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How Does Qsymia Work for Weight Loss

Weight loss prescription Qsymia
Written by:

Rabia Khaliq

MSc in Applied Psychology


Medical Disclaimer
The medications listed on this website are provided for informational purposes only. Their inclusion does not guarantee that they will be prescribed to any individual, as treatment decisions are ultimately at the discretion of healthcare providers. This list is not exhaustive, and healthcare providers may prescribe other medications, including non-stimulant options, based on the patient’s unique health circumstances and needs. Read more

Getting rid of excess weight is tough, and keeping it off is even more challenging. Did you know that only about 20% of Americans [1*] who lose weight can keep it off for the long haul? It might feel discouraging. However, for those who tried everything and still haven’t achieved their weight loss goals, there are specific pharmacological solutions. For example, a weight loss prescription medication Qsymia. It is not just a weight loss helper but a tool that assists you in sticking with your progress. 

Let’s dive into a brief guide to learn how Qsymia works and how it can contribute to long-lasting weight management success.

Ready to take the next step? Connect with our healthcare providers via telehealth to explore the possibilities with Qsymia today.

What Is Qsymia (Phentermine-Topiramate ER)?

Qsymia makes your brain’s chemical messenger GABA (gamma-aminobutyric acid) more active. This can curb your appetite and make you feel full. As a side effect, it can change how some foods taste. This weight loss medication starts working right after you take it and is meant to be used with a reduced-calorie diet and regular exercise to support its effects.

When Is Qsymia Prescribed?

Qsymia is designed for chronic weight management, specifically for those dealing with overweight issues or obesity-related complications. It comprises a phentermine-topiramate blend enclosed in an extended-release capsule.

While topiramate was initially developed to treat epilepsy, it has also been found to have other effects, including appetite restraint, making it a component of medications like Qsymia for weight management. Today, phentermine [2*] is prescribed as an appetite suppressant. 

Qsymia is prescribed alongside a reduced-calorie diet and regular exercise to assist obese and overweight adults and adolescents aged 12 and above in managing their weight. It is also recommended for adults with excess weight facing weight-related health issues like diabetes, high cholesterol, or high blood pressure.

Side Effects of Qsymia

Aside from its intended positive effects, Qsymia may cause adverse reactions in some people. While not everyone may experience these side effects, it’s pivotal to seek medical attention if they do manifest:

  • Numbness or tingling in hands, arms, feet, or face
  • Dizziness
  • Lightheadedness
  • Difficulty sleeping
  • Constipation
  • Dry mouth
  • Trouble focusing

Possible serious side effects of Qsymia include:

  • Suicidal thoughts or actions caused by topiramate, a component of Qsymia.
  • Severe eye problems, including sudden vision decreases.
  • Heightened risk of kidney stones.
  • Increased acid levels in the bloodstream.
  • Cardiac arrhythmia or a racing heart.
  • Low blood sugar (hypoglycemia) in people with type 2 diabetes who also use medications for diabetes (such as insulin or sulfonylureas).
Reach out to our medical providers to learn about possible side effects of Qsymia in advance and get ongoing guidance and support.

Pros And Cons of Qsymia



Once-a-day dosage for convenience.

Not safe for use during pregnancy.

Combination of two medications in a single pill.

Classified as a controlled substance, accessible only through a REMS (Risk Evaluation and Mitigation Strategy) program.

Losing weight can help prevent, manage, and occasionally reverse health problems associated with obesity.

Potentially increases the risk of depression or self-harm ideation and has an extended list of side effects, warnings, and precautions.

Available for children aged 12 and older when strict prerequisites for such treatment are met.

May interact with other medications, including birth control pills, certain seizure medications, etc.

How to Take Qsymia: General Information

Qsymia is recommended to be taken orally once daily, with or without food. To avoid potential insomnia, it is preferable to take Qsymia in the morning rather than close to bedtime. However, remember to get personalized instructions from your healthcare provider.

Dosing Information

Qsymia can be prescribed to adults with a body mass index (BMI) of 30 or higher. Additionally, eligibility extends to individuals with a BMI of at least 27 who have one or more weight-related health conditions, such as high blood pressure, type 2 diabetes, or high cholesterol.

The Qsymia dosage for weight loss in adults is generally ranging from 3.75 mg phentermine/23 mg topiramate to 15 mg phentermine/92 mg topiramate. It’s typical to begin with a lower dosage and monitor the weight loss progress to understand whether an increase in dosage is required or not. Typically, the milestone where this decision is made is 12 weeks after starting Qsymia.

Qsymia Dosage Schedule for Adults: General Outline

  1. Starting dosage: Qsymia 3.75 mg/23 mg orally once daily for the initial 14 days.
  2. After the initial 14 days: The dosage can be increased to 7.5 mg/46 mg orally once daily.
  3. After 12 weeks from the beginning of treatment: A patient goes through a weight loss assessment. If an adult has not achieved at least a 3% reduction in baseline body weight, the dosage is increased.
  4. Further adjustment, if needed: A healthcare provider may recommend an increase in dosage to Qsymia 11.25 mg/69 mg for 14 days, followed by an increase to Qsymia 15 mg/92 mg orally once daily. Note that only a healthcare provider can decide on the dosage raise, so never adjust your treatment without consulting a clinician.
  5. After the additional 12 weeks: A patient goes through a weight loss assessment. If an adult has not achieved at least a 5% reduction in baseline body weight (the edge for clinically meaningful weight loss), discontinuation may be considered.

Important to note: If your healthcare provider advises discontinuing Qsymia, a gradual reduction in the dose is typically recommended so as to minimize withdrawal effects. Your clinician should guide you through a safe cessation process, which usually involves taking a capsule every other day for one week before stopping altogether.

Sudden stopping of Qsymia has been linked to seizures even in patients without a history of seizures or epilepsy. If an urgent discontinuation of Qsymia is necessary, close monitoring is advised.

Seek guidance from experts at MEDvidi for personalized recommendations on weight loss. Receive an online Qsymia prescription if deemed necessary.

What Happens If I Miss a Dose?

If you miss a dose, skip it for the day and resume the regular schedule the following day. Avoid taking additional doses or doubling up to compensate for the missed dose because it is unsafe.

What Happens if I Overdose?

In case of overdose, seek prompt medical attention. Symptoms may encompass confusion, drowsiness, and tremors. More severe manifestations include hallucinations, coma, and potential fatality. 

Warnings and Precautions

Before embarking upon a course of Qsymia for weight management, it is imperative to know some critical warnings and precautions. Understanding these points enables the safe integration of this medication into your wellness regimen. Let’s take a quick look at the following pivotal considerations.

Embryo-Fetal Risk

Qsymia may harm the fetus, increasing the risk of oral clefts. A negative pregnancy test is advised before starting and monthly during treatment. Women of childbearing age should be aware of fetal risks and use effective contraception during Qsymia therapy.

Increased Heart Rate

Qsymia may elevate the resting heart rate. A larger proportion of adults and pediatric patients treated with Qsymia (aged 12 years and older) experienced increases in heart rate. Regularly check your resting heart rate, especially if you have heart conditions. 

Risk of Suicidal Behavior and Ideation

Antiepileptic drugs (AEDs), including topiramate [3*] , heighten the risk of suicidal thoughts or behavior. Monitor yourself for signs of depression and unusual mood changes and discuss these symptoms with your clinician before starting Qsymia therapy.

Eye-Related Issues

Topiramate use may lead to a condition characterized by sudden myopia and secondary angle closure glaucoma. Symptoms include rapid loss of vision and/or eye pain. If untreated, it may cause serious complications, including permanent vision loss.

Mood and Sleep Сoncerns

Qsymia may induce mood disorders such as depression and anxiety, along with insomnia. If you have a history of depression, you may face a higher risk of recurring depression or other mood disorders while using Qsymia.

Linear Growth Speed Decrease

Qsymia is linked to a decrease in the speed of linear growth (centimeters gained in height per year) in obese child patients aged 12 to 17 years. It’s recommended to regularly assess height velocity in child patients undergoing Qsymia treatment.

Hypoglycemia Risk

For people with type 2 diabetes using insulin or insulin secretagogues (like sulfonylureas), weight loss with Qsymia may heighten the risk of low blood sugar (hypoglycemia). Check blood glucose levels before and during Qsymia treatment. 

Low Blood Pressure

For those with hypertension using antihypertensive medications, weight loss with Qsymia may raise the risk of low blood pressure and related symptoms. Monitor blood pressure regularly while on Qsymia. 

Acidosis Risk

Qsymia use may lead to metabolic acidosis, displaying symptoms like hyperventilation and fatigue. Chronic acidosis may increase the risk of kidney issues and bone conditions and hinder growth in young patients.

Severe Skin Reactions

Serious skin reactions have been reported with topiramate use. If there are such indications, do not resume this medication and explore alternative therapies during a consultation with your healthcare provider. 

Decreased Sweating & Elevated Body Temperature

Topiramate use has been linked to oligohidrosis (reduced sweating), occasionally leading to hospitalization. These cases were characterized by decreased sweating and an elevated body temperature, often occurring in high-temperature environments. Watch for reduced sweating and higher body temperature, especially during physical activity in hot weather. 

Cognitive Problems

Qsymia may lead to cognitive issues with concentration, memory, and speech. Swift titration or high initial doses may increase this risk for such problems. Exercise caution when operating machinery, including automobiles, until you are reasonably sure Qsymia therapy does not adversely affect them. 


Qsymia may raise the risk of low potassium levels by inhibiting carbonic anhydrase activity. Using Qsymia with non-potassium-sparing diuretics can further enhance potassium loss. Check potassium levels before and during your treatment. 

Renal Function Concerns

Qsymia may increase serum creatinine, suggesting a possible decrease in kidney function. Short-term use leads to reversible changes, but the long-term effects on renal function are uncertain. Assess serum creatinine before and during Qsymia treatment. 

Kidney Stones

Qsymia’s ingredient topiramate is linked to kidney stone formation. This effect is more pronounced in ketogenic diets, reducing urinary citrate and increasing pH. In children, topiramate raises urinary calcium and lowers citrate, heightening kidney stone risk. To mitigate this risk while on Qsymia, increase fluid intake to enhance urine output and reduce stone-forming substances.

Interactions With Other Medications

Similar to other medications, Qsymia has interactions [4*] to be mindful of while taking it. This list highlights some of them, and note that it’s not exhaustive. Seek advice from your healthcare provider for information on any other interactions that may be relevant to you.

Contact our medical providers to discuss your symptoms, health history, and any medications you may be taking. We will help you find a suitable weight loss solution.

Bottom Line

Qsymia, a weight-loss medication, is a combo of two FDA-approved medications. It helps people lose weight more effectively with fewer side effects compared to using each medication separately. Qsymia could be a helpful option for overweight people with health issues, but it’s essential to follow the FDA-mandated safety program and your clinician’s instructions due to potential risks. 


In clinical trials, adults taking the recommended dose of Qsymia lost an average of 15 lbs in 3 months, compared to 5 lbs in the reduced-calorie diet and exercise group (placebo). After a year, Qsymia users lost 24 lbs, while the placebo group lost 6 lbs. Individual responses vary, so discuss your expectations and potential results with your provider.

Qsymia (phentermine/topiramate ER) is a combination medication comprising two components. Phentermine, a sympathomimetic, acts in the brain to reduce appetite. Topiramate is an antiepileptic, or antiseizure, medication.

After 12 weeks (3 months) of using the prescribed Qsymia dosage, your healthcare provider will assess its effectiveness. If you have achieved a weight loss of at least 3% from your initial body weight and tolerate the medication well, you will probably continue with the exact dosage.

Yes. Qsymia can be prescribed online. MEDvidi can assist you in obtaining and managing this or other weight loss medication if you meet the prerequisites to taking it.


6 sources
  1. Long-term weight loss maintenance
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  2. Phentermine
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  3. Topiramate
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  4. Qsymia - Uses, Side Effects, and More
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  5. What to Know About CNS Depressants
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  6. Monoamine Oxidase Inhibitors (MAOI)
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Written by:

Rabia Khaliq

MSc in Applied Psychology


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This article is based on scientific evidence, written by experts and fact checked by experts.

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