Phentermn/topiramat 3.75-23mg ER CP
It is used to help with weight loss in certain people.
Drug Class
Weight Management Agent
Pharmacologic Class
Sympathomimetic Amine (Phentermine); Anticonvulsant, Carbonic Anhydrase Inhibitor (Topiramate)
Pregnancy Category
Category X
FDA Approved
Jul 2012
DEA Schedule
Schedule IV
Overview
What is this medicine?
Qsymia is a prescription medication that combines two drugs, phentermine and topiramate, in an extended-release capsule. It is used along with a reduced-calorie diet and increased physical activity to help adults and adolescents lose weight and keep it off. Phentermine helps reduce appetite, and topiramate helps you feel full and reduces cravings.
How to Use This Medicine
Taking Your Medication
To use this medication correctly, follow your doctor's instructions and read all the information provided. Take your medication as directed, with or without food. To minimize sleep disturbances, avoid taking this medication late in the day. Unless your doctor advises you to limit fluid intake, drink plenty of non-caffeinated liquids.
Storing and Disposing of Your Medication
Store your medication at room temperature in a dry location, avoiding the bathroom. Keep the container tightly closed.
Missing a Dose
If you miss a dose, skip it and resume your regular dosing schedule. Do not take two doses at the same time or take extra doses to make up for the missed one.
To use this medication correctly, follow your doctor's instructions and read all the information provided. Take your medication as directed, with or without food. To minimize sleep disturbances, avoid taking this medication late in the day. Unless your doctor advises you to limit fluid intake, drink plenty of non-caffeinated liquids.
Storing and Disposing of Your Medication
Store your medication at room temperature in a dry location, avoiding the bathroom. Keep the container tightly closed.
Missing a Dose
If you miss a dose, skip it and resume your regular dosing schedule. Do not take two doses at the same time or take extra doses to make up for the missed one.
Lifestyle & Tips
- Follow a reduced-calorie diet as prescribed by your healthcare provider.
- Increase your physical activity level gradually and consistently.
- Drink plenty of water to help prevent kidney stones and dry mouth.
- Avoid alcohol, as it can increase side effects like dizziness and drowsiness.
- Do not drive or operate machinery until you know how the medication affects you, as it can cause dizziness, vision problems, and impaired concentration.
- Females of reproductive potential must use effective contraception and have monthly pregnancy tests due to the risk of birth defects.
Available Forms & Alternatives
Dosing & Administration
Adult Dosing
Standard Dose:
Initial: 3.75 mg phentermine/23 mg topiramate ER orally once daily in the morning for 14 days. Titration: Increase to 7.5 mg phentermine/46 mg topiramate ER once daily. If inadequate weight loss after 12 weeks, may increase to 11.25 mg phentermine/69 mg topiramate ER for 14 days, then to 15 mg phentermine/92 mg topiramate ER. Discontinue if 5% weight loss not achieved after 12 weeks on highest dose.
Dose Range:
3.75 - 15 mg
Condition-Specific Dosing:
obesity:
For chronic weight management in adults with a BMI of 30 kg/m² or greater (obese) or 27 kg/m² or greater (overweight) with at least one weight-related comorbidity (e.g., hypertension, type 2 diabetes mellitus, dyslipidemia).
Pediatric Dosing
Neonatal:
Not established
Infant:
Not established
Child:
Not established
Adolescent:
Approved for adolescents 12 years and older with BMI at or above the 95th percentile for age and sex, or BMI at or above the 85th percentile for age and sex with at least one weight-related comorbidity. Dosing similar to adults, starting with 3.75 mg/23 mg ER once daily for 14 days, then increasing to 7.5 mg/46 mg ER once daily. Max dose 15 mg/92 mg ER once daily. Discontinue if 5% weight loss not achieved after 12 weeks on highest dose.
Dose Adjustments
Renal Impairment:
Mild:
No adjustment needed (CrCl 50-80 mL/min)
Moderate:
Max dose 7.5 mg phentermine/46 mg topiramate ER once daily (CrCl 30 to <50 mL/min)
Severe:
Not recommended (CrCl <30 mL/min)
Dialysis:
Not recommended
Hepatic Impairment:
Mild:
No adjustment needed (Child-Pugh A)
Moderate:
Max dose 7.5 mg phentermine/46 mg topiramate ER once daily (Child-Pugh B)
Severe:
Not recommended (Child-Pugh C)
Pharmacology
Mechanism of Action
Phentermine is a sympathomimetic amine that stimulates the release of norepinephrine from nerve terminals in the hypothalamus, resulting in appetite suppression. Topiramate's exact mechanism for weight loss is not fully understood but is thought to involve multiple actions, including appetite suppression and increased satiety, possibly through modulation of neurotransmitters (GABA potentiation, glutamate antagonism), carbonic anhydrase inhibition, and voltage-gated sodium channel blockade.
Pharmacokinetics
Absorption:
Bioavailability:
Phentermine: ~80-90%; Topiramate: ~81% (oral)
Tmax:
Phentermine: ~6-10 hours (ER); Topiramate: ~9 hours (ER)
FoodEffect:
Food does not significantly affect the absorption of phentermine or topiramate ER, but high-fat meals may delay Tmax for topiramate.
Distribution:
Vd:
Phentermine: ~3.7 L/kg; Topiramate: ~0.6-0.8 L/kg
ProteinBinding:
Phentermine: ~17%; Topiramate: ~9-17%
CnssPenetration:
Yes (both components cross the blood-brain barrier)
Elimination:
HalfLife:
Phentermine: ~20-24 hours; Topiramate: ~20-30 hours
Clearance:
Phentermine: Primarily renal; Topiramate: Primarily renal
ExcretionRoute:
Renal (unchanged drug)
Unchanged:
Phentermine: ~60-80%; Topiramate: ~70%
Pharmacodynamics
OnsetOfAction:
Within hours (phentermine); Gradual (topiramate)
PeakEffect:
Phentermine: 6-10 hours; Topiramate: 9 hours
DurationOfAction:
24 hours (due to ER formulation and long half-lives)
Safety & Warnings
BLACK BOX WARNING
Qsymia can cause fetal harm. Females of reproductive potential should have a negative pregnancy test before starting Qsymia and monthly thereafter, and use effective contraception during Qsymia treatment. If pregnancy occurs, Qsymia should be discontinued immediately. Qsymia is available only through a restricted program called the Qsymia REMS program.
Side Effects
Urgent Side Effects: Seek Medical Help Right Away
Although rare, some people may experience severe and potentially life-threatening side effects when taking this medication. If you experience any of the following symptoms, contact your doctor or seek medical help immediately:
Signs of an allergic reaction, such as:
+ Rash
+ Hives
+ Itching
+ Red, swollen, blistered, or peeling skin with or without fever
+ Wheezing
+ Tightness in the chest or throat
+ Trouble breathing, swallowing, or talking
+ Unusual hoarseness
+ Swelling of the mouth, face, lips, tongue, or throat
Signs of acidosis (too much acid in the blood), such as:
+ Confusion
+ Fast breathing
+ Fast heartbeat
+ Irregular heartbeat
+ Severe stomach pain, nausea, or vomiting
+ Excessive sleepiness
+ Shortness of breath
+ Feeling extremely tired or weak
Signs of low potassium levels, such as:
+ Muscle pain or weakness
+ Muscle cramps
+ Irregular heartbeat
Signs of a urinary tract infection (UTI), such as:
+ Blood in the urine
+ Burning or pain when urinating
+ Frequent or urgent need to urinate
+ Fever
+ Lower abdominal pain or pelvic pain
Abnormal or rapid heartbeat
Confusion, difficulty focusing, or changes in behavior
Memory problems or loss
Speech difficulties
Sleep disturbances
Urination problems, such as inability to urinate or changes in urine output
Back pain, abdominal pain, or blood in the urine, which may indicate a kidney stone
Patients taking this medication may be at a higher risk of suicidal thoughts or actions, especially if they have a history of such thoughts or actions. If you experience new or worsening symptoms such as depression, anxiety, restlessness, irritability, panic attacks, or mood changes, contact your doctor immediately. If you have suicidal thoughts or actions, seek help right away.
This medication may cause severe eye problems, potentially leading to permanent vision loss if left untreated. If you experience new eye symptoms, such as blurred vision, changes in vision, eye pain, or eye redness, contact your doctor immediately.
A severe skin reaction (Stevens-Johnson syndrome/toxic epidermal necrolysis) may occur, which can cause serious health problems and even death. Seek medical help immediately if you experience:
+ Red, swollen, blistered, or peeling skin (with or without fever)
+ Red or irritated eyes
+ Sores in your mouth, throat, nose, or eyes
Other Possible Side Effects
Most medications can cause side effects, but many people experience none or only mild symptoms. If you experience any of the following side effects or any other symptoms that bother you or do not go away, contact your doctor or seek medical help:
Headache
Diarrhea or constipation
Dry mouth
Numbness or tingling
Dizziness, fatigue, or weakness
Changes in taste
Nausea or stomach upset
Common cold symptoms
Nose or throat irritation
Back pain
* Joint pain
This is not an exhaustive list of possible side effects. If you have questions or concerns about side effects, contact your doctor. You can also report side effects to the FDA at 1-800-332-1088 or online at https://www.fda.gov/medwatch.
Although rare, some people may experience severe and potentially life-threatening side effects when taking this medication. If you experience any of the following symptoms, contact your doctor or seek medical help immediately:
Signs of an allergic reaction, such as:
+ Rash
+ Hives
+ Itching
+ Red, swollen, blistered, or peeling skin with or without fever
+ Wheezing
+ Tightness in the chest or throat
+ Trouble breathing, swallowing, or talking
+ Unusual hoarseness
+ Swelling of the mouth, face, lips, tongue, or throat
Signs of acidosis (too much acid in the blood), such as:
+ Confusion
+ Fast breathing
+ Fast heartbeat
+ Irregular heartbeat
+ Severe stomach pain, nausea, or vomiting
+ Excessive sleepiness
+ Shortness of breath
+ Feeling extremely tired or weak
Signs of low potassium levels, such as:
+ Muscle pain or weakness
+ Muscle cramps
+ Irregular heartbeat
Signs of a urinary tract infection (UTI), such as:
+ Blood in the urine
+ Burning or pain when urinating
+ Frequent or urgent need to urinate
+ Fever
+ Lower abdominal pain or pelvic pain
Abnormal or rapid heartbeat
Confusion, difficulty focusing, or changes in behavior
Memory problems or loss
Speech difficulties
Sleep disturbances
Urination problems, such as inability to urinate or changes in urine output
Back pain, abdominal pain, or blood in the urine, which may indicate a kidney stone
Patients taking this medication may be at a higher risk of suicidal thoughts or actions, especially if they have a history of such thoughts or actions. If you experience new or worsening symptoms such as depression, anxiety, restlessness, irritability, panic attacks, or mood changes, contact your doctor immediately. If you have suicidal thoughts or actions, seek help right away.
This medication may cause severe eye problems, potentially leading to permanent vision loss if left untreated. If you experience new eye symptoms, such as blurred vision, changes in vision, eye pain, or eye redness, contact your doctor immediately.
A severe skin reaction (Stevens-Johnson syndrome/toxic epidermal necrolysis) may occur, which can cause serious health problems and even death. Seek medical help immediately if you experience:
+ Red, swollen, blistered, or peeling skin (with or without fever)
+ Red or irritated eyes
+ Sores in your mouth, throat, nose, or eyes
Other Possible Side Effects
Most medications can cause side effects, but many people experience none or only mild symptoms. If you experience any of the following side effects or any other symptoms that bother you or do not go away, contact your doctor or seek medical help:
Headache
Diarrhea or constipation
Dry mouth
Numbness or tingling
Dizziness, fatigue, or weakness
Changes in taste
Nausea or stomach upset
Common cold symptoms
Nose or throat irritation
Back pain
* Joint pain
This is not an exhaustive list of possible side effects. If you have questions or concerns about side effects, contact your doctor. You can also report side effects to the FDA at 1-800-332-1088 or online at https://www.fda.gov/medwatch.
Seek Immediate Medical Attention If You Experience:
- Sudden, severe eye pain or vision changes (e.g., blurred vision, decreased vision)
- Signs of metabolic acidosis (e.g., persistent fatigue, loss of appetite, fast breathing, irregular heartbeat)
- New or worsening depression, anxiety, or thoughts of self-harm
- Significant increase in blood pressure or heart rate
- Chest pain, shortness of breath, or fainting
- Signs of kidney stones (e.g., severe back or side pain, blood in urine, painful urination)
- Confusion, memory problems, or difficulty concentrating
- Tingling or numbness in hands or feet
- Fever, chills, or sore throat (signs of infection, especially if also experiencing fatigue and confusion, which could indicate hyperammonemia)
Before Using This Medicine
Before Taking This Medication: Important Information to Share with Your Doctor
It is essential to inform your doctor about the following conditions and situations to ensure safe treatment:
Any allergies you have, including allergies to this medication, its components, or other substances, such as foods or drugs. Describe the allergic reaction and its symptoms.
Certain health conditions, including:
+ Glaucoma
+ Overactive thyroid disease
+ Depression or a history of suicidal thoughts
+ Kidney disease
+ Liver disease
Concurrent use of specific medications, such as:
+ Acetazolamide, dichlorphenamide, methazolamide, or zonisamide
+ Certain antidepressants or Parkinson's disease medications taken within the last 14 days, including isocarboxazid, phenelzine, tranylcypromine, selegiline, or rasagiline, as they may cause very high blood pressure
+ Linezolid or methylene blue
Pregnancy or potential pregnancy, as this medication is contraindicated during pregnancy
Breast-feeding, as you should not breast-feed while taking this medication
The patient's age, as this medication is not approved for children under 12 years of age
To ensure your safety, it is crucial to provide your doctor and pharmacist with a comprehensive list of:
All prescription and over-the-counter medications you are taking
Natural products and vitamins you are using
* Your health problems, including any medical conditions or allergies
Do not start, stop, or change the dose of any medication without consulting your doctor to verify that it is safe to take this medication with your other medications and health conditions.
It is essential to inform your doctor about the following conditions and situations to ensure safe treatment:
Any allergies you have, including allergies to this medication, its components, or other substances, such as foods or drugs. Describe the allergic reaction and its symptoms.
Certain health conditions, including:
+ Glaucoma
+ Overactive thyroid disease
+ Depression or a history of suicidal thoughts
+ Kidney disease
+ Liver disease
Concurrent use of specific medications, such as:
+ Acetazolamide, dichlorphenamide, methazolamide, or zonisamide
+ Certain antidepressants or Parkinson's disease medications taken within the last 14 days, including isocarboxazid, phenelzine, tranylcypromine, selegiline, or rasagiline, as they may cause very high blood pressure
+ Linezolid or methylene blue
Pregnancy or potential pregnancy, as this medication is contraindicated during pregnancy
Breast-feeding, as you should not breast-feed while taking this medication
The patient's age, as this medication is not approved for children under 12 years of age
To ensure your safety, it is crucial to provide your doctor and pharmacist with a comprehensive list of:
All prescription and over-the-counter medications you are taking
Natural products and vitamins you are using
* Your health problems, including any medical conditions or allergies
Do not start, stop, or change the dose of any medication without consulting your doctor to verify that it is safe to take this medication with your other medications and health conditions.
Precautions & Cautions
Important Warnings and Cautions
It is essential to inform all your healthcare providers, including doctors, nurses, pharmacists, and dentists, that you are taking this medication.
Caution with Daily Activities
Avoid driving and engaging in activities that require alertness until you understand how this medication affects you.
Monitoring and Follow-Up
Regularly have your blood work, blood pressure, and heart rate checked as directed by your doctor. Additionally, follow the diet and exercise plan recommended by your doctor.
Stopping the Medication
Do not suddenly stop taking this medication without consulting your doctor, as this may increase your risk of seizures. If you need to stop taking this medication, your doctor will guide you on how to gradually discontinue it.
Interactions with Other Substances
Before consuming alcohol, marijuana, or other forms of cannabis, or taking prescription or over-the-counter medications that may cause drowsiness, discuss the potential risks with your doctor.
Special Considerations for Diabetes and High Blood Pressure
If you have diabetes and take medications to lower your blood sugar, consult your doctor, as weight loss may increase your risk of low blood sugar. Be aware of the signs of low blood sugar, such as dizziness, headache, fatigue, weakness, shaking, rapid heartbeat, confusion, hunger, or sweating, and seek medical attention immediately if you experience any of these symptoms.
Similarly, if you are being treated for high blood pressure, inform your doctor, as weight loss may increase your risk of low blood pressure. Seek medical attention immediately if you experience severe dizziness or fainting.
Risk of Metabolic Acidosis
This medication may cause a condition called metabolic acidosis, which can be more likely in children, people with kidney problems, breathing difficulties, or diarrhea. The risk may also be higher if you take certain medications, undergo surgery, or follow a ketogenic diet. Over time, metabolic acidosis can lead to kidney stones, bone problems, or growth issues in children.
Allergic Reactions
If you are allergic to tartrazine (FD&C Yellow No. 5), inform your doctor, as some products contain this ingredient.
Heat-Related Risks
Be cautious in hot weather and during physical activity, as this medication can cause decreased sweating and increased body temperature, which may lead to hospitalization. Seek medical attention immediately if you experience a fever or decreased sweating during activities or in warm temperatures.
Effects on Growth and Menstrual Cycle
This medication may affect growth in children and teenagers, and regular growth checks may be necessary. Additionally, if you take birth control, your menstrual bleeding may change while taking this medication. Inform your doctor if you experience any changes.
Pregnancy and Birth Control
A pregnancy test will be conducted before starting this medication and during treatment to ensure you are not pregnant. The risk of birth defects is higher if this medication is taken during pregnancy, and the baby may be smaller at birth. It is unknown whether this leads to long-term problems. If you may become pregnant, you must use birth control while taking this medication. If you become pregnant, inform your doctor immediately.
It is essential to inform all your healthcare providers, including doctors, nurses, pharmacists, and dentists, that you are taking this medication.
Caution with Daily Activities
Avoid driving and engaging in activities that require alertness until you understand how this medication affects you.
Monitoring and Follow-Up
Regularly have your blood work, blood pressure, and heart rate checked as directed by your doctor. Additionally, follow the diet and exercise plan recommended by your doctor.
Stopping the Medication
Do not suddenly stop taking this medication without consulting your doctor, as this may increase your risk of seizures. If you need to stop taking this medication, your doctor will guide you on how to gradually discontinue it.
Interactions with Other Substances
Before consuming alcohol, marijuana, or other forms of cannabis, or taking prescription or over-the-counter medications that may cause drowsiness, discuss the potential risks with your doctor.
Special Considerations for Diabetes and High Blood Pressure
If you have diabetes and take medications to lower your blood sugar, consult your doctor, as weight loss may increase your risk of low blood sugar. Be aware of the signs of low blood sugar, such as dizziness, headache, fatigue, weakness, shaking, rapid heartbeat, confusion, hunger, or sweating, and seek medical attention immediately if you experience any of these symptoms.
Similarly, if you are being treated for high blood pressure, inform your doctor, as weight loss may increase your risk of low blood pressure. Seek medical attention immediately if you experience severe dizziness or fainting.
Risk of Metabolic Acidosis
This medication may cause a condition called metabolic acidosis, which can be more likely in children, people with kidney problems, breathing difficulties, or diarrhea. The risk may also be higher if you take certain medications, undergo surgery, or follow a ketogenic diet. Over time, metabolic acidosis can lead to kidney stones, bone problems, or growth issues in children.
Allergic Reactions
If you are allergic to tartrazine (FD&C Yellow No. 5), inform your doctor, as some products contain this ingredient.
Heat-Related Risks
Be cautious in hot weather and during physical activity, as this medication can cause decreased sweating and increased body temperature, which may lead to hospitalization. Seek medical attention immediately if you experience a fever or decreased sweating during activities or in warm temperatures.
Effects on Growth and Menstrual Cycle
This medication may affect growth in children and teenagers, and regular growth checks may be necessary. Additionally, if you take birth control, your menstrual bleeding may change while taking this medication. Inform your doctor if you experience any changes.
Pregnancy and Birth Control
A pregnancy test will be conducted before starting this medication and during treatment to ensure you are not pregnant. The risk of birth defects is higher if this medication is taken during pregnancy, and the baby may be smaller at birth. It is unknown whether this leads to long-term problems. If you may become pregnant, you must use birth control while taking this medication. If you become pregnant, inform your doctor immediately.
Overdose Information
Overdose Symptoms:
- Phentermine overdose: Restlessness, tremor, rapid breathing, confusion, hallucinations, panic states, high fever, muscle pain/weakness, seizures, coma, irregular heartbeats, high or low blood pressure, nausea, vomiting, diarrhea, abdominal cramps.
- Topiramate overdose: Convulsions, drowsiness, speech disturbance, blurred vision, double vision, impaired coordination, lethargy, depression, abdominal pain, dizziness, metabolic acidosis, hypokalemia, hypotension.
What to Do:
Seek immediate medical attention. Call 911 or Poison Control at 1-800-222-1222. Management is primarily supportive, including gastric lavage, activated charcoal, and maintaining airway/cardiovascular function. Hemodialysis is effective for topiramate removal.
Drug Interactions
Contraindicated Interactions
- Monoamine Oxidase Inhibitors (MAOIs) - concurrent use or within 14 days of MAOI discontinuation (risk of hypertensive crisis)
- Glaucoma (narrow angle)
- Hyperthyroidism
- Advanced arteriosclerosis
- Symptomatic cardiovascular disease (e.g., uncontrolled hypertension, congestive heart failure, stroke, arrhythmia)
- History of drug abuse
- Pregnancy
Major Interactions
- Other CNS depressants (e.g., alcohol, benzodiazepines, opioids) - increased CNS depression
- Oral Contraceptives - topiramate may decrease efficacy (consider alternative or additional birth control)
- Carbonic Anhydrase Inhibitors (e.g., zonisamide, acetazolamide, dichlorphenamide) - increased risk of metabolic acidosis and kidney stones
- Valproic Acid - increased risk of hyperammonemia with or without encephalopathy
- Metformin - topiramate may increase metformin levels (monitor for lactic acidosis)
- Non-potassium-sparing diuretics (e.g., hydrochlorothiazide) - increased risk of hypokalemia and metabolic acidosis
- Antidepressants (e.g., SSRIs, SNRIs, TCAs) - potential for serotonin syndrome or increased phentermine effects
- Insulin and/or oral hypoglycemic agents - dose adjustments may be needed as weight loss improves glycemic control
Moderate Interactions
- CNS stimulants (e.g., ADHD medications) - additive stimulant effects
- Digoxin - topiramate may decrease digoxin levels
- Lithium - topiramate may alter lithium levels
- Phenytoin - topiramate may alter phenytoin levels
- Carbamazepine - topiramate may alter carbamazepine levels
Minor Interactions
- Not available (most interactions are moderate to major due to the nature of the active ingredients)
Monitoring
Baseline Monitoring
Pregnancy Test
Rationale: Qsymia is contraindicated in pregnancy due to teratogenicity (Category X).
Timing: Prior to initiation in females of reproductive potential.
Blood Pressure (BP) and Heart Rate (HR)
Rationale: Phentermine can increase BP and HR. Topiramate can also cause bradycardia.
Timing: Prior to initiation.
Serum Electrolytes (Bicarbonate, Potassium)
Rationale: Topiramate can cause metabolic acidosis and hypokalemia.
Timing: Prior to initiation.
Renal Function (CrCl)
Rationale: Dose adjustment required for renal impairment; drug is renally cleared.
Timing: Prior to initiation.
Mental Status/Psychiatric History
Rationale: Topiramate can increase risk of mood disturbances, depression, and suicidal ideation.
Timing: Prior to initiation.
Eye Exam (for glaucoma history)
Rationale: Topiramate can cause acute myopia and secondary angle-closure glaucoma.
Timing: Prior to initiation, especially if history of glaucoma.
Routine Monitoring
Pregnancy Test
Frequency: Monthly
Target: Negative
Action Threshold: Discontinue immediately if positive.
Blood Pressure (BP) and Heart Rate (HR)
Frequency: Regularly (e.g., monthly for first few months, then every 3-6 months)
Target: Within normal limits or patient's target BP/HR
Action Threshold: Persistent clinically significant increases (e.g., >10 mmHg increase in BP, >10 bpm increase in HR) may warrant dose reduction or discontinuation.
Serum Bicarbonate
Frequency: Periodically (e.g., every 3-6 months or as clinically indicated)
Target: Normal range (22-29 mEq/L)
Action Threshold: Persistent decreases below normal range may require dose reduction or discontinuation.
Weight Loss
Frequency: Every 4-12 weeks
Target: At least 3% weight loss after 12 weeks on initial dose, 5% after 12 weeks on higher doses.
Action Threshold: If inadequate weight loss, consider dose escalation or discontinuation.
Mental Status/Mood
Frequency: Ongoing assessment at each visit
Target: Stable mood, no new or worsening psychiatric symptoms
Action Threshold: New or worsening depression, suicidal thoughts, or other mood/behavioral changes require immediate evaluation and potential discontinuation.
Kidney Stone Symptoms
Frequency: Ongoing assessment
Target: Absence of symptoms
Action Threshold: Flank pain, hematuria, or other symptoms warrant investigation.
Symptom Monitoring
- Increased heart rate or blood pressure
- Palpitations
- Shortness of breath
- Chest pain
- Dizziness or lightheadedness
- Mood changes (depression, anxiety, irritability)
- Suicidal thoughts or behavior
- Difficulty concentrating or memory problems (cognitive impairment)
- Tingling or numbness in hands/feet (paresthesia)
- Dry mouth
- Constipation
- Insomnia
- Kidney stone symptoms (flank pain, blood in urine, painful urination)
- Vision changes (sudden decrease in vision, eye pain)
- Signs of metabolic acidosis (fatigue, loss of appetite, irregular heartbeat)
Special Patient Groups
Pregnancy
CONTRAINDICATED. Qsymia can cause fetal harm (oral clefts, hypospadias, and other congenital malformations). Females of reproductive potential must use effective contraception and have monthly pregnancy tests. Qsymia is available only through a restricted program (REMS).
Trimester-Specific Risks:
First Trimester:
Highest risk for major congenital malformations, particularly oral clefts and hypospadias, due to topiramate exposure.
Second Trimester:
Not applicable, as drug should be discontinued immediately upon pregnancy detection.
Third Trimester:
Not applicable, as drug should be discontinued immediately upon pregnancy detection.
Lactation
Not recommended. Both phentermine and topiramate are excreted in human milk. Potential for serious adverse reactions in the breastfed infant (e.g., irritability, poor feeding, sedation, weight loss, metabolic acidosis).
Infant Risk:
L3-L4 (Moderate to High Risk). Monitor infant for irritability, poor feeding, sedation, weight loss, and signs of metabolic acidosis.
Pediatric Use
Approved for adolescents 12 years and older with obesity (BMI ≥95th percentile for age/sex) or overweight (BMI ≥85th percentile for age/sex) with weight-related comorbidity. Safety and effectiveness in pediatric patients younger than 12 years have not been established.
Geriatric Use
Use with caution in elderly patients (≥65 years) due to increased likelihood of decreased renal function and potential for increased sensitivity to side effects. Start at the lower end of the dosing range and monitor renal function closely. Max dose 7.5 mg phentermine/46 mg topiramate ER once daily if CrCl <50 mL/min.
Clinical Information
Clinical Pearls
- Qsymia is part of a REMS program due to its teratogenic risk; prescribers and pharmacies must be certified, and patients must be enrolled.
- Titrate dose slowly to minimize side effects and improve tolerability.
- Monitor blood pressure and heart rate closely, especially during dose escalation. Discontinue if sustained clinically significant increases occur.
- Counsel patients on the importance of adequate hydration to reduce the risk of kidney stones.
- Be vigilant for psychiatric side effects, including depression and suicidal ideation, especially in patients with a history of mood disorders.
- Advise females of reproductive potential about the absolute necessity of effective contraception and monthly pregnancy testing.
- Discontinue treatment gradually to avoid potential withdrawal symptoms (e.g., seizures if patient has a history of epilepsy, or rebound appetite/weight gain).
Alternative Therapies
- Liraglutide (Saxenda, Victoza)
- Semaglutide (Wegovy, Ozempic)
- Orlistat (Xenical, Alli)
- Phentermine (Adipex-P, Lomaira)
- Setmelanotide (Imcivree - for specific genetic conditions)
Cost & Coverage
Average Cost:
$180 - $250 per 30 capsules
Insurance Coverage:
Tier 3 (Non-preferred Brand) or Tier 2 (Preferred Brand) depending on insurance plan. Often requires prior authorization and/or step therapy.
General Drug Facts
If your symptoms or health issues persist or worsen, it is essential to contact your doctor promptly. To ensure safe use, never share your medication with others or take someone else's medication. This medication is accompanied by a Medication Guide, a patient fact sheet that provides crucial information. Please read this guide carefully and review it again whenever you receive a refill of this medication. If you have any questions or concerns about this medication, we encourage you to discuss them with your doctor, pharmacist, or other healthcare provider. In the event of a suspected overdose, immediately call your local poison control center or seek emergency medical attention. When reporting the incident, be prepared to provide details about the medication taken, the amount, and the time it occurred.