Controlled Substance Schedule: IV
- Weight management as part of a program including caloric restriction and increased exercise in adults with an initial body mass index (BMI) of ≥30 kg/m2 or a BMI of ≥27 kg/m2 with ≥1 other risk factor (hypertension, type 2 diabetes mellitus, or dyslipidemia).
- Weight management as part of a program including caloric restriction and increased exercise in children ≥12 years old with an initial BMI in the 95th percentile or greater standardized for age and sex.
- Phentermine: ↓ appetite and food consumption;
- Topiramate: ↓ appetite and enhances satiety.
Absorption: Extent of absorption following oral administration unknown.
Metabolism and Excretion: Metabolized by the liver.
Half-life: 19–24 hr.
Absorption: 80% absorbed following oral administration.
Metabolism and Excretion: Not extensively metabolized. 70% excreted unchanged in urine.
Half-life: 21 hr.
TIME/ACTION PROFILE (weight loss)
|PO||within 8 wk||16–32 wk||unknown|
- Hypersensitivity/idiosyncracy to sympathomimetics (contains tartrazine);
- During/within 14 days of MAO inhibitors;
- End-stage renal disease on dialysis;
- Severe hepatic impairment;
- History of suicidal thought/active suicidal ideation;
- OB: Pregnancy;
- Lactation: Lactation.
Use Cautiously in:
- Diabetes (weight loss may ↑ risk of hypoglycemia);
- History of substance abuse;
- Ketogenic diet (↑ risk of kidney stones)
- Rep: Women of reproductive potential;
- Pedi: Children <12 yr (safety and effectiveness not established); may ↓ vertical growth;
- Geri: ↑ risk of adverse effects in older adults (consider age-related ↓ in cardiac, renal, and hepatic function, concurrent chronic disease states and medications).
Adverse Reactions/Side Effects
CV: tachycardia, hypotension, palpitations
Derm: alopecia, ERYTHEMA MULTIFORME, oligohydrosis (↓ sweating), STEVENS-JOHNSON SYNDROME, TOXIC EPIDERMAL NECROLYSIS
EENT: acute myopia, blurred vision, eye pain, secondary angle closure glaucoma, visual field defects
F and E: hypokalemia, metabolic acidosis
GI: altered taste, constipation, dry mouth, HEPATOTOXICITY
GU: ↑ serum creatinine, kidney stones
Metabolic: ↓ growth (children)
Neuro: headache, insomnia, paresthesia, cognitive impairment, dizziness, mood disorders, SEIZURES (FOLLOWING ABRUPT DISCONTINUATION), SUICIDAL IDEATION
Misc: ALLERGIC REACTION, hyperthermia
* CAPITALS indicate life-threatening.
Underline indicate most frequent.
- ↑ risk of hypokalemia with non-potassium sparing diuretics.
- ↑ risk of CNS depression with other CNS depressants including alcohol, some antihistamines, sedative/hypnotics, antipsychotics, and opioid analgesics ; avoid concurrent use of alcohol.
- Altered exposure to oral contraceptives may ↑ risk of irregular bleeding.
- Carbamazepine or phenytoin may ↓ levels.
- Concurrent use of topiramate with valproic acid may ↑ risk of hyperammonemia.
- Concurrent use of topiramate with carbonic anhydrase inhibitors may ↑ risk of metabolic acidosis and kidney stones.
- ↑ risk of hypotension with antihypertensive and diuretics.
- May ↓ pioglitazone levels.
PO (Adults): Phentermine 3.75 mg/topiramate 23 mg once daily for 14 days, then ↑ to phentermine 7.5 mg/topiramate 46 mg once daily for 12 wk, then assess weight loss. If patient has not lost at least 3% of baseline body weight, ↑ dose to phentermine 11.25 mg/topiramate 69 mg once daily for 14 days, then phentermine 15 mg/topiramate 92 mg once daily for 12 wk, then assess weight loss. If patient has not lost at least 5% of baseline body weight, discontinue therapy as success is unlikely. Discontinuation should proceed by taking the phentermine 15 mg/topiramate 92 mg capsule every other day for 1 wk and then discontinue therapy.
PO (Children ≥12 yr): Phentermine 3.75 mg/topiramate 23 mg once daily for 14 days, then ↑ to phentermine 7.5 mg/topiramate 46 mg once daily for 12 wk, then assess BMI. If patient has not experienced a reduction of at least 3% of baseline BMI, ↑ dose to phentermine 11.25 mg/topiramate 69 mg once daily for 14 days, then phentermine 15 mg/topiramate 92 mg once daily for 12 wk, then assess BMI. If patient has not experienced a reduction of at least 5% of baseline BMI, discontinue therapy as success is unlikely. Discontinuation should proceed by taking the phentermine 15 mg/topiramate 92 mg capsule every other day for 1 wk and then discontinue therapy. If weight loss exceeds 2 lb/wk, consider ↓ dose.
PO (Adults and Children ≥12 yr): CCr <50 mL/min: Not to exceed phentermine 7.5 mg/topiramate 46 mg once daily.
PO (Adults and Children): Moderate hepatic impairment: Not to exceed phentermine 7.5 mg/topiramate 46 mg once daily.
Capsules (contain tartrazine): phentermine 3.75 mg (immediate-release)/topiramate 23 mg (extended-release) (for titration only), phentermine 7.5 mg (immediate-release)/topiramate 46 mg (extended-release), phentermine 11.25 mg (immediate-release)/topiramate 69 mg (extended-release) (for titration only), phentermine 15 mg (immediate-release)/topiramate 92 mg (extended-release)
- Monitor patients for weight loss and adjust concurrent medications (antihypertensives, antidiabetics, lipid-lowering agents) as needed. Evaluate weight loss after each 12 wk of therapy.
Monitor closely for notable changes in behavior that could indicate the emergence or worsening of suicidal thoughts or behavior or depression. Discontinue phentermine/topiramate if these occur.
- Monitor BP and heart rate periodically during therapy; may cause increase in resting heart rate. May cause hypotension in patients treated with antihypertensives.
Lab Test Considerations:
Verify negative pregnancy test prior to starting therapy and monthly during therapy.
- Before starting and periodically during therapy with Qsymia , obtain a blood chemistry profile (serum bicarbonate, creatinine, and potassium) in all patients, and also blood glucose in patients with type 2 diabetes on antidiabetic medication.
- May cause hypoglycemia; monitor blood glucose closely in diabetic patients.
- May cause metabolic acidosis; monitor serum bicarbonate, prior to starting and periodically during therapy.
- May cause ↑ serum creatinine; peak increases observed after 4–8 wk of therapy. Monitor serum creatinine prior to and periodically during therapy; if persistent elevations occur, decrease dose or discontinue therapy.
- May cause hypokalemia; monitor serum potassium periodically during therapy.
- REMS: Qsymia is only available through certified pharmacies that are enrolled in the Qsymia certified pharmacy network. Information can be obtained at www.QsymiaREMS.com or by calling 1-888-998-4887.
- PO Administer once daily in the morning without regard to food. Avoid dosing in the evening; may cause insomnia.
- Instruct patient to take phentermine/topiramate as directed. Do not stop taking without consulting health care professional. Discontinue gradually taking 1 dose every other day for at least 1 wk before stopping to prevent seizures. REMS: Explain Qsymia REMS requirements to patient.
- Advise patient to notify health care professional if sustained periods of heart pounding or racing while at rest; severe and persistent eye pain or significant changes in vision; changes in attention, concentration, memory, and/or difficulty finding words; factors that can increase risk of acidosis (prolonged diarrhea, surgery, high-protein/low-carbohydrate diet, and/or concomitant medications).
Inform patients and families of risk of suicidal thoughts and behavior (behavioral changes, emerging or worsening signs and symptoms of depression, unusual changes in mood, or emergence of suicidal thoughts, behavior, or thoughts of self-harm). Advise that these should be reported to health care professional immediately.
- May cause changes in mental performance, motor performance, and/or vision. Caution patients to avoid driving and other activities requiring alertness until response to medication is known.
- Instruct patient to increase fluid intake to increase urinary output and decrease risk of kidney stones.
- Advise patient to monitor for decreased sweating and increased body temperature during physical activity, especially in hot weather.
- Instruct patient to notify health care professional of all Rx or OTC medications, vitamins, or herbal products being taken and consult health care professional before taking any new medications. Advise patient to avoid taking other CNS depressants, opioids, or alcohol.
- Rep: May cause fetal harm. Advise females of reproductive potential to use effective contraception and avoid breast feeding during therapy. Advise female patients to notify health care professional if pregnancy is planned or suspected. For patients taking combined oral contraceptives, may cause irregular bleeding and spotting; advise patient to continue oral contraceptive and notify health care professional if spotting is concerning. REMS: Because of teratogenic risk, Qsymia is only 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.
Decrease in weight and BMI.