Qsymia vs. Adipex
See how Qsymia and Adipex compare on approved uses, dosing, side effects, and cost.
Key Takeaways
Qsymia combines phentermine and topiramate for long-term chronic weight management, while Adipex is phentermine alone approved only for short-term use of a few weeks.
Both are Schedule IV controlled substances with overlapping stimulant side effects like insomnia and dry mouth, but Qsymia requires REMS enrollment due to a birth-defect risk.
Qsymia typically costs more per month than Adipex, which reflects its combination formulation and its approval for ongoing, rather than short-term, use.
Qsymia vs. Adipex Drug Summary
Qsymia
Qsymia combines phentermine, a stimulant appetite suppressant, with topiramate, an anticonvulsant, in one once-daily capsule. It is FDA-approved for chronic weight management in adults with obesity or overweight plus a weight-related condition, and in adolescents 12 and older. The dose is increased gradually over several months to balance weight loss against side effects.
Adipex
Adipex is phentermine alone, a stimulant that suppresses appetite, taken as a once-daily or twice-daily tablet or capsule. It is FDA-approved only for short-term use, typically just a few weeks, alongside diet and exercise for weight loss in adults with obesity. Unlike Qsymia, it is not approved for long-term chronic weight management.
Qsymia vs. Adipex Side Effects
Qsymia
Adipex
Qsymia vs. Adipex Dosage
Qsymia
Adipex
| STAGE | DOSE | WHEN |
| Starting dose | 3.75 mg/23 mg once daily | Days 1-14 |
| Maximum dose | 15 mg/92 mg once daily | Week 17 onward |
| Dose changes | 3 increases | As tolerated |
| STAGE | DOSE | WHEN |
| Starting dose | 18.75 mg once daily | At the start |
| Maximum dose | 15 mg once daily | If needed |
| Dose changes | 3 increases | As tolerated |
Qsymia
| STAGE | DOSE | WHEN |
| Starting dose | 3.75 mg/23 mg once daily | Days 1-14 |
| Maximum dose | 15 mg/92 mg once daily | Week 17 onward |
| Dose changes | 3 increases | As tolerated |
Adipex
| STAGE | DOSE | WHEN |
| Starting dose | 18.75 mg once daily | At the start |
| Maximum dose | 15 mg once daily | If needed |
| Dose changes | 3 increases | As tolerated |
Qsymia vs. Adipex Indications
Qsymia
Qsymia is FDA-approved as a long-term treatment for chronic weight management, not just a short-term jumpstart. It can be used in adults with obesity, adults who are overweight with a related condition like high blood pressure, and in adolescents 12 and older with obesity.
Chronic weight management in adults with obesity
Adults who are overweight with a weight-related condition
Adolescents 12 years and older with obesity
Requires REMS certified-pharmacy dispensing
Adipex
Adipex is FDA-approved only as a short-term adjunct to diet and exercise, meant to be used for just a few weeks. It is approved for adults with obesity but not for adolescents 16 or younger, and it is not intended for ongoing, long-term treatment.
Short-term weight-loss adjunct to diet and exercise
Approved only for adults with obesity
Not approved for long-term chronic use
Not approved for patients 16 years or younger
Qsymia vs. Adipex Pros and Cons
Qsymia
Qsymia pairs phentermine with topiramate, producing greater weight loss than phentermine alone in trials, and it is approved for long-term use. Because topiramate carries a birth-defect risk, it requires REMS enrollment, monthly pregnancy testing, and certified-pharmacy dispensing.
Pros
FDA-approved for long-term chronic weight management
Approved for adolescents 12 and older
Combination mechanism may produce greater weight loss than phentermine alone
Once-daily dosing with a structured titration schedule
Cons
Requires REMS enrollment and certified-pharmacy dispensing
Monthly pregnancy testing required due to birth-defect risk
Contraindicated in glaucoma and hyperthyroidism
Roughly $200 to $350 per month without insurance, before savings programs
Adipex
Adipex has decades of use as a stand-alone appetite suppressant and typically costs far less than Qsymia. It is approved only for short-term treatment of a few weeks, so it is not designed for the type of ongoing management that chronic obesity often requires.
Pros
Roughly $50 to $150 per month without insurance, before savings programs
Simple once- or twice-daily dosing without REMS requirements
Long clinical track record dating back to 1959
Available generically in several dose strengths
Cons
Approved only for short-term use of a few weeks
Contraindicated with a history of cardiovascular disease
Rare risk of pulmonary hypertension and heart valve problems
Not approved for chronic, long-term weight management
Common Symptoms and Related Diseases You Can Explore
Explore a range of common symptoms the Doctronic Symptom Checker can help you understand.