Table of Contents


Last updated Aug. 7, 2018

About Qsymia

qsymia pillsQsymia is a prescription weight loss drug that contains a combination of phentermine HCL (Adipex) and topiramate extended-release (Topamax). While phentermine HCL works as the appetite suppressant, topiramate-ER reduces cravings.

The medication is a relatively new, having recently earned FDA approval in July 2012. During clinical trials this medication was known as Qnexa, but FDA officials eventually asked the manufacturer (VIVUS, Inc.) to change the pill’s name to avoid confusion.

Qsymia is prescribed for the treatment of exogenous obesity in adults with a BMI >30. It is also indicated for overweight adults (with a BMI >27) that have an additional complication such as type 2 diabetes or high blood pressure.

Like all weight loss drugs, Qsymia should be combined with healthy diet and regular exercise to achieve the best weight loss results. The medication can give you a head start by suppressing appetite and boosting energy, but lifestyle changes (like healthy diet and exercise habits) are important too.

Qsymia has been approved for the chronic management of obesity (up to 3 years) while traditional phentermine pills like Adipex can only be taken for up to 12 weeks.

Prior to earning its FDA approval in 2012, this combination pill was evaluated in several clinical studies, five of which played a major role in ensuring the medication’s approval.

As of 2017, over two million Qsymia prescriptions have been filled.

Good to know

  • If you want to buy Qsymia online, please visit Where to Buy Qsymia

  • We also recommend the Qsymia alternative, Phen Caps. Visit to order Phen Caps Online

The two active ingredients in Qsymia diet pills are: phentermine HCL and topiramate extended-release.


Phentermine HCL is a sympathomimetic amine that acts as a central nervous system stimulant and appetite suppressant. It is used almost-exclusively for weight loss. The molecule looks like this:

Phentermine hidrochloride


Topiramate extended-release is a sulfamate-substituted monosaccharide with anticonvulsant property. It is used primarily as an anti-seizure medication, but it is also prescribed to reduce migraines and, in conjunction with phentermine, for weight loss. The molecule looks like this:

Qsymia topiramate

The inactive ingredients in Qsymia are: methylcellulose, sucrose, starch, microcrystalline cellulose, ethylcellulose, povidone, gelatin, talc, titanium dioxide, FD&C Blue #1, FD&C Red #3, FD&C Yellow #5 and #6, and pharmaceutical black and white inks.

The pill’s two active ingredients in work together to produce a uniquely effective weight loss medication.

Phentermine works as a central nervous system stimulant to activate a “fight or flight” -like response. Like amphetamines, phentermine sends signals to the brain to suppress huger and boost energy. These biological changes help humans evade danger in stressful situations, but the same reactions can also promote weight loss. With less appetite and more energy, it’s easier to eat reasonable portions and exercise regularly. So, phentermine is a highly-effective weight loss medication.

Topiramate extended-release (topiramate-ER), also known under the trademark Topamax, bolsters phentermine’s effectiveness with weight loss. It was originally prescribed as an anti-seizure and migraine medication, but doctors eventually noticed it also helped boost phentermine. Topiramate-ER aids in weight loss by increasing the feeling of being full, making foods taste less appealing and increasing caloric expenditure.

When used for weight loss, topiramate (Topamax) is primarily used with phentermine – either in Qsymia, or prescribed off-label as half of a generic substitute for the combined pill. Some small, short-term studies also suggest that this medication could prove useful in the management of binge eating disorder, or weight loss in general, but experts have thus-far concluded that the potential risks outweigh potential benefits. For this reason, prescribing topiramate for weight loss remains an off-label use that should only be pursued as a last resort, and after extensive patient counseling.

No, there is no generic alternative at this time. VIVUS is the only company that produces a combination pill of phentermine HCL plus topiramate-ER.

However, some practitioners will prescribe phentermine HCL and topiramate-ER at the same time to emulate the effective drug combination. When the two individual medications are taken simultaneously, they come as two separate pills and exist as an off-label combination. Since the generic option is two separate pills instead of one combined pill, a doctor needs to specifically prescribe the distinct medications (instead of Qsymia). Taking two separate generic medications is typically cheaper than purchasing the brand-name pill. However, some feel Qsymia is better than taking the two medications separately because it allows for a guaranteed, precise dosing of the medication, and the single pill is specifically approved by the FDA.

Yes. One of the active ingredients, phentermine HCL, is classified as a schedule IV drug both in the US and abroad. This drug class is assigned due to the medication’s potential for abuse and/or addiction, despite its proven medical purpose. As a result, Qsymia is also considered a class IV controlled substance and can only be obtained with a valid doctor’s prescription. It is illegal and potentially dangerous to take this diet pill without a prescription.

Many people wonder whether Qsymia will appear on a standard drug test or not. Unfortunately, this medication can produce a false-positive for amphetamines on a urine drug screen due to phentermine’s chemical structure. Even though phentermine is NOT an amphetamine, its chemical structure resembles that of amphetamines, so this medication can sometimes produce a false-positive.

Thankfully, prescription weight loss drugs are distinguishable from other drugs with further testing. Still, Qsymia is classified a controlled substance so most testing agencies will require current/valid proof of prescription, regardless of the ultimate findings.

This medication is manufactured by VIVUS, Inc. – a California-based pharmaceutical company. They currently produce medications related to obesity, sleep and sexual health. Below is their contact information: 

Qsymia vivus logo

1172 Castro Street
Mountain View, CA 94040

Company Phone: 650-934-5200
Medical Information Phone: 1-888-998-4887

Corporate website: 
Medication Website:

Dosage & Side Effects

This medicine is taken once daily by mouth. Most patients take their pill early in the morning – either with or without food. Avoid taking this medication late in the day given that the phentermine can disrupt regular sleep patterns.

Qsymia is currently available in 4 different doses. Individual dosing can only be determined by a healthcare professional, but patients typically start on a very low dose and then gradually progress towards the maximum dose over the course of multiple months. Daily dosage ranges from 3.75mg/23mg to 15mg/92mg – both presented as phentermine HCL/topiramate-ER.

All 4 doses of Qsymia are available as capsules, and all contain a combination of phentermine hydrochloride and topiramate extended-release. The number to the left of the slash indicates milligrams of phentermine, while the number to the right of the slash denotes milligrams of topiramate-ER contained within each capsule.


qsymia 375/23
Qsymia 3.75/23 (phentermine 3.75 mg and topiramate 23 mg extended-release)


Qsymia 37.5/46
Qsymia 7.5 mg/46 mg (phentermine 7.5 mg and topiramate 46 mg extended-release)


Qsymia 125/69
Qsymia 11.25 mg/69 mg (phentermine 11.25 mg and topiramate 69 mg extended-release)


Qsymia 15/92
Qsymia 15 mg/92 mg (phentermine 15 mg and topiramate 92 mg extended-release)


Doctors typically start patients on the lowest strength possible, and then gradually increase dosage according to a set schedule. If the medication isn’t working, use should be discontinued. NEVER exceed the maximum recommended dose of 15mg/92mg per day.

A typical treatment plan may progress as follows:

Start treatment with one 3.75mg/23mg capsule each morning for 2 weeks. Starting in week 3, take one 7.5mg/46mg capsule each morning. At 3 months, the doctor should either stop the medication (if it’s not proving effective) or increase dosage to 11.25mg/69mg once per day. After 2 weeks on 11.25mg/69mg, daily dosage will be increased to the maximum of Qsymia 15mg/92mg.

Individual dosing schedule can only be determined by a medical professional. 

  • Always take Qsymia EXACTLY as prescribed.
  • NEVER take at a different dose, or take the medication more or less often, than prescribed.

Qsymia dosage 1Qsymia dosage 2

When the treatment period comes to an end, it’s important to gradually decrease use instead of stopping suddenly. Abrupt cessation of this medication increases the risk of seizures.
For more specifics about taking and dosing this medication, please view VIVUS’ medication guide here.

If you miss a dose of Qsymia, it’s best to skip the missed dose and then continue taking the medication normally the following day. NEVER take a double dose to make up for a missed pill. Taking more medicine than directed can lead to a dangerous overdose.

If you suspect a Qsymia overdose, call 911 (emergency services) or poison control right away.

Call 911 immediately if the person is having trouble breathing, seizing or passing out.

Symptoms of an overdose could include:

  • Rapid breathing
  • Unusual restlessness
  • Fast, slow or irregular heartbeat
  • Chest pain
  • Hallucinations
  • Seizures
  • Loss of consciousness
  • Severe drowsiness

If you’re in the US, you can call poison control at 1-800-222-1222. You can also receive online advice from the Poison Control Centers here.

Qsymia is a highly effective weight loss medication, but like all medications it also carries the risk of side effects. These possible side effects range from relatively minor to very severe. For this reason, it’s important to speak with your doctor about potential reactions before starting Qsymia. As treatment progresses, stay in-touch so that he or she can work with you to manage any problems that arise while taking the medication.

Call your doctor or seek immediate medical attention if you experience any serious side effects, or if any side effect bothers you or does not go away. A physician or other medical professional is the best person to diagnose and treat any adverse reaction to Qsymia.

Serious Side Effects

If you experience symptoms that indicate any of these serious Qsymia side effects, contact your doctor right away or seek immediate medical attention.

Increased risk of birth defects

When taken during pregnancy, Qsymia increases the risk of serious birth defects called cleft lip and cleft palate. These defects can occur early in pregnancy (even before a woman realizes she’s pregnant), so it’s critical that women use reliable contraception while taking this medication. You will also need a negative pregnancy test before starting this medication, and each month during treatment.

If you realize you are pregnant, tell your doctor right away and stop taking Qsymia. This medication is considered Pregnancy Category X.

Any and all cases of pregnancy while on Qsymia should be reported to:

  • FDA MedWatch program at 1‑800‑FDA‑1088 or
  • Qsymia Pregnancy Surveillance Program at 1‑888‑998‑4887.

Increase in heart rate

Qsymia can cause an increase in heart rate, so your doctor should monitor this vital while you’re undergoing treatment. If you feel like your heart is racing or pounding at rest, call your doctor.

Suicidal thoughts and/or actions

One of the active ingredients in Qsymia, topiramate, can affect mood. Call your doctor right away or seek immediate medical attention if you have new, worse or worrying mental health symptoms.

Serious changes in mood may include: thoughts about suicide or dying, attempts to commit suicide, new or worse depression, new or worse anxiety, panic attacks, feeling agitated or restless, new or worse irritability, trouble sleeping (insomnia), an extreme increase in activity or talking (mania), acting aggressive, being angry, or exhibiting violent behavior, acting on dangerous impulses, or other unusual changes in behavior or mood.

Serious eye problems leading to vision loss

Topiramate can also cause serious eye problems that, if left untreated, may lead to vision loss. Symptoms of this side effect include sudden decreases in vision, with or without pain and redness, or a blockage of fluid that leads to pressure build-up (secondary angle closure glaucoma). Contact you doctor or seek medical attention immediately if you experience either of these reactions.

Other Serious Side Effects

Below are some of this medication’s other serious side effects.

Tell your doctor immediately if you experience any of the following:

  • Difficulties with concentration, memory or speech
  • Metabolic acidosis (evidenced by tiredness, loss of appetite, changes in heartbeat and/or confusion)
  • Low blood sugar (hypoglycemia) in people with type 2 diabetes
  • Dizziness or lightheadedness
  • Changes in blood pressure
  • Kidney stones (evidenced by severe side or back pain and/or blood in the urine)
  • Decreased sweating and fever
  • Seizures (after stopping Qsymia abruptly)

Common Side Effects

While many patients take Qsymia without experiencing any serious side effects, the incidence of minor side effects is slightly higher.

Here are some of the most common reactions:

  • Numbness or tingling in limbs and/or face (paranesthesia)
  • Changes in, or loss of, taste (dysgeusia)
  • Constipation
  • Trouble sleeping (insomnia)
  • Dry mouth (xerostomia)

Tell your prescribing doctor if you have any side effect that doesn’t go away or bothers you. This list does NOT contain all of the possible side effects of Qsymia.

For more information about side effects or reactions, contact your prescribing doctor or pharmacist.

How to Report Side Effects

Always contact your prescribing doctor for advice about side effects. Your personal physician can help address questions or concerns regarding normality of reactions, how to cope with side effects, etc.

If you would like to report side effects to the manufacturer (VIVUS, Inc.), you can call them at 1‑888‑998‑4887.

If you would like to report side effects to the regulatory authorities, you can call the FDA at 1‑800‑FDA‑1088 or file a report at

This medication is generally regarded as safe when used as directed, but it is not safe or appropriate for everyone.


Qsymia is contraindicated in the presence of:

  • Pregnancy
  • Glaucoma
  • Hyperthyroidism (overactive thyroid)
  • Prior reaction to sympathomimetic amines
  • Current or recent (≤ 2 weeks) monoamine oxidase inhibitor (MAOI) use

If you have any of these conditions, this medication is NOT right or safe for you. Continue reading for a more extensive, albeit not complete, list of other conditions that your doctor needs to assess.

Warnings and Precautions

In addition to the outright contraindications, there exist a number of warnings and precautions surrounding Qsymia use.

Be completely honest with your prescribing doctor about your current/recent medications and supplements, and entire medical history. Due to this drug’s potential for negative interactions, your doctor needs the complete information.

Make sure to tell your doctor if you have, or have ever had:

  • Any allergies, especially if you’ve ever reacted to any sympathomimetic amine
  • Heart disease or stroke
  • High blood pressure or pulmonary hypertension
  • Glaucoma
  • Personal or family history of a substance use disorder
  • Mental illness or mood disorders (such as depression or anxiety)
  • Hyperthyroidism (overactive thyroid)
  • Seizures
  • Liver or kidney disease (including kidney stones)
  • Metabolic acidosis (or any condition that puts you at higher risk such as chronic diarrhea, a ketogenic diet or low bone density)

Also tell your doctor if you:

  • Have diabetes mellitus
  • Use marijuana
  • Think you may become pregnant

While taking this medication, you should AVOID:

  • Alcohol
  • Activities that may cause you to overheat
  • Driving or operating heavy machinery, until you know how the medicine affects you

Clinical trials did not include minors, so this medication is not indicated for pediatric patients under the age of 18.


Always keep a current list of all of the prescription & OTC medications, herbal supplements, vitamins and drugs that you regularly consume. You should know the dosages as well. NEVER change your medication or supplement use without first consulting your doctor and pharmacist. Due to the high potential for drug interactions, it’s vital that your doctor and pharmacist have all of the most recent information from you.

Some of the substances that negatively interact with Qsymia include:

  • Monoamine oxidase inhibitors (MAOIs)
  • Weight loss drugs (e.g. Orlistat, ephedra, etc.)
  • Stimulants, including caffeine
  • Drugs that cause drowsiness (antihistamines, pain killers, muscle relaxants, etc.)
  • Products that raise heart rate and/or blood pressure (e.g. cough & cold medicines)

Be certain to tell your doctor if you take:

  • Birth control pills
  • Diuretics/water pills
  • Any medication that lessens your ability to think or concentrate, or impairs muscle coordination
  • Carbonic anhydrase inhibitors
  • Seizure medication

This is NOT a complete list.A medical professional is the only person who can assess if Qsymia is safe in the context of your other medications and supplements.

A Risk Evaluation and Mitigation Strategy (REMS) is a strategy for healthcare professionals to ensure that a prescribed drug’s benefits outweigh that same medication’s risks for a specific patient. The FDA has required a REMS for Qsymia given the drug’s potential for serious side effects.

The Qsymia REMS is targeted at informing physicians and women of a reproductive age about the risks associated with taking this medication. More specifically, the Qsymia REMS emphasizes the importance of not becoming pregnant while using this medication because Qsymia’s potential to cause birth defects. Therefore, you and your doctor should take measures to ensure that you don’t become pregnant, and discontinue the medication immediately if pregnancy occurs.

To read the Qsymia REMS in its entirety, please visit

Results & Reviews

Based on results of Qsymia’s FDA approval studies, the average weight loss in the first three months is 15-19 pounds, with a typical loss of 2-3 inches off your waist. If you continue taking this medication for an entire year, the average weight loss is 24-32 pounds with an average loss of 4-5 inches lost around the waist. As with any weight loss regimen, results vary based on a variety of factors including starting weight, diet, activity and dosage.

Qsymina infographic

The combination of phentermine HCL and topiramate-ER has been studied extensively for weight loss. Below you will find a review of some recent findings on Qsymia:

Effectiveness of Qsymia

The review, published by Cosentino, Conrad & Uwaifo online in 2011, looked at a group of clinical trials to assess the usefulness of combining phentermine HCL and topiramate-ER for weight loss.

They analyzed the five major clinical trials that played a critical role in the FDA’s decision to approve Qsymia for the chronic management of obesity (in combination with behavioral changes like diet & exercise). These studies lasted between 6 months and 2 years, and tested all of the currently-available doses of Qsymia except for 11.25/69. Weight loss results were measured as percent weight loss from baseline (starting weight). At the maximum dosage plus a 500 kcal/day calorie deficit, patients experienced an average of 9.2-14.4% weight loss in 6-24 months. Beyond weight loss, these studies also suggest that weight loss with the combination of phentermine HCL and topiramate-ER statistically improves waist circumference and blood sugar control. In fact, one trial (SEQUEL) showed a 72% reduction in development of new type 2 diabetes among study participants.

For the full text of this review (and access the five major studies individually), please click here.

Cardiovascular Effects of Qsymia

Curious about the effects of this combination on your heart, in particular? This review, published by Jordan et. al in 2014, examined cardiovascular data associated with the use of phentermine HCL and topiramate-ER for weight loss.

Research shows that just 5-10% weight loss significantly improves cardiovascular risk factors in the obese population. However, many people express concern about the use of pharmacological therapy to achieve this goal. Jordan and his team analyzed available trial data to assess the cardiovascular effects associated with taking phentermine HCL and topiramate-ER as an adjunct therapy to behavioral modifications (like healthy diet and increased activity). The reviewed studies indicate that this drug combination is safe and effective in patients with low-to-moderate cardiovascular risk. Still, future trials will further examine the long-term effects of Qsymia on the cardiovascular system, and on the patient as a whole.

Read the full text of this review.

Wayne started at 275 pounds and lost 61 pounds with phentermine! He was originally started on topiramate to help control cravings. However, after a couple of weeks the weight loss clinic team decided to add phentermine to promote further weight loss. He emphasizes the importance of making-over your lifestyle to include more healthy food and exercise, but also credits weight loss medications with helping him succeed.

More phentermine success stories.

Qsymina Before and after picture

Facebook groups are great places to go for advice and tips from real phentermine users, including Qsymia users! They are active, suppportive and educational online communities where you can ask questions, connect with others and share experiences.

Join one of our lively Facebook support groups today!

Now you have the factual information you need about Qsymia, but will this medication really help you reach your weight loss goals? If you visit our Qsymia reviews page, you can read dozens of reviews submitted by real users. They rate the medication, comment on its effectiveness and talk about side effects they experienced.

As an example of what you’ll find on this page, Karlee submitted the following review:

Qsymia - Worked really well but expensive

Effectiveness: 4/5 - Ease of Use: 4/5 - Satisfaction: 5/5

The Qsymia brand worked well for me but because of the price my insurance decided it wouldn't cover it after the first month. That month I lost 14 lbs taking the yellow capsules (11.25 phen/69 topiramate) then my doctor switched me to phentermine 37.5mg. That didn't agree with me and seemed to wear off quickly so I'm hoping to go back in a month and try the combo of phentermine and topamax as I have another 35 to lose.

To see more comments like this one, please visit our Qsymia reviews page.

Qsymia vs. Other Diet Pills

Qsymia and Contrave are both combination medications for weight loss, but they contain different active ingredients. Contrave uses a combination of naltrexone and bupropion extended-release to suppress appetite and control cravings. Naltrexone is individually used to manage addiction, while bupropion is an anti-depressant that’s also used to facilitate smoking cessation. Similar to Qsymia, Contrave’s suggested dosing schedule directs doctors to gradually increase patients’ dose over time. Like Qsymia, Contrave can also be taken more chronically than some other prescription weight loss medications (like phentermine).

To read more about Contrave, visit Orexigen Therapeutics, Inc.’s website.

Instead of combining two medications, Belviq contains just one active ingredient: lorcaserin hydrochloride (lorcaserin HCL). This second medication works by priming our brain register and respond to signals of fullness (circulating serotonin) more quickly. While Qsymia is always taken once a day, Belviq can either be taken once or twice a day depending on formulation. While common side effects are similar between the Qsymia and Belviq, serious side effects differ.

To learn more about Belviq, visit Eisai Inc. and Arena Pharmaceuticals GmbH’s website.

Qsymia contains phentermine as one of its active ingredients, so the medications are very similar. Phentermine alone is typically cheaper than Qsymia (or buying the two medications separately), but should only be used for 12 weeks at a time. On the other hand, Qsymia can be taken for a longer period of time. A downside of this combined pill is that it can cause additional serious side effects including vision problems, depression and – if taken while pregnant – serious birth defects. Still, some patients report that they lose more weight with Qsymia than with phentermine alone.

Good to know

  • If you want to buy Qsymia online, please visit Where to Buy Qsymia

  • We also recommend the Qsymia alternative, Phen Caps. Visit to order Phen Caps Online