Jeffrey Panko NP Psychiatry · Patient education
Phentermine–topiramate
Qsymia / Extended-release weight-management capsules
A guide for adults taking phentermine–topiramate.
Follow the directions on your prescription and your provider's recommendations.
Formulations: Extended-release capsules contain fixed amounts of both medicines. The dose is increased in stages and cannot be substituted directly with separate tablets.
What it is used for
This combination supports long-term weight management in eligible patients alongside nutrition and activity changes. This guide is for adults. It is not a treatment for bipolar disorder or depression.
How it works
Phentermine increases sympathetic signaling that can reduce appetite. Topiramate affects several nerve-signaling pathways and can also influence appetite and food intake.
What to expect over time
Weight response is assessed at defined 12-week dose milestones. Your provider will decide whether to increase, continue, or taper treatment based on response and adverse effects.
Taking your medication
- Take each morning, with or without food, following the starting schedule.
- Skip a missed dose and resume the next morning; do not double.
- Do not stop the highest dose suddenly; a prescribed gradual reduction is needed to reduce seizure risk.
- If pregnancy occurs, stop Qsymia and contact your provider immediately.
When to get help
Emergency symptoms. Get emergency care for sudden eye pain or blurred vision, a seizure, severe allergic reaction, chest pain, or collapse. Eye symptoms can signal acute glaucoma.
Prompt medical advice. Report major mood changes, rapid breathing, reduced sweating with overheating, or significant cognitive problems promptly.
If you feel unsafe or have thoughts of self-harm, call 911 or go to an emergency department.
Possible side effects
- Tingling in hands or feet
- Dry mouth, constipation, or altered taste
- Insomnia, dizziness, or faster pulse
- Word-finding, memory, or concentration problems
Keeping track of treatment
Some side effects resolve with time; others may require a change of medication. Discuss persistent or bothersome side effects with your provider.
Report changes in mood, behavior, concentration, or suicidal thoughts. Antiseizure medicines carry a warning about suicidal thoughts and behavior.
Keep follow-up appointments. Your provider may adjust treatment based on symptoms, kidney or liver function, other medicines, and any recommended laboratory tests.
Check weight, pulse, and laboratory measures such as bicarbonate, potassium, and kidney function. People who can become pregnant need a negative test before treatment and monthly testing.
If you take too much
For a suspected overdose, call Poison Control at 1-800-222-1222 immediately, even if you feel well. Call 911 for a seizure, collapse, trouble breathing, or inability to wake.
Before you start
Do not use during pregnancy, with glaucoma or hyperthyroidism, or within 14 days of an MAOI. Use effective contraception. Discuss kidney stones, mood disorders, eye problems, and heart disease. Discuss breastfeeding before treatment.
Medicines and interactions
Review all your medications with your provider, including over-the-counter medicines and supplements. Have new medications checked before taking them.
Other stimulants, weight-loss medicines, and decongestants may add cardiovascular effects. Alcohol and sedatives can worsen impairment.
Carbonic-anhydrase inhibitors and certain diets can add acidosis or kidney-stone risk. Review diuretics and other seizure medicines.
Everyday tips
Use reminders and arrange refills before you run out.
Avoid driving until you know how treatment affects you; seizure-related driving restrictions may also apply.
Your questions answered
Why are pregnancy tests required?
Topiramate can harm fetal development, including causing oral clefts. Testing and contraception are part of treatment even before pregnancy is recognized.
What if my birth-control pill causes spotting?
Contact your provider, but do not stop contraception because of spotting. Review the exact method and interaction guidance.
Storage and safety
Keep medication in its labeled container, away from excess heat and moisture and out of reach of children and pets. Do not share it. Ask a pharmacy about disposal of unused medication.
Sources
About this information
Educational handout; does not replace your prescription or provider's recommendations.
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.