Short answer: The Qsymia label starts at 3.75 mg/23 mg once each morning for 14 days, then 7.5 mg/46 mg. After 12 weeks, adults who have lost less than 3% of body weight go to 11.25 mg/69 mg for 14 days, then 15 mg/92 mg. If weight loss is under 5% after 12 weeks on 15 mg/92 mg, Qsymia is stopped, tapering over at least a week.
This is what the FDA label says. Follow your prescriber. Your prescriber may use a different dose or pace than the label's standard schedule.
What Qsymia is approved for: Qsymia is approved, with a reduced-calorie diet and more physical activity, to reduce excess body weight and keep it off long term in adults and children 12 and older with obesity, and in adults with overweight and at least one weight-related condition (section 1). The label says its effect on heart disease and death has not been established. Phentermine is a Schedule IV controlled substance (section 9.1).
Source
QSYMIA (phentermine and topiramate extended-release capsules), for oral use, CIV, prescribing information and Medication Guide. VIVUS. DailyMed, version published April 24, 2026. DailyMed setid 40dd5602-53da-45ac-bb4b-15789aba40f9
Qsymia is a capsule taken by mouth once daily in the morning, with or without food. The label says to avoid evening doses because they can cause insomnia (section 2.2).
It comes in four strengths (phentermine/topiramate): 3.75 mg/23 mg, 7.5 mg/46 mg, 11.25 mg/69 mg and 15 mg/92 mg (section 3).
Before starting and during treatment, the label recommends a negative pregnancy test (then monthly) for people who can become pregnant, and blood tests for bicarbonate, creatinine and potassium, plus glucose for people with type 2 diabetes on diabetes medicines (section 2.1).
The table below is the label's schedule, from the Dosage and Administration section. Numbers are copied exactly; the section is in brackets.
| Step | Once-daily dose (phentermine/topiramate) | How long | What the label says |
|---|---|---|---|
| Start | 3.75 mg/23 mg | 14 days | Starting dose |
| Recommended dose | 7.5 mg/46 mg | 12 weeks, then check | If an adult has lost less than 3% of body weight (or a child less than 3% of BMI), go to the next step |
| Escalation | 11.25 mg/69 mg | 14 days | Bridge step to the top dose |
| Top dose | 15 mg/92 mg | 12 weeks, then check | If an adult has lost less than 5% of body weight (or a child less than 5% of BMI), stop Qsymia |
| Stopping 15 mg/92 mg | 15 mg/92 mg every other day | At least 1 week | Taper before stopping, to avoid a possible seizure |
In children 12 and older, the rate of weight loss is monitored; if it is more than 2 lbs (0.9 kg) a week, a lower dose may be considered.
With moderate or severe kidney impairment (CrCl under 50 mL/min), the maximum is 7.5 mg/46 mg once daily. Qsymia is avoided in end-stage kidney disease on dialysis.
With moderate liver impairment (Child-Pugh 7 to 9), the maximum is 7.5 mg/46 mg once daily. Qsymia is avoided in severe liver impairment.
Stopping topiramate abruptly has been linked to seizures, so the 15 mg/92 mg dose is tapered (section 2.3).
With non-potassium-sparing diuretics, potassium is measured before and during treatment.
Birth control pills may cause spotting with Qsymia but the label says pregnancy risk is not expected to rise; the pill is not stopped if spotting occurs.
The Medication Guide says: if you miss a dose of Qsymia, wait until the next morning to take your usual dose, and do not double your dose. The prescribing information gives no separate missed-dose rule.
More on this: missed a dose of Qsymia.
Qsymia is not taken during, or within 14 days of stopping, an MAOI, because of the risk of a hypertensive crisis.
The label says the safety and effectiveness of Qsymia with other weight-loss products, including prescription, over-the-counter and herbal products, have not been established.
In Dose Track you set up Qsymia as a protocol with the dose and schedule your prescriber gave you. A protocol can hold dose steps, each with its own dose and length in days or weeks, so a step-up plan like the one on the label can be entered once and the app moves to the next step on its own. Reminders follow the schedule, and every dose is logged with the date and time, so you can see which step you are on and when your last dose was. The app follows what you enter; it does not choose or change a dose.
This page is what the FDA label says, in plain words. It is not medical advice. Follow your prescriber, and ask them or your pharmacist about anything here.