The American College of Physicians (ACP) now recommends semaglutide and tirzepatide as first-line pharmacological treatments for adults with obesity or those with overweight who have weight-related comorbidities. This living clinical guidance, published in the Annals of Internal Medicine, emphasizes that these medications should be used alongside lifestyle interventions when diet and physical activity alone do not achieve therapeutic weight loss goals.
Recommended Pharmacological Pathways
The ACP guidance, developed using the Grading of Recommendations Assessment, Development and Evaluation (GRADE) approach, categorizes treatment based on a patient’s body mass index (BMI) and health status.
For adults with obesity, defined as a BMI of 30 kg/m² or higher, the ACP identifies semaglutide (Ozempic/Wegovy) and tirzepatide (Mounjaro/Zepbound) as the preferred first-line options. If these are unavailable or inappropriate, the guidance lists subsequent options in a tiered approach:
- Second-line: Phentermine/topiramate (Qsymia)
- Third-line: Liraglutide (Saxenda)
- Fourth-line: Naltrexone/bupropion (Contrave)
For patients with overweight, defined as a BMI between 27 and 30 kg/m² who also have comorbidities such as type 2 diabetes, hypertension, cardiovascular disease, obstructive sleep apnea, or dyslipidemia, the ACP recommends semaglutide and tirzepatide as first-line therapies. Liraglutide is recommended as a second-line option for this specific demographic.
Clinical Considerations for Initiation
The ACP stresses that prescribing these medications requires a comprehensive discussion between the clinician and the patient. According to the guidance, physicians should evaluate the balance of benefits and harms, medication costs, patient preferences, and clinical contraindications.
Specific safety warnings highlighted by the ACP include:
- Phentermine/topiramate: Not suitable for patients with cardiovascular disease and requires monthly pregnancy testing.
- Naltrexone/bupropion: Associated with risks regarding suicidal ideation.
- General side effects: Clinicians must monitor for muscle mass and bone density loss, as well as nutritional deficiencies, particularly in older adults.
The Challenge of Long-Term Management
A critical aspect of the new guidance is the uncertainty surrounding the duration of therapy. Editorial commentary from Dr. Christina C. Wee and colleagues at the Annals of Internal Medicine cautions against "time-limited" use of these drugs. Evidence indicates that weight regain is common once patients discontinue GLP-1 receptor agonists, suggesting that for many, these medications may need to be used long-term.
The ACP authors note that the optimal duration of treatment remains unclear and calls for further research on the long-term safety profiles of these drugs. They argue that healthcare policies must ensure consistent coverage to prevent "medication churn," which could expose patients to the risks of treatment without the benefit of sustained weight maintenance.
Key Treatment Factors at a Glance
| Feature | ACP Guidance Recommendation |
|---|---|
| Primary First-Line Agents | Semaglutide, Tirzepatide |
| Obesity Definition | BMI ≥ 30 kg/m² |
| Overweight Definition | BMI 27–30 kg/m² (with comorbidity) |
| Core Monitoring | Muscle/bone density loss, nutritional status |
| Treatment Duration | Long-term use may be necessary; avoid discontinuation-related weight regain |
The ACP intends to update these recommendations as new clinical data emerges, maintaining the guidance as a "living" document to reflect the rapid pace of research in obesity medicine. Clinicians are advised to use the lowest effective dose to balance therapeutic efficacy with the mitigation of adverse side effects.