Research
Hormonal
Sympathomimetic agents (phentermine, phentermine/topiramate, naltrexone/bupropion) cause mild gastrointestinal side effects (constipation, dry mouth, nausea) with lower discontinuation rates compared to GLP-1 agonists.
If you take a sympathomimetic medication like phentermine or naltrexone/bupropion, you may experience mild side effects like constipation or dry mouth. These are generally less severe than the GI side effects associated with GLP-1 agonists. Stay hydrated and monitor your symptoms.
ModerateSupportsMEDIUM confidence
Sympathomimetic agents such as phentermine and combinations like phentermine/topiramate or naltrexone/bupropion, produced fewer GI events overall. The most common effects were mild constipation, dry mouth, or dysgeusia.
Why this rating
Based on smaller studies and shorter follow-up.
Source
Gastrointestinal Adverse Effects of Anti-Obesity Medications in Non-Diabetic Adults: A Systematic Review
Ehab Takrori et al. · Medicina · 2025
DOI 10.3390/medicina61111987
systematic_reviewCited 5×
Read the paper DOI resolved against Crossref · corpus check 2026-06-10
More from this paper
- GLP-1 receptor agonists (semaglutide, liraglutide, tirzepatide) cause dose-dependent gastrointestinal adverse effects (nausea, vomiting, diarrhea, constipation) primarily during dose escalation, leading to discontinuation in 3-17% of non-diabetic users.Good
- Orlistat causes mechanism-specific gastrointestinal adverse effects (steatorrhea, fecal urgency, flatulence) due to fat malabsorption, but these are generally manageable with dietary modification.Good
Related findings · Hormonal
- Initial treatment for type 2 diabetes should be a combination of metformin and either an SGLT-2 inhibitor or a GLP-1 receptor agonist to achieve cardiorenal protection, rather than monotherapy or older agents like sulfonylureas.Strong
- For patients with specific monogenic obesity syndromes (leptin deficiency, POMC/PCSK1/LEPR mutations), targeted pharmacotherapy (recombinant leptin or setmelanotide) is highly effective and should be prioritized, unlike in polygenic obesity.Strong
- Continued weekly administration of 2.4 mg subcutaneous semaglutide prevents weight regain and promotes further weight loss in adults with overweight or obesity, whereas switching to placebo results in significant weight regain.Strong
This is one finding among thousands. Every one is graded and traced to its source, so you can see what the evidence actually supports. Browse the research →