Generic Name: phentermine and topiramate (FEN ter meen and toe PIR a mate)
Brand Names: Qsymia
Medically reviewed on February 16, 2018
What is Qsymia?
Qsymia contains a combination of phentermine and topiramate in an extended-release capsule. Phentermine is an appetite suppressant similar to an amphetamine. Topiramate is a seizure medication, also called an anticonvulsant.
Qsymia is used together with diet and exercise to treat obesity. This medicine is sometimes used to treat obesity that may be related to diabetes, high cholesterol, or high blood pressure.
Qsymia will not treat any these underlying conditions. Keep using any other medicines your doctor has prescribed to treat these conditions.
Do not use Qsymia if you are pregnant. This medicine may cause birth defects.
You should not take Qsymia if you are allergic to phentermine (Adipex-P, Oby-Cap, Suprenza, T-Diet, Zantryl) or topiramate (Topamax), or if you have glaucoma or overactive thyroid. Do not use Qsymia if you have used an MAO inhibitor such as furazolidone (Furoxone), isocarboxazid (Marplan), phenelzine (Nardil), rasagiline (Azilect), selegiline (Eldepryl, Emsam, Zelapar), or tranylcypromine (Parnate) in the last 14 days. A dangerous drug interaction could occur, leading to serious side effects.
Before you take Qsymia, tell your doctor if you have high blood pressure, heart disease, diabetes, liver or kidney disease, low blood levels of potassium, or if you have had a heart attack or stroke in the past 6 months.
Phentermine may be habit-forming and should be used only by the person for whom it was prescribed. Keep the medication in a secure place where others cannot get to it. Do not stop taking Qsymia suddenly, or you could have a seizure (convulsions). You may need to use less and less before you stop the medication completely. Ask your doctor how to avoid seizures when you stop using Qsymia.
Before taking this medicine
Do not use Qsymia if you have used an MAO inhibitor in the past 14 days. A dangerous drug interaction could occur. MAO inhibitors include isocarboxazid, linezolid, methylene blue injection, phenelzine, rasagiline, selegiline, tranylcypromine, and others.
You should not use Qsymia if you are allergic to phentermine or topiramate, or if you have:
overactive thyroid; or
if you are pregnant or may become pregnant.
To make sure Qsymia is safe for you, tell your doctor if you have:
high blood pressure, heart disease, heart rhythm problems, congestive heart failure;
a history of heart attack or stroke;
a history of depression, mental illness, or suicidal thoughts;
kidney disease (or if you are on dialysis);
history of kidney stones;
seizures or epilepsy;
low bone mineral density; or
if you have ever had metabolic acidosis (too much acid in your blood).
Do not use if you are pregnant, and use effective birth control to prevent pregnancy while taking Qsymia. This medicine can harm an unborn baby or cause birth defects. Weight loss during pregnancy also can harm an unborn baby, even if you are overweight. You may need to have a negative pregnancy test before starting this treatment.
Qsymia can cause irregular vaginal bleeding while you are taking birth control pills. This should not make the pills less effective in preventing pregnancy.
It is not known whether phentermine and topiramate passes into breast milk or if it could harm a nursing baby. You should not breast-feed while using this medicine.
Qsymia is not approved for use by anyone younger than 18 years old.
How should I take Qsymia?
Take Qsymia xactly as prescribed by your doctor. Follow all directions on your prescription label. Your doctor may occasionally change your dose to make sure you get the best results. Do not use this medicine in larger or smaller amounts or for longer than recommended.
Phentermine may be habit-forming. Never share Qsymia with another person, especially someone with a history of drug abuse or addiction. Keep the medication in a place where others cannot get to it. Selling or giving away this medicine is against the law.
You may take Qsymia with or without food.
Do not crush, chew, break, or open an extended-release capsule. Swallow it whole.
Drink plenty of water each day to prevent dehydration or kidney stones while you are taking Qsymia. You can easily become dehydrated while taking this medicine, which can lead to severely low blood pressure or a serious electrolyte imbalance.
You should lose at least 3% of your starting weight during the first 12 weeks of taking this medicine and eating a low calorie diet. Tell your doctor if you do not lose at least 3% of your starting weight after taking this medicine for 12 weeks.
Talk with your doctor if you feel very hungry and think the medicine is not working properly. Taking more medicine will not make it more effective and can cause serious, life-threatening side effects.
You should not stop using Qsymia suddenly or you could have a seizure (convulsions). Follow your doctor's instructions about tapering your dose.
Store Qsymia at room temperature away from moisture and heat. Keep track of the amount of medicine used from each new bottle. Phentermine is a drug of abuse and you should be aware if anyone is using your medicine improperly or without a prescription.
Qsymia dosing information
Usual Adult Dose of Qsymia for Weight Loss:
-Initial dose: Take one capsule of the lowest dose (phentermine 3.75 mg/topiramate 23 mg extended-release) orally once a day in the morning for the first 14 days.
-Maintenance dose: After 14 days, take one capsule of the recommended dose (phentermine 7.5 mg/topiramate 46 mg extended-release) orally once a day in the morning.
-Weight loss should be evaluated after 12 weeks with phentermine 7.5 mg/topiramate 46 mg extended-release. If a patient has not lost at least 3% of baseline body weight, treatment discontinuation or dose escalation should be considered as it is unlikely the patient will achieve and sustain clinically meaningful weight loss at this dose.
Use: Adjunct to a reduced-calorie diet and increased physical activity for chronic weight management in patients with an initial body mass index (BMI) of 30 kg/m2 or greater (obese) OR 27 kg/m2 or greater (overweight) in the presence of at least one weight-related comorbidity such as hypertension, type 2 diabetes mellitus, or dyslipidemia.
See also: Dosage Information (in more detail)
What happens if I miss a dose?
Take the missed dose as soon as you remember. Skip the missed dose if it is almost time for your next scheduled dose. Do not take extra medicine to make up the missed dose.
What happens if I overdose?
Seek emergency medical attention or call the Poison Help line at 1-800-222-1222. An overdose of Qsymia can be fatal.
Overdose symptoms may include confusion, hallucinations, panic, tremors, nausea, vomiting, diarrhea, stomach cramps, irregular heartbeat, rapid breathing, seizure (convulsions), and restless feeling followed by severe tiredness.
What should I avoid while taking Qsymia?
Ketogenic or "ketosis" diets that are high in fat and low in carbohydrates can increase the risk of kidney stones. Avoid the use of such diets while you are taking this medicine.
This medicine may cause blurred vision and may impair your thinking or reactions. Be careful if you drive or do anything that requires you to be alert and able to see clearly.
Drinking alcohol with this medicine can cause side effects.
Do not take any other weight-loss products without your doctor's advice.
Qsymia side effects
Get emergency medical help if you have signs of an allergic reaction to Qsymia: hives; difficulty breathing; swelling of your face, lips, tongue, or throat.
Report any new or worsening symptoms to your doctor, such as: mood or behavior changes, anxiety, panic attacks, trouble sleeping, or if you feel impulsive, irritable, agitated, hostile, aggressive, restless, hyperactive (mentally or physically), more depressed, or have thoughts about suicide or hurting yourself.
Call your doctor at once if you have:
pounding heartbeats or fluttering in your chest (even if you are resting);
sudden vision problems, sometimes with eye pain or redness;
trouble concentrating, problems with speech or memory;
a seizure (convulsions);
feeling very thirsty or hot, decreased sweating, hot and dry skin;
low blood sugar--headache, hunger, weakness, sweating, irritability, dizziness, or feeling jittery;
signs of metabolic acidosis--confusion, vomiting, lack of energy, irregular heartbeats; or
signs of a kidney stone--pain in your side or lower back, blood in your urine, painful or difficult urination.
Common Qsymia side effects may include:
numbness or tingly feeling;
sleep problems (insomnia); or
dry mouth, changes in your sense of taste.
This is not a complete list of side effects and others may occur. Call your doctor for medical advice about side effects. You may report side effects to FDA at 1-800-FDA-1088.
See also: Side effects (in more detail)
What other drugs will affect Qsymia?
Taking this medicine with other drugs that make you sleepy can worsen this effect. Ask your doctor before taking Qsymia with a sleeping pill, narcotic pain medicine, muscle relaxer, or medicine for anxiety, depression, or seizures.
Tell your doctor about all your current medicines and any you start or stop using, especially:
valproic acid or divalproex sodium (Depakene or Depakote)
birth control pills; or
a diuretic or "water pill."
This list is not complete. Other drugs may interact with phentermine and topiramate, including prescription and over-the-counter medicines, vitamins, and herbal products. Not all possible interactions are listed in this medication guide.
Remember, keep this and all other medicines out of the reach of children, never share your medicines with others, and use Qsymia only for the indication prescribed.
Always consult your healthcare provider to ensure the information displayed on this page applies to your personal circumstances.
Copyright 1996-2018 Cerner Multum, Inc. Version: 2.01.
More about Qsymia (phentermine / topiramate)
- Qsymia Side Effects
- During Pregnancy
- Dosage Information
- Drug Images
- Drug Interactions
- Compare Alternatives
- Support Group
- Pricing & Coupons
- En Español
- 481 Reviews
- Drug class: anorexiants