Paresthesia (tingling in hands, feet, or face,) occurred in approximately 14% of subjects given the lower doses of Qsymia (7.5 mg phentermine / 46 mg topiramate), and in 20% of patients given the higher dose of Qsymia (15 mg phentermine / 92 mg topiramate) according to the prescribing information for the drug.

Dry Mouth occurred in approximately 14% of subjects given the lower doses of Qsymia (7.5 mg phentermine / 46 mg topiramate), and in 19% of patients given the higher dose of Qsymia (15 mg phentermine / 92 mg topiramate) according to the prescribing information for the drug.

Constipation occurred in approximately 15% of subjects given the lower doses of Qsymia (7.5 mg phentermine / 46 mg topiramate), and in 16% of patients given the higher dose of Qsymia (15 mg phentermine / 92 mg topiramate) according to the prescribing information for the drug.

Dizziness occurred in approximately 7% of subjects given the lower doses of Qsymia (7.5 mg phentermine / 46 mg topiramate), and in 9% of patients given the higher dose of Qsymia (15 mg phentermine / 92 mg topiramate) according to the prescribing information for the drug.

Altered taste or bad taste (dysgeusia) occurred in approximately 7% of subjects given the lower doses of Qsymia (7.5 mg phentermine / 46 mg topiramate), and in 9% of patients given the higher dose of Qsymia (15 mg phentermine / 92 mg topiramate) according to the prescribing information for the drug.

Cognitive disorders (problems with attention / concentration, memory, and language (word finding)) occurred in 7.6% of subjects given the higher dose of Qsymia (15 mg phentermine / 92 mg topiramate) versus 1.5% of people given a placebo according to the prescribing information for the drug.

Anxiety occurred in approximately 4% of subjects given the higher dose of Qsymia (15 mg phentermine / 92 mg topiramate) versus 2% of people given a placebo according to the prescribing information for the drug.

Depression occurred in approximately 4% of subjects given the higher dose of Qsymia (15 mg phentermine / 92 mg topiramate) versus 2% of people given a placebo according to the prescribing information for the drug.

Reduced sense of touch (hypoesthesia) occurred in approximately 4% of subjects given the lower doses of Qsymia (7.5 mg phentermine / 46 mg topiramate), and in 4% of patients given the higher dose of Qsymia (15 mg phentermine / 92 mg topiramate) according to the prescribing information for the drug.

Irritability occurred in approximately 3% of subjects given the lower doses of Qsymia (7.5 mg phentermine / 46 mg topiramate), and in 4% of patients given the higher dose of Qsymia (15 mg phentermine / 92 mg topiramate) according to the prescribing information for the drug.

Hair loss (alopecia) occurred in approximately 3% of subjects given the lower doses of Qsymia (7.5 mg phentermine / 46 mg topiramate), and in 4% of patients given the higher dose of Qsymia (15 mg phentermine / 92 mg topiramate) according to the prescribing information for the drug.

Disturbance in attention occurred in approximately 2% of subjects given the lower doses of Qsymia (7.5 mg phentermine / 46 mg topiramate), and in 4% of patients given the higher dose of Qsymia (15 mg phentermine / 92 mg topiramate) according to the prescribing information for the drug.

Low potassium levels (hypokalemia) occurred in 1.4% of subjects given the lower doses of Qsymia (7.5 mg phentermine / 46 mg topiramate), and in 2.5% of patients given the higher dose of Qsymia (15 mg phentermine / 92 mg topiramate) according to the prescribing information for the drug.

​Here are the dosage and administration instructions for Qsymia (phentermine / topirimate) as shown in the prescribing information.

In adults with an initial BMI of 30 kg/m2 or greater or 27 kg/m2 or greater when accompanied by weight-related co-morbidities such as hypertension, type 2 diabetes mellitus, or dyslipidemia prescribe Qsymia as follows: 

• Take Qsymia once daily in the morning with or without food. 
  
• Avoid dosing with Qsymia in the evening due to the possibility of insomnia.
  
• 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.
  
• Evaluate weight loss after 12 weeks of treatment with Qsymia 7.5 mg/46 mg.
  
• If a patient has not lost at least 3% of baseline body weight on Qsymia 7.5 mg/46 mg, discontinue Qsymia or escalate the dose, as it is unlikely that the patient will achieve and sustain clinically meaningful weight loss at the Qsymia 7.5 mg/46 mg dose.
  
• To escalate the dose: Increase to Qsymia 11.25 mg/69 mg (phentermine 11.25 mg/topiramate 69 mg extended-release) daily for 14 days; followed by dosing Qsymia 15 mg/92 mg (phentermine
  
• 15 mg/topiramate 92 mg extended-release) daily.
  
• Evaluate weight loss following dose escalation to Qsymia 15 mg/92 mg after an additional 12 weeks of treatment.
  
• If a patient has not lost at least 5% of baseline body weight on Qsymia 15 mg/92 mg, discontinue Qsymia as directed, as it is unlikely that the patient will achieve and sustain clinically meaningful weight loss with continued treatment.
  
• Qsymia 3.75 mg/23 mg and Qsymia 11.25 mg/69 mg are for titration purposes only.
  

Discontinuing Qsymia

• Discontinue Qsymia 15 mg/92 mg gradually by taking a dose 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.

​Here are the contraindications for Qsymia (phentermine / topirimate) as shown in the prescribing information.

• Pregnancy
  
• Glaucoma 
  
• Hyperthyroidism 
  
• During or within 14 days of taking monoamine oxidase inhibitors (MAO inhibitors) 
  
• Known hypersensitivity or idiosyncrasy to sympathomimetic amines

Here are the warnings and precautions for Qsymia (phentermine / topirimate) as shown in the prescribing information.

• Fetal Toxicity: Females of reproductive potential: Obtain negative pregnancy test before treatment and monthly thereafter; use effective contraception. 
• Qsymia is available through a limited program under a Risk Evaluation and Mitigation Strategy (REMS)
  
• Increase in Heart Rate: Monitor heart rate in all patients, especially those with cardiac or cerebrovascular disease.
  
• Suicidal Behavior and Ideation: Monitor for depression or suicidal thoughts. Discontinue Qysmia if symptoms develop.
  
• Acute Myopia and Secondary Angle Closure Glaucoma: Discontinue Qsymia.
  
• Mood and Sleep Disorders: Consider dose reduction or withdrawal for clinically significant or persistent symptoms.
  
• Cognitive Impairment: May cause disturbances in attention or  memory. 
  
• Caution patients about operating automobiles or hazardous machinery when starting treatment.
  
• Metabolic Acidosis: Measure electrolytes before/during treatment 
  
• Creatinine: Measure creatinine before/during treatment 
  
• Use of Antidiabetic Medications: Weight loss may cause hypoglycemia. 
  
• Measure serum glucose before/during treatment 
  

Here are the potential drug interactions for Qsymia (phentermine / topirimate) as shown in the prescribing information.

• Oral contraceptives: Altered exposure may cause irregular bleeding but not increased risk of pregnancy. 
  
• Advise patients not to discontinue oral contraceptives if spotting occurs.
  
• CNS depressants including alcohol: Potentiate CNS depressant effects. 
  
• Avoid concomitant use of alcohol
  
• Non-potassium sparing diuretics: May potentiate hypokalemia [low potassium].
  
• Measure potassium before/during treatment 
  

Here is information about Suicidal Behavior and Ideation regarding Qsymia (phentermine / topirimate) as shown in the prescribing information.

Suicidal Behavior and Ideation

Antiepileptic drugs (AEDs), including topiramate, a component of Qsymia, increase the risk of suicidal thoughts or behavior in patients taking these drugs for any indication. 

Patients treated with Qsymia should be monitored 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.

Avoid Qsymia in patients with a history of suicidal attempts or active suicidal ideation.

Here is information about the possibility of Myopia [nearsightedness] and glaucoma with the use of Qsymia (phentermine / topirimate) as shown in the prescribing information.

Acute Myopia [nearsightedness] and Secondary Angle Closure Glaucoma

A syndrome consisting of acute myopia [nearsightedness] associated with secondary angle closure glaucoma has been reported in patients treated with topiramate, a component of Qsymia. 

Symptoms include acute onset of decreased visual acuity and/or ocular pain.

Here is information about the possibility of anxiety, depression and insomnia with the use of Qsymia (phentermine / topirimate) as shown in the prescribing information.

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. 

The majority of these mood and sleep disorders resolved spontaneously, or resolved upon discontinuation of dosing [see Adverse Reactions].

Here is information about the possibility of Cognitive Impairment with the use of Qsymia (phentermine / topirimate) as shown in the prescribing information.

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].

Since Qsymia has the potential to impair cognitive function, patients should be cautioned about operating hazardous machinery, including automobiles, until they are reasonably certain Qsymia therapy does not affect them adversely.

If cognitive dysfunction persists consider dose reduction or withdrawal of Qsymia for symptoms that are moderate to severe, bothersome, or those which fail to resolve with dose reduction. 

Qsymia (phentermine and topiramate extended-release) was approved as a diet pill by the U.S. Food and Drug Administration on July 17, 2012 to be used in addition to a reduced-calorie diet and exercise for chronic weight management.

Qsymia (phentermine and topiramate extended-release) "must not be used during pregnancy because it can cause harm to a fetus," notes the press release from the U.S. Food and Drug Administration.

Subjects given the lower doses of Qsymia (7.5 mg phentermine plus 46 mg topiramate extended-release) lost 6.7% of their body weight more than those given a placebo.

Subjects given the higher doses of Qsymia (15 mg phentermine plus 92 mg topiramate extended-release) lost 8.9% of their body weight more than those given a placebo.

Subjects who don't lose at least 3% of their body weight after 3 months on the lower dose of Qsymia (7.5 mg phentermine plus 46 mg topiramate extended-release) are "unlikely to achieve and sustain weight loss with continued treatment at this dose," notes the press release from the U.S. FDA.

At this point, it should be evaluated based on weight loss if the drug should be discontinued or if the dose should be increased to the higher dose.

Qsymia must not be used in patients with glaucoma notes the press release from the U.S. FDA.

Qsymia must not be used in patients with hyperthyroidism notes the press release from the U.S. FDA.

Qsymia (phentermine plus topiramate) "can increase heart rate; this drug’s effect on heart rate in patients at high risk for heart attack or stroke" is not known notes the FDA press release.

• tingling of hands and feet (paresthesia)
• dizziness
• altered taste sensation
• insomnia
• constipation
• dry mouth

according to the FDA press release.

• paresthesia (tingling or pricking of a person's skin, a feeling of "pins and needles"


• dry mouth


• constipation


• altered taste (dysgeusia), and


• insomnia.

• Paraesthesia (tingling, pricking, or numbness of the skin) in 21% vs 14% vs 2%


• Dry Mouth in 21% vs 13% vs 2%


• Constipation in 17% vs 6% vs 5%


• Insomnia in 10% vs 7% vs 3%


• Dizziness in 10% vs 7% vs 3%


• Dysgeusia (altered taste) in 10% vs 7% vs 1%