Is it safe during pregnancy?

No — topiramate causes birth defects, especially cleft palate. Women who could become pregnant must use two forms of birth control while taking this drug. A monthly pregnancy test is required as part of an FDA safety programme. Talk to your doctor.

What is "brain fog" and will it affect me?

Topiramate can cause word-finding difficulties and short-term memory problems in some people — informally called "Dopamax" fog in online communities. It is more common at higher doses and often improves or resolves at lower doses. Talk to your doctor if it affects your work or daily life.

Avoid alcohol while taking this drug. Topiramate increases the sedative effects of alcohol and can worsen cognitive side effects. The combination is not recommended.

How is this different from phentermine alone?

Phentermine alone is approved for short-term use only (12 weeks). Adding topiramate allows much longer-term use and produces more weight loss than either drug on its own. Generic phentermine is also available separately at a much lower cost, but for short-term use only.

What if I can't afford the brand version?

Generic phentermine/topiramate became available in 2025 — some pharmacies offer it for $30–$80/month, compared to ~$200–$400 for brand Qsymia. Ask your pharmacist.

Qsymia (Phentermine / Topiramate ER)

Key facts

At a glance

The numbers you need before deciding.

Weight loss

9.8%

~22 lbs for a 220 lb person

Monthly cost

$30–$400/mo

Generic version (available 2025): $30–$80/month. Brand Qsymia: $200–$400/month.

How you take it

Daily capsule

One capsule each morning

Main side effect

Tingling in hands/feet

About 2 in 10 people

Fat vs lean

Limited data

No body scan data published yet for this drug

If you stop

Weight regain expected

Same pattern as similar drugs

Before you start

Learn about this treatment

Everything you'd want to know before deciding.

Weight loss resultsTrial data, timelines, what's realistic Side effectsRates, what helps, and when to call your doctor Cost & savingsList price, insurance, manufacturer programs How it works & dosageTwo drugs in one pill — dose levels and what that means for you

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Clinical evidence2 trials, all linked Phentermine aloneThe stimulant in this combination, on its own page See every treatment on one pageWhere this drug sits alongside older medicines, devices, procedures and surgery

On treatment

Already taking this?

Practical guides for people currently on this medication.

Dose titration scheduleStep-by-step dose increases Not losing weight yet?Troubleshooting — what to check first Nausea or GI issuesWhat helps right now — from trial data Missed a doseWhen to take it, when to skip

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How to take itWhen, how, storage What to eatProtein targets, meal timing, appetite shifts Week-by-week journeyWhat to expect from week 1 to month 12

Compare

Side-by-side comparisons

See how this drug compares with another, side by side.

Zepbound vs QsymiaFull side-by-side comparison Wegovy vs QsymiaFull side-by-side comparison Foundayo vs QsymiaFull side-by-side comparison Saxenda vs QsymiaFull side-by-side comparison

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Qsymia vs ContraveFull side-by-side comparison Qsymia vs XenicalFull side-by-side comparison

Clinical evidence

How it compares in trials

Average weight loss % — from individual phase 3 trials

Qsymia9.8%

Wegovy (semaglutide injection)14.9%

Zepbound (tirzepatide)20.9%

Is this right for you?

Who this tends to fit

Relevant if you

Prefer a daily pill and want to avoid injections
Want a lower-cost prescription option
Can handle its side effects (they're well-documented)

Not right if you

You are pregnant or could become pregnant (causes birth defects)
You have glaucoma or hyperthyroidism
You have a history of kidney stones
You want to avoid a controlled substance

Safety

Important cautions

Do not take this drug if you are pregnant or could become pregnant — topiramate causes serious birth defects (cleft palate). Two forms of contraception are required. A monthly pregnancy test is part of the FDA safety programme.
This drug can increase heart rate. Your doctor should monitor pulse at each visit.
Topiramate can cause a build-up of acid in the blood and kidney stones with long-term use.

See what the label says about pregnancy and breastfeeding.

Practical guide

How to take Qsymia

Take one capsule every morning — do not take in the afternoon or evening (may cause insomnia)

Swallow the capsule whole — do not crush, chew, or break it

Your doctor may increase your dose after 12 weeks if needed

Don't stop cold turkey — your doctor will help you step the dose down slowly

Common questions

FAQ

Questions to ask your doctor

→Am I a good candidate given my health history and any other conditions I have?
→Do I have any contraindications I should know about?
→What results should I realistically expect, and over what timeframe?
→Which side effects should make me contact you?
→How long should I try this before we decide if it's working?
→What happens if I need to stop — how do I come off it safely?

Written and maintained by one person · Built with agentic AI tools · Every number checked against the cited trial · Not medical advice

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Compare all optionsSee how this stacks up against other treatments Am I eligible?Check if this type of medication is right for you Talk to your doctorWhat to bring up at your next appointment Side effects comparedHow side effects differ across all treatments

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Medical disclaimer: This website is for informational purposes only and does not constitute medical advice. Always consult a qualified healthcare provider before starting, stopping, or changing any treatment. Prices shown are United States self-pay or list prices and vary by insurance and country.