations (ectrodactyly, micromelia, and amelia), rib/vertebral column anomalies, and/or reduced fetal weights were observed at dosages ≥ 20 mg/kg in mice (approximately 2 times the MRHD of topiramate in QSYMIA 15 mg/92 mg on a mg/m 2basis), 20 mg/kg in rats (2 times the MRHD of QSYMIA based on estimated AUC), and 35 mg/kg in rabbits (2 times the MRHD based on estimated AUC). When rats were administered topiramate from GD 15 through lactation day 20, reductions in pre- and/or post-weaning weights occurred at dosages ≥ 2 mg/kg (2 times the MRHD of QSYMIA based on estimated AUC).
Lactation
Risk Summary
Topiramate and phentermine are present in human milk. There are no data on the effects of topiramate and phentermine on milk production. Diarrhea and somnolence have been reported in breastfed infants with maternal use of topiramate. There are no data on the effects of phentermine in breastfed infants. Because of the potential for serious adverse reactions, including changes in sleep, irritability, hypertension, vomiting, tremor, and weight loss in breastfed infants with maternal use of phentermine, advise patients that breastfeeding is not recommended during QSYMIA therapy.
Females and Males of Reproductive Potential
Pregnancy Testing
Pregnancy testing is recommended in patients who can become pregnant before initiating QSYMIA and monthly during QSYMIA therapy [see Warnings and Precautions (5.1)and Use in Specific Populations (8.1)] .
Contraception
Females
QSYMIA can cause fetal harm when administered to a pregnant patient [see Use in Specific Populations (8.1)] . Advise patients who can become pregnant to use effective contraception during therapy with QSYMIA.
For patients taking combined oral contraceptives (COCs), use of QSYMIA may cause irregular bleeding [see Drug Interactions (7)] . Advise patients not to discontinue taking their COC and to contact their health care provider.
Pediatric Use
The safety and effectiveness of QSYMIA as an adjunct to a reduced-calorie diet and increased physical activity for weight reduction and long-term maintenance of body weight have been established in pediatric patients aged 12 years and older with obesity. Use of QSYMIA for this indication is supported by a 56-week, double-blind, placebo-controlled study in 223 pediatric patients aged 12 years and above, a pharmacokinetic study in pediatric patients, and studies in adults with obesity [see Clinical Pharmacology (12.3)and Clinical Studies (14)] .
In a pediatric clinical trial, there was one episode of serious suicidal ideation in a QSYMIA-treated patient requiring hospitalization and pharmacologic treatment [see Warnings and Precautions (5.2)] more patients treated with QSYMIA versus placebo reported adverse reactions related to mood (e.g., depression, anxiety) and sleep disorders (e.g., insomnia) [see Warnings and Precautions (5.4). Increases in bone mineral density and linear growth were attenuated in QSYMIA- versus placebo-treated patients [see Warnings and Precautions (5.6)] . Serious adverse reactions seen in pediatric patients using topiramate include acute angle glaucoma, oligohidrosis and hyperthermia, metabolic acidosis, cognitive and neuropsychiatric reactions, hyperammonemia and encephalopathy, and kidney stones.
The safety and effectiveness of QSYMIA in pediatric patients below the age of 12 years have not been established.
Geriatric Use
In the QSYMIA clinical trials, a total of 254 (7%) of the patients were 65 to 69 years of age; no patients 70 years of age or older were enrolled.
Clinical studies of QSYMIA did not include sufficient numbers of patients aged 65 and over to determine whether they respond differently from younger patients. In general, dose selection for an elderly patient should be cautious, usually starting at the low end of the dosing range, reflecting the greater frequency of decreased hepatic, renal, or cardiac function, and of concomitant disease or other drug therapy.
Renal Impairment
Compared to healthy volunteers with normal renal function, patients with moderate and severe renal impairment as estimated by the Cockcroft-Gault equation had higher exposures to phentermine and topiramate.
The recommended dosage of QSYMIA in patients with mild renal impairment (CrCl greater or equal to 50 and less than 80 mL/min) is the same as the recommended dosage for patients with normal renal function.
In patients with moderate (CrCl greater than or equal to 30 to less than 50 mL/min) and severe (CrCl less than 30 mL/min) renal impairment, the maximum recommended dosage is QSYMIA 7.5 mg/46 mg once daily.
QSYMIA has not been studied in patients with end-stage renal disease on dialysis. Avoid QSYMIA in this patient population [see Dosage and Administration (2.4)and Clinical Pharmacology (12.3)] .
Hepatic Impairment
In patients with mild (Child-Pugh 5 - 6) and moderate (Child-Pugh 7 - 9) hepatic impairment, exposure to phentermine was higher compared to healthy volunteers with normal hepatic function. Exposure to topiramate was similar among patients with mild and moderate hepatic impairment and healthy volunteers.
The recommended dosage of QSYMIA in patients with mild hepatic impairment (Child-Pugh 5 - 6) is the same as the recommended dosage in patients with normal hepatic function.
In patients with moderate hepatic impairment, the maximum recommended dosage is QSYMIA 7.5 mg/46 mg once daily.
QSYMIA has not been studied in patients with severe hepatic impairment (Child-Pugh score 10 - 15). Avoid QSYMIA in this patient population [see Dosage and Administration (2.5)and Clinical Pharmacology (12.3)] .
QSYMIA is contraindicated in patients:
- Who are pregnant [see Warnings and Precautions (5.1)and Use in Specific Populations (8.1)]
- With glaucoma [see Warnings and Precautions (5.3)]
- With hyperthyroidism
- Taking or within 14 days of stopping a monoamine oxidase inhibitors [see Drug Interactions (7)]
- With known hypersensitivity to phentermine, topiramate or any of the excipients in QSYMIA, or idiosyncrasy to the sympathomimetic amines [see Adverse Reactions (6.2)] .
Embryo-Fetal Toxicity
QSYMIA can cause fetal harm. Data from pregnancy registries and epidemiologic studies indicate that a fetus exposed to topiramate in the first trimester of pregnancy has an increased risk of major congenital malformations, including but not limited to cleft lip and/or cleft palate (oral clefts), and of being small for gestational age (SGA). When multiple species of pregnant animals received topiramate at clinically relevant doses, structural malformations, including craniofacial defects, and reduced fetal weights occurred in offspring. A negative pregnancy test is recommended before initiating QSYMIA treatment in patients who can become pregnant and monthly during QSYMIA therapy. Advise patients who can become pregnant of the potential risk to a fetus and to use effective contraception during QSYMIA therapy [see Use in Specific Populations (8.1, 8.3)] .
QSYMIA Risk Evaluation and Mitigation Strategy (REMS)
Because of the teratogenic risk associated with QSYMIA therapy, QSYMIA is available through a limited program under the REMS. Under the QSYMIA REMS, only certified pharmacies may distribute QSYMIA. Further information is available at www.QSYMIAREMS.com or by telephone at 1-888-998-4887.
Suicidal Behavior and Ideation
Antiepileptic drugs (AEDs), including topiramate, increase the risk of suicidal thoughts or behavior in patients taking these drugs for any indication. Pooled analyses of 199 placebo-controlled clinical studies (monotherapy and adjunctive therapy, median treatment duration 12 weeks) of 11 different AEDs across several indications 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. 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 AED-treated patients in the trials and none in placebo-treated patients, but the number is too small to allow any conclusion about AED effect on suicide. The increased risk of suicidal thoughts or behavior with AEDs was observed as early as 1 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 in the clinical trials analyzed.
In a QSYMIA clinical trial of pediatric patients aged 12 years and older, 1 (0.6%) of the 167 QSYMIA-treated patients reported suicidal ideation and behavior which required hospitalization. No placebo-treated patients reported suicidal behavior or ideation.
Monitor all patients for the emergence or worsening of depression, suicidal thoughts or behavior, and/or any unusual changes in mood or behavior. Discontinue QSYMIA in patients who experience suicidal thoughts or behaviors [see Warnings and Precautions (5.9)] . Avoid QSYMIA in patients with a history of suicidal attempts or active suicidal ideation.
Risk of Ophthalmologic Adverse Reactions
Acute Myopia and Secondary Angle Closure Glaucoma
A syndrome consisting of acute myopia associated with secondary angle closure glaucoma has been reported in patients treated with topiramate. Symptoms include acute onset of decreased visual acuity and/or ocular pain. Ophthalmologic findings can include myopia, mydriasis, anterior chamber shallowing, ocular hyperemia (redness), choroidal detachments, retinal pigment epithelial detachments, macular striae, and increased intraocular pressure. 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 treatment with topiramate but may occur at any time during 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 QSYMIA as rapidly as possible in consultation with the treating physician. Elevated intraocular pressure of any etiology, if left untreated, can lead to serious sequelae including permanent loss of vision.
Visual Field Defects
Visual field defects (independent of elevated intraocular pressure) have been reported in clinical trials and in postmarketing experience in patients receiving topiramate. In clinical trials, most of these events were reversible after topiramate discontinuation. If visual problems occur at any time during treatment, consider discontinuing QSYMIA.
Mood and Sleep Disorders
QSYMIA can cause mood disorders, including depression and anxiety, as well as insomnia. Patients with a history of depression may be at increased risk of recurrent depression or other mood disorders while taking QSYMIA [see Adverse Reactions (6.1)] .
Consider dosage reduction or discontinuation of QSYMIA if clinically significant or persistent symptoms occur. Discontinue QSYMIA if patients have symptoms of suicidal ideation or behavior [see Warnings and Precautions (5.2)] .
Cognitive Impairment
QSYMIA can cause cognitive dysfunction (e.g., impairment of concentration/attention, difficulty with memory, and speech or language problems, particularly word-finding difficulties). Rapid titration or high initial doses of QSYMIA may be associated with higher rates of cognitive events such as attention, memory, and language/word-finding difficulties [see Adverse Reactions (6.1)] . The concomitant use of alcohol or central nervous system (CNS) depressant drugs with QSYMIA may potentiate CNS depression or other centrally mediated effects of these agents, such as dizziness, cognitive adverse reactions, drowsiness, light-headedness, impaired coordination, and somnolence.
Caution patients about operating hazardous machinery, including automobiles, until they are reasonably certain QSYMIA therapy does not affect them adversely. Caution patients against excessive alcohol intake while receiving QSYMIA.
If cognitive dysfunction persists, consider dosage reduction or discontinuation of QSYMIA [see Warnings and Precautions (5.9)] .
Slowing of Linear Growth
QSYMIA is associated with a reduction in height velocity (centimeters of height gained per year) in obese pediatric patients 12 to 17 years of age. In a 56-week study, average height increased from baseline in both QSYMIA- and placebo-treated patients; however, a lower height velocity of -1.3 to -1.4 cm/year was observed in QSYMIA-treated compared to placebo-treated patients. Monitor height velocity in pediatric patients treated with QSYMIA. Consider dosage reduction or discontinuation of QSYMIA if pediatric patients are not growing or gaining height as expected [see Warnings and Precautions (5.9)] .
Metabolic Acidosis
Hyperchloremic, non-anion gap, metabolic acidosis (decreased serum bicarbonate below the normal reference range in the absence of chronic respiratory alkalosis) has been reported in patients treated with QSYMIA [see Adverse Reactions (6.1)] . Manifestations of acute or chronic metabolic acidosis may include hyperventilation, nonspecific symptoms such as fatigue and anorexia, or more severe sequelae including cardiac arrhythmias or stupor. Chronic, untreated metabolic acidosis may increase the risk for nephrolithiasis or nephrocalcinosis and may also result in osteomalacia (referred to as rickets in pediatric patients) and/or osteoporosis with an increased risk for fractures. Chronic metabolic acidosis in pediatric patients may also reduce growth rates, which may decrease the maximal height achieved.
Conditions or therapies that predispose to acidosis (i.e., renal disease, severe respiratory disorders, status epilepticus, diarrhea, surgery, or ketogenic diet) may be additive to the bicarbonate lowering effects of QSYMIA. Concomitant use of QSYMIA and a carbonic anhydrase inhibitor may increase the severity of metabolic acidosis and may also increase the risk of kidney stone formation [see Warnings and Precautions (5.10)] . Avoid use of QSYMIA with other carbonic anhydrase inhibitors. If concomitant use of QSYMIA with another carbonic anhydrase inhibitor is unavoidable, the patient should be monitored for the appearance or worsening of metabolic acidosis.
Measure electrolytes including serum bicarbonate prior to starting QSYMIA and during QSYMIA treatment. In QSYMIA clinical trials, the peak reduction in serum bicarbonate typically occurred within 4 weeks of titration to the assigned dose, and in most patients, there was a correction of bicarbonate by week 56, without any dosage reduction. However, if persistent metabolic acidosis develops while taking QSYMIA, reduce the dosage or discontinue QSYMIA [see Warnings and Precautions (5.9)] .
Decrease in Renal Function
QSYMIA can cause an increase in serum creatinine that reflects a decrease in renal function (glomerular filtration rate). In clinical trials, peak increases in serum creatinine were observed after 4 to 8 weeks of treatment. On average, serum creatinine gradually declined but remained elevated over baseline creatinine values. The changes in serum creatinine (and measured GFR) with short-term (4-weeks) QSYMIA treatment appear reversible with treatment discontinuation, but the effect of chronic treatment on renal function is not known.
Measure serum creatinine prior to starting QSYMIA and during QSYMIA treatment. If persistent elevations in creatinine occur, reduce the dosage or discontinue QSYMIA [see Warnings and Precautions (5.9), Adverse Reactions (6.1), and Clinical Pharmacology (12.2)] .
Risk of Seizures with Abrupt Withdrawal of QSYMIA
Abrupt withdrawal of topiramate has been associated with seizures in individuals without a history of seizures or epilepsy. In situations where immediate termination of QSYMIA is medically required, appropriate monitoring is recommended. Patients discontinuing QSYMIA 15 mg/92 mg should be gradually tapered to reduce the possibility of precipitating a seizure [see Dosage and Administration (2.3)and Drug Abuse and Dependence (9.3)] .
Kidney Stones
QSYMIA has been associated with kidney stone formation [see Adverse Reactions (6.1)] . Topiramate inhibits carbonic anhydrase activity and promotes kidney stone formation by reducing urinary citrate excretion and increasing urine pH. Patients on a ketogenic diet may be at increased risk for kidney stone formation. An increase in urinary calcium and a marked decrease in urinary citrate was observed in topiramate-treated pediatric patients in a one-year, active-controlled study. Increased ratio of urinary calcium/citrate increases the risk of kidney stones and/or nephrocalcinosis.
Avoid the use of QSYMIA with other drugs that inhibit carbonic anhydrase [see Drug Interactions (7)] . Advise patients to increase fluid intake (to increase urinary output), which may decrease the concentration of substances involved in kidney stone formation.
Oligohidrosis and Hyperthermia
Oligohidrosis (decreased sweating), infrequently resulting in hospitalization, has been reported in association with the use of topiramate. Decreased sweating and an elevation in body temperature above normal characterized these cases. Some of the cases have been reported with topiramate after exposure to elevated environmental temperatures.
The majority of the reports associated with topiramate have been in pediatric patients. Advise all patients and caregivers to monitor for decreased sweating and increased body temperature during physical activity, especially in hot weather. Patients on concomitant medications that predispose them to heat-related disorders may be at increased risk.
Hypokalemia
QSYMIA can increase the risk of hypokalemia through its inhibition of carbonic anhydrase activity. In addition, when QSYMIA is used in conjunction with non-potassium sparing diuretics this may further potentiate potassium-wasting. Measure potassium before and during treatment with QSYMIA [see Adverse Reactions (6.1), Drug Interactions (7), and Clinical Pharmacology (12.3)] .
Serious Skin Reactions
Serious skin reactions (Stevens-Johnson Syndrome [SJS] and Toxic Epidermal Necrolysis [TEN]) have been reported in patients receiving topiramate. QSYMIA should be discontinued at the first sign of a rash, unless the rash is clearly not drug-related. If signs or symptoms suggest SJS/TEN, use of this drug should not be resumed, and alternative therapy should be considered. Inform patients about the signs of serious skin reactions.
Allergic Reactions Due to Inactive Ingredient FD&C Yellow No. 5
This product contains FD&C Yellow No. 5 (tartrazine) which may cause allergic-type reactions (including bronchial asthma) in certain susceptible persons. Although the overall incidence of FD&C Yellow No. 5 (tartrazine) sensitivity in the general population is low, it is frequently seen in patients who also have aspirin hypersensitivity.