Short answer: Lomaira is phentermine alone: an 8 mg tablet approved for short-term use (a few weeks), up to three times a day before meals.1 Qsymia combines phentermine with extended-release topiramate in a once-daily morning capsule approved for long-term weight management, including ages 12 and up with obesity.2 Both contain phentermine, a controlled substance. No trial has compared them.
| Lomaira | Qsymia | |
|---|---|---|
| Ingredients | Phentermine hydrochloride 8 mg (6.4 mg phentermine base)1 | Phentermine (3.75 to 15 mg, as base) + extended-release topiramate (23 to 92 mg)2 |
| Approved length | Short term: a few weeks1 | Long term2 |
| Who | Adults with BMI 30 or more, or 27 or more with other risk factors; not recommended at 16 or younger1 | Adults with obesity, or overweight with a weight-related condition; ages 12 and up with obesity2 |
| Label dosing | One tablet three times a day, half an hour before meals; can be split in half; avoid late evening doses1 | 3.75/23 mg each morning for 14 days, then 7.5/46 mg; may step up to 11.25/69 and 15/92 mg2 |
| When to stop | If tolerance develops, stop rather than raise the dose1 | If under 5% weight loss after 12 weeks on 15/92 mg; taper the top dose over at least a week2 |
| Half-life | Not stated in the label | Phentermine about 20 hours; topiramate about 65 hours2 |
| Trial results in the label | Short trials; extra weight loss over placebo described as only a fraction of a pound a week1 | Study 1, 56 weeks: −10.9% on 15/92 mg vs −1.6% on placebo; 67% vs 17% lost at least 5%2 |
| Controlled substance | Schedule IV1 | Schedule IV (the phentermine part)2 |
| Pregnancy | Contraindicated1 | Contraindicated; negative pregnancy test before starting and every month2 |
Lomaira is 8 mg of phentermine hydrochloride, equal to 6.4 mg of phentermine base, taken up to three times a day.1 Qsymia states its phentermine as base: 3.75, 7.5, 11.25 or 15 mg once a day, alongside topiramate.2 The salt vs base wording is why the numbers on the two labels do not line up directly.
The Lomaira label describes older, short trials of appetite-suppressing drugs: people lost more weight than with placebo, but only by a fraction of a pound a week, and the label calls the overall impact limited.1 The Qsymia label reports two 1-year placebo-controlled trials: in Study 1, −10.9% on 15/92 mg and −5.1% on 3.75/23 mg vs −1.6% on placebo; in Study 2, 62% on 7.5/46 mg and 70% on 15/92 mg lost at least 5% vs 21% on placebo.2 These numbers come from separate placebo-controlled trials with different people, lengths and methods, so they are not a head-to-head comparison.
The Lomaira label says it is for use on its own, not with other weight-loss drugs, and the Qsymia label says safety with other weight-loss products has not been established.12
More detail: Lomaira side effects, Qsymia side effects, the Lomaira and Qsymia dosing schedules, a missed Qsymia dose and how to store Qsymia.