Real-World Weight Loss Effect of Phentermine Examined

Phentermine was tied to significant weight loss and a fall in systolic BP with no significant adverse effects
Phentermine was tied to significant weight loss and a fall in systolic BP with no significant adverse effects

This article is written live from the American Association of Clinical Endocrinologists (AACE) 2017 Annual Meeting in Austin, TX. MPR will be reporting news on the latest findings from leading experts in endocrinology. Check back for more news from AACE 2017.


The use of phentermine was tied to significant weight loss and a fall in systolic blood pressure with no significant adverse effects, presented Rahil Ahmed, MD, from the University of Buffalo (SUNY), at the AACE 2017 Annual Meeting. 

A retrospective study was performed to analyze the effect of phentermine, an anti-obesity agent, in real-world clinical practice. The effect of phentermine was compared for patients with and without diabetes and for the incidence of adverse effects such as palpitation in active practice. 

A total of 97 obese patients (body weight 110±25kg) were prescribed phentermine 30–37.5mg daily for about 6 months in the clinic, of which 16 patients had no response (<1kg change). Among the responders, the overall reduction in body weight was 7.2±3.7kg or 6.4±3.1% (P<0.05) with a fall in systolic blood pressure of 3.4±1.6mmHg (P<0.05) and diastolic blood pressure of 1.6±1.3mmHg. 

When classified by presence or absence of diabetes, the data showed average weight loss in non-diabetics was 10.4±5.4kg (P<0.001) whereas systolic blood pressure fell by 6.2±3.3mmHg (P=0.09) and diastolic blood pressure fell by 1.4±1.8mmHg (not significant), respectively. Patients with diabetes had an average weight loss of 4.1±2.4kg (P=0.06) in patients with HbA1c >6.5%, 3.2±1.6kg (P=0.09) in patients with HbA1c 6-6.5%; and 7.4±4kg (P<0.01) in patients with HbA1c <6%.  "Blood pressure did not change significantly in any of the diabetes subgroups," noted Dr. Ahmed.

Study authors reported a small and non-significant increase in the heart rate in obese patients without diabetes by <2±1bpm and in patients with diabetes by 5±4bpm. The HbA1c levels did not alter significantly with the use of phentermine.

In general, the extent of the drop in systolic blood pressure was significantly less in patients with diabetes. "These results are important considering the fear of side effects currently in the minds of physicians, on the on hand, and the expense of the novel anti-obesity drugs on the other," concluded Dr. Ahmed.

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