Qsymia for Weight Loss

Qsymia diet pill

Qsymia (phentermine and topiramate) is one of several weight loss medications approved by the Federal Drug Administration (FDA). It may help with weight loss, but like all medicines, there is a risk of side effects.

Before you talk to your doctor about a Qsymia prescription, learn about the research that has been done on this weight-loss drug. Together with your doctor, you can make an informed decision about whether this medication is the right choice for you.

What is Qsymia?

Qsymia is a combination of two drugs: phentermine and topiramate. Phentermine was originally used as part of the popular phen-fen drug combination, fenfluramine. Due to safety concerns, fenfluramine was eventually taken off the market. The formulation of Qsymia is different from the phentermine-based prescriptions that were used in the past.

Topiramate is a drug that has been traditionally used for the treatment of epilepsy and migraines. Qsymia combines phentermine and topiramate to suppress appetite and reduce food intake. This combination has been proven to promote weight loss.

Qsymia may be prescribed for adults who have a body mass index (BMI) over 30. If you have a BMI of 27 or higher, along with a weight-related condition (such as type 2 diabetes or high blood pressure), your doctor may also recommend Qsymia.

People who are prescribed Qsymia are still expected to follow a healthy eating and exercise program in order to gain the full benefits of taking it.

How Qsymia Works

The exact mechanisms of action are not entirely understood, but some research suggests that this medicine may affect levels of neurotransmitters in the brain. Qsymia works to control hunger and craving, which may help people to lose weight.

Researchers believe Qsymia affects norepinephrine (a hormone and neurotransmitter) and gamma-aminobutyric acid and glutamate (both neurotransmitters, which work as chemical messengers in the body) to induce appetite suppression.


In clinical trials, patients who took a lower dose of Qsymia lost an average of 6.7% of their body weight. On the higher recommended dose (7.5mg phentermine/46mg topiramate), patients lost an average of 8.9% of their total body weight.

Studies performed on overweight and obese adults have shown that Qsymia can produce lasting health benefits and greater weight loss compared with a placebo.

Average Weight Loss

If you are thinking about taking Qsymia, you can use averages to estimate your potential weight loss range. For example, based on clinical results, a patient who weighs 250 pounds could reasonably expect to lose 17 to 22 pounds of their starting body weight. Individual results will vary, but congruent lifestyle modifications are essential, especially to achieve long-term success with weight loss.

Patients who take Qsymia should be monitored regularly by their physician. If you don't lose at least 3% of your body weight within the first 12 weeks, your doctor may advise you to stop taking the drug or take a higher dose. If you do not lose at least 5% of your weight after moving to a higher dose, it's recommended to gradually discontinue use of the drug.


Studies looking at the potential cardiovascular risks of taking Qsymia show no increased risks for current users. Still, more studies are needed to conclude whether new users could be at a greater risk.

Patients are advised to receive regular heart-rate monitoring while on Qsymia. Qsymia is not recommended in people with cardiac issues or cerebrovascular disease. If you take medications for diabetes, high blood pressure, or anxiety, your doctor may need to adjust your dosage.

With any weight loss medication, it is crucial to tailor usage to individual health conditions and current status and weigh the pros and cons. Other Qsymia concerns include:

  • Cognitive effects: Qsymia may cause addiction and adverse cognitive effects such as attention, language, and memory impairment. The long-term effects of this drug are relatively unknown.
  • Birth defects: Studies have shown an increased risk of cleft palate development in babies born to people taking topiramate (one of the ingredients in Qsymia) during their first trimester. People of childbearing age should take a monthly pregnancy test while on Qsymia so that they can stop taking the drug if they become pregnant.
  • Withdrawal: It can be dangerous to stop taking Qsymia abruptly, especially if you are on a higher dose. Some people do not respond to the effects of Qsymia at any dose and should not continue taking it.

Qsymia Side Effects

If you're considering taking Qsymia, it's important be aware of its potential side effects. 

Common Side Effects

  • Numbness or tingling in the hands, arms, feet, or face
  • Dizziness
  • Changes in the way foods taste or loss of taste
  • Trouble sleeping
  • Constipation
  • Dry mouth

Possible Side Effects

These side effects are less common but can be more serious. Contact your doctor if you experience any of these, or if you have a common side effect that is bothersome or does not go away.

  • Mood changes, including depression and suicidal thoughts
  • Increased heart rate
  • Concentration, memory, and speech difficulties
  • Kidney stones
  • Eye problems such as decreased vision, eye pain, fluid blockage
  • Fever
  • Decreased sweating despite increased body temperature
  • Seizures (if the medication is stopped too suddenly)

It's a good idea to read through the complete drug information guide (provided by your doctor or pharmacist) before you begin taking Qsymia.

How Much Does Qsymia Cost?

The total price of Qsymia depends on the pharmacy and a few other factors. Several pharmacies sell a month’s supply of Qsymia at prices ranging from $180 to $220, but your actual cost may depend on the dose that your physician prescribes. Taking the lower dose of medication is generally less expensive, averaging $120 per month wholesale.

Your insurance company may pay partially or in full for the medication. Since plans vary and change, check with your carrier to see if this drug is covered on your current plan. The makers of Qsymia also offer coupons to help you manage the cost of the medication if insurance doesn't cover it. 

If you're a person who can get pregnant, be sure to factor in the cost of a monthly pregnancy test when tallying the total cost. You can also talk to your doctor about a plan for having testing done as part of your office visits.

If you choose to invest in Qsymia, be aware that only certain pharmacies may dispense the drug. As part of an agreement with the FDA, drugmaker Vivus agreed to sell the medication only through pharmacies that take part in an educational program that ensures patients receive risk reduction information along with their medication.

Who Should Take Qsymia?

If you meet the BMI criteria and have tried other weight loss methods without success, Qsymia may be able to help. If you're considering trying to conceive in the future, use caution before starting Qsymia.

If you are on medications for other health conditions, be mindful of possible interactions and discuss them with your healthcare team. Adjust your dosages per your doctor's recommendations, and stay up-to-date on follow-up visits to monitor your body's response to Qsymia.

Frequently Asked Questions

 What should I eat while taking Qsymia?

Qsymia works best when combined with a reduced-calorie diet. Consume a diet consisting of plenty of fruits and vegetables, whole grains, lean protein, and healthy fats. Limit saturated fats and added sweeteners.

How long can you take Qsymia?

You should take Qsymia for as long as your healthcare provider has prescribed. If you experience side effects, be sure to speak to your doctor to see if stopping the medication is best. Do not stop taking the medication on your own without consulting your doctor, as this can cause adverse side effects.

How long does it take for Qsymia to work?

Qsymia starts to work immediately after you take it to reduce hunger and cravings. But it will take several days or weeks for you to lose weight resulting from a reduced appetite. Talk with your doctor about what to expect.

A Word From Verywell

Talk to your doctor about the potential health benefits of losing weight with Qsymia. Discussing your specific medical history and future plans will help you make the best decision with your provider.

It's important to remember that no pill can take the place of a balanced diet and regular physical activity. Not every medication works the same way for everyone. Monitoring your progress with your doctor will help you stay safe and avoid negative side effects.

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6 Sources
Verywell Fit uses only high-quality sources, including peer-reviewed studies, to support the facts within our articles. Read our editorial process to learn more about how we fact-check and keep our content accurate, reliable, and trustworthy.
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  3. Ritchey ME, Harding A, Hunter S, et al. Cardiovascular safety during and after use of phentermine and topiramate. J Clin Endocrinol Metab. 2018;104(2):513-522. doi:10.1210/jc.2018-01010

  4. Tak YJ, Lee SY. Long-term efficacy and safety of anti-obesity treatment: Where do we stand?. Curr Obes Rep. 2021;10(1):14-30. doi:10.1007/s13679-020-00422-w

  5. Margulis AV, Mitchell AA, Gilboa SM, et al. Use of topiramate in pregnancy and risk of oral clefts. Am J Obstet Gynecol. 2012;207(5). doi:10.1016/j.ajog.2012.07.008

  6. Qsymia. Important Safety Information.

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