Qsymia

Last updated on RxList: 4/8/2021
Qsymia Side Effects Center

What Is Qsymia?

Qsymia (phentermine and topiramate extended-release) is a combination appetite suppressant/stimulant and seizure medication indicated as an adjunct to a reduced-calorie diet and increased physical activity for chronic weight management in overweight and obese adults.

What Are Side Effects of Qsymia?

Side effects of Qsymia can include:

Dosage for Qsymia

Dosing of Qsymia is based on the body mass index (BMI) of the patient. Start treatment with Qsymia 3.75 mg/23 mg (phentermine 3.75 mg/topiramate 23 mg extended-release) daily for 14 days; after 14 days increase to the recommended dose of Qsymia 7.5 mg/46 mg (phentermine 7.5 mg/topiramate 46 mg extended-release) once daily. Weight loss should be evaluated 12 weeks after the start of treatment.

What Drugs, Substances, or Supplements Interact with Qsymia?

Other medications may interact with Qsymia. Tell your doctor all medications you use.

Qsymia During Pregnancy and Breastfeeding

If this drug is used during pregnancy, or if a patient becomes pregnant while taking this drug, treatment should be discontinued immediately and the patient should be apprised of the potential hazard to a fetus. It is not known if Qsymia passes into breast milk. Consult your doctor before breastfeeding. Withdrawal symptoms may occur if you suddenly stop taking this medication.

Additional Information

Our Qsymia Side Effects Drug Center provides a comprehensive view of available drug information on the potential side effects when taking this medication.

This is not a complete list of side effects and others may occur. Call your doctor for medical advice about side effects. You may report side effects to FDA at 1-800-FDA-1088.

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Qsymia Consumer Information

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Get emergency medical help if you have signs of an allergic reaction: hives; difficulty breathing; swelling of your face, lips, tongue, or throat.

Report any new or worsening symptoms to your doctor, such as: mood or behavior changes, anxiety, panic attacks, trouble sleeping, or if you feel impulsive, irritable, agitated, hostile, aggressive, restless, hyperactive (mentally or physically), depressed, or have thoughts about suicide or hurting yourself.

Call your doctor at once if you have:

  • unusual changes in mood or behavior;
  • confusion, trouble concentrating, problems with speech or memory;
  • fast or pounding heartbeats while you are resting;
  • a seizure;
  • signs of a kidney stone--severe pain in your side or lower back, painful or difficult urination; or
  • signs of too much acid in your blood--loss of appetite, tiredness, thinking problems, irregular heartbeats.

Common side effects may include:

  • dizziness;
  • constipation;
  • numbness or tingly feeling;
  • sleep problems (insomnia); or
  • dry mouth, changes in your sense of taste.

This is not a complete list of side effects and others may occur. Call your doctor for medical advice about side effects. You may report side effects to FDA at 1-800-FDA-1088.

Read the entire detailed patient monograph for Qsymia (Phentermine and Topiramate)

Qsymia Professional Information

SIDE EFFECTS

The following important adverse reactions are described below and elsewhere in the labeling:

  • Fetal Toxicity: [see WARNINGS AND PRECAUTIONS and Use In Specific Populations]
  • Elevation in Heart Rate [see WARNINGS AND PRECAUTIONS]
  • Suicidal Behavior and Ideation [see WARNINGS AND PRECAUTIONS]
  • Acute Angle Closure Glaucoma [see WARNINGS AND PRECAUTIONS]
  • Mood and Sleep Disorders [see WARNINGS AND PRECAUTIONS]
  • Cognitive Impairment [see WARNINGS AND PRECAUTIONS]
  • Metabolic Acidosis [see WARNINGS AND PRECAUTIONS]

Clinical Trials Experience

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 studies of another drug and may not reflect the rates observed in practice.

The data described herein reflects exposure to Qsymia in two, 1-year, randomized, double-blind, placebo-controlled, multicenter clinical trials, and two Phase 2 supportive trials in 2318 adult patients (936 [40.4%] patients with hypertension, 309 [13.3%] patients with type 2 diabetes, 808 [34.9%] patients with BMI greater than 40 kg/m2) exposed for a mean duration of 298 days.

Common Adverse Reactions

Adverse reactions occurring at a rate of greater than or equal to 5% and at a rate at least 1.5 times placebo include paraesthesia, dizziness, dysgeusia, insomnia, constipation, and dry mouth.

Adverse reactions reported in greater than or equal to 2% of Qsymia-treated patients and more frequently than in the placebo group are shown in Table 3.

Table 3. Adverse Reactions Reported in Greater Than or Equal to 2% of Patients and More Frequently than Placebo during 1 Year of Treatment – Overall Study Population

System Organ Class
   Preferred Term
Placebo
(N = 1561)
%
Qsymia
3.75 mg/23 mg
(N = 240)
%
Qsymia
7.5 mg/46 mg
(N = 498)
%
Qsymia
15 mg/92 mg
(N = 1580)
%
Nervous System Disorders
  Paraesthesia 1.9 4.2 13.7 19.9
  Headache 9.3 10.4 7.0 10.6
  Dizziness 3.4 2.9 7.2 8.6
  Dysgeusia 1.1 1.3 7.4 9.4
  Hypoesthesia 1.2 0.8 3.6 3.7
  Disturbance in Attention 0.6 0.4 2.0 3.5
Psychiatric Disorders
  Insomnia 4.7 5.0 5.8 9.4
  Depression 2.2 3.3 2.8 4.3
  Anxiety 1.9 2.9 1.8 4.1
Gastrointestinal Disorders
  Constipation 6.1 7.9 15.1 16.1
  Dry Mouth 2.8 6.7 13.5 19.1
  Nausea 4.4 5.8 3.6 7.2
  Diarrhea 4.9 5.0 6.4 5.6
  Dyspepsia 1.7 2.1 2.2 2.8
  Gastroesophageal Reflux Disease 1.3 0.8 3.2 2.6
  Paraesthesia Oral 0.3 0.4 0.6 2.2
General Disorders and Administration Site Conditions
  Fatigue 4.3 5.0 4.4 5.9
  Irritability 0.7 1.7 2.6 3.7
  Thirst 0.7 2.1 1.8 2.0
  Chest Discomfort 0.4 2.1 0.2 0.9
Eye Disorders
  Vision Blurred 3.5 6.3 4.0 5.4
  Eye Pain 1.4 2.1 2.2 2.2
  Dry Eye 0.8 0.8 1.4 2.5
Cardiac Disorders
  Palpitations 0.8 0.8 2.4 1.7
Skin and Subcutaneous Tissue Disorders
  Rash 2.2 1.7 2.0 2.6
  Alopecia 0.7 2.1 2.6 3.7
Metabolism and Nutrition Disorders
  Hypokalemia 0.4 0.4 1.4 2.5
  Decreased Appetite 0.6 2.1 1.8 1.5
Reproductive System and Breast Disorders
  Dysmenorrhea 0.2 2.1 0.4 0.8
Infections and Infestations
  Upper Respiratory Tract Infection 12.8 15.8 12.2 13.5
  Nasopharyngitis 8.0 12.5 10.6 9.4
  Sinusitis 6.3 7.5 6.8 7.8
  Bronchitis 4.2 6.7 4.4 5.4
  Influenza 4.4 7.5 4.6 4.4
  Urinary Tract Infection 3.6 3.3 5.2 5.2
  Gastroenteritis 2.2 0.8 2.2 2.5
Musculoskeletal and Connective Tissue Disorders
  Back Pain 5.1 5.4 5.6 6.6
  Pain in Extremity 2.8 2.1 3.0 3.0
  Muscle Spasms 2.2 2.9 2.8 2.9
  Musculoskeletal Pain 1.2 0.8 3.0 1.6
  Neck Pain 1.3 1.3 2.2 1.2
Respiratory, Thoracic, and Mediastinal Disorders
  Cough 3.5 3.3 3.8 4.8
  Sinus Congestion 2.0 2.5 2.6 2.0
  Pharyngolaryngeal Pain 2.0 2.5 1.2 2.3
  Nasal Congestion 1.4 1.7 1.2 2.0
Injury, Poisoning, and Procedural Complications
  Procedural Pain 1.7 2.1 2.4 1.9

Paraesthesia/Dysgeusia

Reports of paraesthesia, characterized as tingling in hands, feet, or face, occurred in 4.2%, 13.7%, and 19.9% of patients treated with Qsymia 3.75 mg/23 mg, 7.5 mg/46 mg, and 15 mg/92 mg, respectively, compared to 1.9% of patients treated with placebo. Dysgeusia was characterized as a metallic taste, and occurred in 1.3%, 7.4%, and 9.4% of patients treated with Qsymia 3.75 mg/23 mg, 7.5 mg/46 mg, and 15 mg/92 mg, respectively, compared to 1.1% of patients treated with placebo. The majority of these events first occurred within the initial 12 weeks of drug therapy; however, in some patients, events were reported later in the course of treatment. Only Qsymia-treated patients discontinued treatment due to these events (1% for paraesthesia and 0.6% for dysgeusia).

Mood and Sleep Disorders

The proportion of patients in 1-year controlled trials of Qsymia reporting one or more adverse reactions related to mood and sleep disorders was 15.8%, 14.5%, and 20.6% with Qsymia 3.75 mg/23 mg, 7.5 mg/46 mg, and 15 mg/92 mg, respectively, compared to 10.3% with placebo. These events were further categorized into sleep disorders, anxiety, and depression. Reports of sleep disorders were typically characterized as insomnia, and occurred in 6.7%, 8.1%, and 11.1% of patients treated with Qsymia 3.75 mg/23 mg, 7.5 mg/46 mg, and 15 mg/92 mg, respectively, compared to 5.8% of patients treated with placebo. Reports of anxiety occurred in 4.6%, 4.8%, and 7.9% of patients treated with Qsymia 3.75 mg/23 mg, 7.5 mg/46 mg, and 15 mg/92 mg, respectively, compared to 2.6% of patients treated with placebo. Reports of depression/mood problems occurred in 5.0%, 3.8%, and 7.6% of patients treated with Qsymia 3.75 mg/23 mg, 7.5 mg/46 mg, and 15 mg/92 mg, respectively, compared to 3.4% of patients treated with placebo. The majority of these events first occurred within the initial 12 weeks of drug therapy; however, in some patients, events were reported later in the course of treatments. In the Qsymia clinical trials, the overall prevalence of mood and sleep adverse reactions was approximately twice as great in patients with a history of depression compared to patients without a history of depression; however, the proportion of patients on active treatment versus placebo who reported mood and sleep adverse reactions was similar in these two subgroups. Occurrence of depression-related events was more frequent in patients with a past history of depression across all treatment groups. However, the placebo-adjusted difference in incidence of these events remained constant between groups regardless of previous depression history.

Cognitive Disorders

In the 1-year controlled trials of Qsymia, the proportion of patients who experienced one or more cognitive-related adverse reactions was 2.1% for Qsymia 3.75 mg/23 mg, 5.0% for Qsymia 7.5 mg/46 mg, and 7.6% for Qsymia 15 mg/92 mg, compared to 1.5% for placebo. These adverse reactions were comprised primarily of reports of problems with attention/concentration, memory, and language (word finding). These events typically began within the first 4 weeks of treatment, had a median duration of approximately 28 days or less, and were reversible upon discontinuation of treatment; however, individual patients did experience events later in treatment, and events of longer duration.

Laboratory Abnormalities

Serum Bicarbonate

In the 1-year controlled trials of Qsymia, the incidence of persistent treatment-emergent decreases in serum bicarbonate below the normal range (levels of less than 21 mEq/L at 2 consecutive visits or at the final visit) was 8.8% for Qsymia 3.75 mg/23 mg, 6.4% for Qsymia 7.5 mg/46 mg, and 12.8% for Qsymia 15 mg/92 mg, compared to 2.1% for placebo. The incidence of persistent, markedly low serum bicarbonate values (levels of less than 17 mEq/L on 2 consecutive visits or at the final visit) was 1.3% for Qsymia 3.75 mg/23 mg, 0.2% for Qsymia 7.5 mg/46 mg dose, and 0.7% for Qsymia 15 mg/92 mg dose, compared to 0.1% for placebo. Generally, decreases in serum bicarbonate levels were mild (average 1-3 mEq/L) and occurred early in treatment (4-week visit), however severe decreases and decreases later in treatment occurred.

Serum Potassium

In the 1-year controlled trials of Qsymia, the incidence of persistent low serum potassium values (less than 3.5 mEq/L at two consecutive visits or at the final visit) during the trial was 0.4% for Qsymia 3.75 mg/23 mg, 3.6% for Qsymia 7.5 mg/46 mg dose, and 4.9% for Qsymia 15 mg/92 mg, compared to 1.1% for placebo. Of the subjects who experienced persistent low serum potassium, 88% were receiving treatment with a non-potassium sparing diuretic.

The incidence of markedly low serum potassium (less than 3 mEq/L, and a reduction from pre-treatment of greater than 0.5 mEq/L) at any time during the trial was 0.0% for Qsymia 3.75 mg/23 mg, 0.2% for Qsymia 7.5 mg/46 mg dose, and 0.7% for Qsymia 15 mg/92 mg dose, compared to 0.0% for placebo. Persistent markedly low serum potassium (less than 3 mEq/L, and a reduction from pre-treatment of greater than 0.5 mEq/L at two consecutive visits or at the final visit) occurred in 0.0% of subjects receiving Qsymia 3.75 mg/23 mg, 0.2% receiving Qsymia 7.5 mg/46 mg dose, and 0.1% receiving Qsymia 15 mg/92 mg dose, compared to 0.0% receiving placebo.

Hypokalemia was reported by 0.4% of subjects treated with Qsymia 3.75 mg/23 mg, 1.4% of subjects treated with Qsymia 7.5 mg/46 mg, and 2.5% of subjects treated with Qsymia 15 mg/92 mg compared to 0.4% of subjects treated with placebo. “Blood potassium decreased” was reported by 0.4% of subjects treated with Qsymia 3.75 mg/23 mg, 0.4% of subjects treated with Qsymia 7.5 mg/46 mg, 1.0% of subjects treated with Qsymia 15 mg/92 mg, and 0.0% of subjects treated with placebo.

Serum Creatinine

In the 1-year controlled trials of Qsymia, there was a dose-related increase from baseline, peaking between Week 4 to 8, which declined but remained elevated over baseline over 1 year of treatment. The incidence of increases in serum creatinine of greater than or equal to 0.3 mg/dL at any time during treatment was 2.1% for Qsymia 3.75 mg/23 mg, 7.2% for Qsymia 7.5 mg/46 mg, and 8.4% for Qsymia 15 mg/92 mg, compared to 2.0% for placebo. Increases in serum creatinine of greater than or equal to 50% over baseline occurred in 0.8% of subjects receiving Qsymia 3.75 mg/23 mg, 2.0% receiving Qsymia 7.5 mg/46 mg, and 2.8% receiving Qsymia 15 mg/92 mg, compared to 0.6% receiving placebo.

Nephrolithiasis

In the 1-year controlled trials of Qsymia, the incidence of nephrolithiasis was 0.4% for Qsymia 3.75 mg/23 mg, 0.2% for Qsymia 7.5 mg/46 mg, and 1.2% for Qsymia 15 mg/92 mg, compared to 0.3% for placebo.

Drug Discontinuation Due To Adverse Reactions

In the 1-year placebo-controlled clinical studies, 11.6% of Qsymia 3.75 mg/23 mg, 11.6% of Qsymia 7.5 mg/46 mg, 17.4% of Qsymia 15 mg/92 mg, and 8.4% of placebo-treated patients discontinued treatment due to reported adverse reactions. The most common adverse reactions that led to discontinuation of treatment are shown in Table 4.

Table 4. Adverse Reactions Greater Than or Equal To 1% Leading to Treatment Discontinuation (1-Year Clinical Trials)

Adverse Reaction Leading to Treatment Discontinuationa Placebo
(N=1561)
%
Qsymia
3.75 mg/23 mg
(N=240)
%
Qsymia
7.5 mg/46 mg
(N=498)
%
Qsymia
15 mg/92 mg
(N=1580)
%
  Vision blurred 0.5 2.1 0.8 0.7
  Headache 0.6 1.7 0.2 0.8
  Irritability 0.1 0.8 0.8 1.1
  Dizziness 0.2 0.4 1.2 0.8
  Paraesthesia 0.0 0.4 1.0 1.1
  Insomnia 0.4 0.0 0.4 1.6
  Depression 0.2 0.0 0.8 1.3
  Anxiety 0.3 0.0 0.2 1.1
a greater than or equal to 1% in any treatment group

Postmarketing Experience

The following adverse reactions have been reported during post approval use of phentermine and topiramate, the components of Qsymia. Because these reactions are reported voluntarily from a population of uncertain size it is not always possible to reliably estimate their frequency or establish a causal relationship to drug exposure.

Qsymia

Psychiatric Disorders

Suicidal ideation, Suicidal behavior

Ophthalmic disorders

Acute angle closure glaucoma

Increased intraocular pressure

Phentermine

Allergic adverse reactions

Urticaria

Cardiovascular adverse reactions

Elevation of blood pressure, Ischemic events

Central nervous system adverse reactions

Euphoria, Psychosis, Tremor

Reproductive adverse reactions

Changes in libido, Impotence

Topiramate

Dermatologic disorders

Bullous skin reactions (including erythema multiforme, Stevens-Johnson syndrome, toxic epidermal necrolysis), Pemphigus

Gastrointestinal disorders

Pancreatitis

Hepatic disorders

Hepatic failure (including fatalities), Hepatitis

Metabolic disorders

Hyperammonemia

Hypothermia

Ophthalmic disorders

Maculopathy

DRUG INTERACTIONS

Monoamine Oxidase Inhibitors

Use of phentermine is contraindicated during or within 14 days following the administration of monoamine oxidase inhibitors because of the risk of hypertensive crisis.

Oral Contraceptives

Co-administration of multiple-dose Qsymia 15 mg/92 mg once daily with a single dose of oral contraceptive containing 35 μg ethinyl estradiol (estrogen component) and 1 mg norethindrone (progestin component), in obese otherwise healthy volunteers, decreased the exposure of ethinyl estradiol by 16% and increased the exposure of norethindrone by 22% [see CLINICAL PHARMACOLOGY].

Although this study did not specifically address the impact of the interaction on contraceptive efficacy, an increased risk of pregnancy is not anticipated. The primary determinant of contraceptive efficacy is the progestin component of the combination oral contraceptive, so higher exposure to the progestin would not be expected to be deleterious.

However, irregular bleeding (spotting) may occur more frequently due to both the increased exposure to the progestin and lower exposure to the estrogen, which tends to stabilize the endometrium. Patients should be informed not to discontinue their combination oral contraceptive if spotting occurs, but to notify their healthcare provider if the spotting is troubling to them.

CNS Depressants Including Alcohol

Specific drug interaction studies of Qsymia and alcohol or other CNS depressant drugs have not been performed. The concomitant use of alcohol or CNS depressant drugs (e.g., barbiturates, benzodiazepines, and sleep medications) with phentermine or topiramate may potentiate CNS depression such as dizziness or cognitive adverse reactions, or other centrally mediated effects of these agents. Therefore, if Qsymia is used with alcohol or other CNS depressants, the patient should be counseled regarding possible increased risk of CNS depression or side effects.

Non-Potassium Sparing Diuretics

Concurrent use of Qsymia with non-potassium sparing diuretics may potentiate the potassium-wasting action of these diuretics. Concomitant administration of hydrochlorothiazide alone with topiramate alone has been shown to increase the Cmax and AUC of topiramate by 27% and 29%, respectively. When prescribing Qsymia in the presence of non-potassium-sparing medicinal products, patients should be monitored for hypokalemia [see WARNINGS AND PRECAUTIONS and CLINICAL PHARMACOLOGY].

Antiepileptic Drugs

Concomitant administration of phenytoin or carbamazepine with topiramate in patients with epilepsy, decreased plasma concentrations of topiramate by 48% and 40%, respectively, when compared to topiramate given alone [see CLINICAL PHARMACOLOGY].

Concomitant administration of valproic acid and topiramate has been associated with hyperammonemia with and without encephalopathy. Concomitant administration of topiramate with valproic acid in patients has also been associated with hypothermia (with and without hyperammonemia). It may be prudent to examine blood ammonia in patients in whom the onset of hypothermia or encephalopathy has been reported [see CLINICAL PHARMACOLOGY].

Carbonic Anhydrase Inhibitors

Concomitant use of topiramate, a component of Qsymia, with any other carbonic anhydrase inhibitor (e.g., zonisamide, acetazolamide, or dichlorphenamide) may increase the severity of metabolic acidosis and may also increase the risk of kidney stone formation. Avoid the use of Qsymia with other drugs that inhibit carbonic anhydrase [see WARNINGS AND PRECAUTIONS].

Pioglitazone

A decrease in the exposure of pioglitazone and its active metabolites were noted with the concurrent use of pioglitazone and topiramate in a clinical trial. The clinical relevance of these observations is unknown; however, when Qsymia is added to pioglitazone therapy or pioglitazone is added to Qsymia therapy, careful attention should be given to the routine monitoring of patients for adequate control of their diabetic disease state [see CLINICAL PHARMACOLOGY].

Drug Abuse And Dependence

Controlled Substance

Qsymia is controlled in Schedule IV of the Controlled Substances Act because it contains phentermine a Schedule IV drug. Any material, compound, mixture, or preparation that contains any quantity of phentermine is controlled as a Schedule IV drug.

Topiramate is not controlled in the Controlled Substances Act.

Abuse

Phentermine, a component of Qsymia, has a known potential for abuse.

Phentermine, a component of Qsymia, is related chemically and pharmacologically to the amphetamines. Amphetamines and other stimulant drugs have been extensively abused and the possibility of abuse of phentermine should be kept in mind when evaluating the desirability of including Qsymia as part of a weight reduction program. Abuse of amphetamines and related drugs (e.g., phentermine) may be associated with impaired control over drug use and severe social dysfunction. There are reports of patients who have increased the dosage of these drugs to many times than recommended.

Dependence

Qsymia has not been systematically studied for its potential to produce physical dependence. Physical dependence is a state that develops as a result of physiological adaptation in response to repeated drug use. Physical dependence manifests by drug-class-specific withdrawal symptoms after abrupt discontinuation or a significant dose reduction of a drug.

Limited information on the potential for physical dependence for the individual components of Qsymia is available. For topiramate, abrupt discontinuation has been associated with seizures in patients without a history of seizures or epilepsy. For phentermine, abrupt cessation following prolonged high dosage administration results in extreme fatigue and mental depression; changes are also noted on a sleep electroencephalogram. Thus, in situations where rapid withdrawal of Qsymia is required, appropriate medical monitoring is recommended.

Read the entire FDA prescribing information for Qsymia (Phentermine and Topiramate)

© Qsymia Patient Information is supplied by Cerner Multum, Inc. and Qsymia Consumer information is supplied by First Databank, Inc., used under license and subject to their respective copyrights.

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