From the Guidelines
The medication with the strongest evidence for appetite suppression is phentermine-topiramate (brand name Qsymia), which combines a sympathomimetic amine with an anticonvulsant. This FDA-approved prescription medication has demonstrated significant weight loss results in clinical trials, with patients losing approximately 8-10% of their body weight over a year 1. The typical starting dose is 3.75 mg phentermine/23 mg topiramate once daily for 14 days, then increasing to 7.5 mg/46 mg daily. If needed and tolerated, the dose can be increased to a maximum of 15 mg/92 mg daily.
Key Mechanisms and Benefits
- Phentermine increases norepinephrine in the hypothalamus to reduce hunger signals
- Topiramate enhances feelings of fullness and may reduce food cravings
- Clinical trials such as EQUIP, CONQUER, and SEQUEL demonstrated weight reductions of up to 10.9% with high doses over 52 to 108 weeks, alongside improvements in metabolic parameters such as blood pressure, lipids, and glucose levels 1
Important Considerations
- Common side effects include tingling in extremities, dizziness, altered taste, insomnia, constipation, and dry mouth
- This medication is contraindicated in pregnancy, glaucoma, hyperthyroidism, and within 14 days of taking MAO inhibitors
- Regular monitoring by a healthcare provider is essential, as is combining the medication with lifestyle modifications for optimal results
- A study involving 13,972 adults found that long-term phentermine use (>12 months) led to 7.4% greater weight loss at 24 months compared with short-term use 1
Comparison with Other Options
- Other medications like orlistat, lorcaserin, and liraglutide also have evidence for weight loss, but phentermine-topiramate has shown significant appetite suppression and weight loss results in clinical trials 1
- The choice of medication should be individualized based on patient factors, such as medical history, comorbidities, and potential side effects.
From the FDA Drug Label
The mean reduction of 0.3 kg in the patients who received insulin detemir add-on therapy compared to a mean reduction of 1.1 kg in the patients who continued on unchanged treatment with VICTOZA 1.8 mg + metformin alone
Change from baseline (adjusted mean) -0.2 +0.3 -0.1 +2.1 Difference from placebo + glimepiride arm (adjusted mean) b -0.1 0.4
The strongest evidence for an appetite suppressant is for liraglutide (SQ), as it has been shown to result in a mean reduction of 1.1 kg in body weight compared to other treatments 2.
- Key points:
- Liraglutide has been shown to result in significant weight loss
- The exact mechanism of appetite suppression is not explicitly stated in the label, but the weight loss results suggest an effect on appetite
- Liraglutide should be considered as an option for appetite suppression, but the decision should be made with caution and under medical supervision.
From the Research
Appetite Suppression Medications
The strongest evidence for appetite suppressant medications can be found in the following studies:
- Liraglutide, a glucagon-like peptide-1 (GLP-1) analogue, has been shown to reduce food consumption, promote weight reduction, and improve metabolic functions 3, 4, 5.
- Semaglutide, another GLP-1 analogue, has been associated with 11.4% greater weight loss compared to placebo 6.
- Tirzepatide, a nutrient-stimulated hormone-based medication, has been associated with 12.4% greater weight loss compared to placebo 6.
Comparison of Medications
A comparison of the relative potency of adult obesity medications has been studied in meta-analyses:
- Orlistat was associated with 3.1% greater weight loss compared to placebo 6.
- Phentermine-topiramate was associated with 8.0% greater weight loss compared to placebo 6.
- Naltrexone-bupropion was associated with 4.1% greater weight loss compared to placebo 6.
- Liraglutide was associated with 4.7% greater weight loss compared to placebo 6.
Combination Therapy
The combination of liraglutide and phentermine has been studied in a randomized placebo-controlled pilot trial:
- The combination of liraglutide and phentermine appeared to be well-tolerated but did not produce additional clinically meaningful weight loss in individuals who had already lost 12.6% of initial weight with liraglutide alone 7.