thoughtscape NP Psychiatry · Patient education
Phentermine-Topiramate
Qsymia
Weight care should support your health and daily life. This medicine is one part of a longer-term plan.
Draft for review · Clinical content has not been revalidated for this website.
P = phentermine; T = topiramate. The diagram shows drug actions, not a proven weight benefit from each target.
What it is used for
For adults and children 12 or older with obesity, and adults with overweight plus a weight-related health condition.
It is used with nutrition and activity support. It is not approved as a combination treatment for seizures or migraines.
How it works
Phentermine and topiramate affect brain signals involved in appetite. Response varies; the exact combined effect is not fully understood.
The dose rises gradually. Your clinician checks both benefit and side effects before deciding whether to continue or increase it.
What to expect over time
FIRST 2 WEEKS
Usual start: 3.75/23 mg each morning for 14 days, then 7.5/46 mg each morning.
FIRST RESPONSE CHECK
After 12 weeks at 7.5/46 mg, your clinician checks weight change; children are assessed by BMI. A higher dose may be needed.
HIGHER-DOSE CHECK
After 12 weeks at 15/92 mg, insufficient benefit means stopping with a taper. Never increase or stop the highest dose on your own.
Taking your medication
Take your prescribed dose in the morning, with or without food. Evening doses can make sleep harder.
If you miss a dose, skip it and take the next dose the next morning. Never take an extra dose to catch up.
The highest dose must usually be reduced before stopping: sudden withdrawal can cause seizures, even without a seizure history.
When to get help
Call 911: seizure, collapse, breathing trouble, face/tongue swelling, or immediate danger from suicidal thoughts. Call 988 for crisis support.
Stop and seek urgent care: positive pregnancy test, new eye pain/blurred vision, or rash with fever, blisters, mouth sores, or swollen glands.
Prompt help: suicidal thoughts, major mood changes, overheating/low sweating, confusion, rapid breathing, severe weakness, or irregular heartbeat.
Early side effects
Tingling, dry mouth, constipation, altered taste, dizziness, and trouble sleeping are common. Tell your clinician if they persist or interfere with eating, drinking, or daily life.
Other effects to discuss
Report word-finding trouble, poor attention, or memory, anxiety, or depression. Do not drive until you know how the medicine affects you. New or worsening mood symptoms need a call.
What to keep track of
Keep weight/BMI, blood pressure/pulse, kidney, potassium, and acid-balance checks. Children need growth checks too. Diabetes medicines may need adjustment as weight changes.
Before you start
Tell your clinician about glaucoma, thyroid disease, heart problems, depression, or suicide attempts, seizures, kidney/liver disease, stones, low potassium, and medicine/substance misuse. Mention a ketogenic diet, ongoing diarrhea, or planned surgery. Do not use in pregnancy. Breastfeeding is not recommended during treatment; agree on a feeding and medication plan first.
Medicines & interactions
Pregnancy prevention
If you can become pregnant, test before treatment and every month, and use effective contraception. Stop and call immediately if pregnant. Do not wait for the next visit.
Alcohol and other medicines
Avoid alcohol. Ask before taking sedatives, sleep medicines, MAOIs, seizure medicines, diuretics, or other weight-loss products. Show the pharmacist your complete list.
Birth-control spotting
Spotting can happen with combined birth-control pills and does not by itself mean they stopped working. Keep taking contraception and tell your clinician; do not stop it on your own.
Everyday tips
Use the same morning routine and keep the dose and response-check dates written down.
Drink fluids as advised; ask about limits if you have heart or kidney disease.
Avoid overheating, especially if sweating less. Children need particular attention in hot weather.
Choose realistic nutrition/activity goals. An ineffective medicine is a reason to change treatment, not blame yourself.
Your questions, answered
Why so many pregnancy checks?
Topiramate can harm a developing baby early, before pregnancy is obvious. Testing and effective contraception are essential, not optional extras.
Can I stop suddenly?
Not routinely. The highest dose usually needs at least a one-week taper. Pregnancy or a serious reaction needs immediate stopping advice, not a delay for that routine plan.
What if I have side or back pain?
Severe side/back pain or blood in urine may be a kidney stone. Get medical advice promptly; drinking more water is not enough to assess it.
Where do I get refills?
Through a pharmacy certified for the Qsymia safety program. Plan refills early so you do not unexpectedly run out.
Storage & safety
Keep tightly closed at room temperature, dry, and secured away from children, pets, and other people. Never share. For an extra dose, call Poison Control at 1-800-222-1222; call 911 for severe symptoms.
About this information
For general information only; not a substitute for individualized medical advice. This sheet does not cover every risk or interaction. Ask your prescriber or pharmacist before changing how you take this medication.
Sources
Educational inclusion does not mean this medication or its indications are treated at this practice. Review the guide for your exact product with your prescriber or pharmacist.