Add-on phentermine enhances weight loss in obese teens


Short-term use of the norepinephrine reuptake inhibitor phentermine in addition to standard of care (SOC) lifestyle modification therapy may lead to greater weight loss in adolescents with obesity compared with SOC alone, according to a study.

Researchers examined the medical records of obese adolescents treated in a paediatric weight management clinic to examine the effect of using phentermine as an add-on to SOC lifestyle modification therapy. The population comprised 25 patients (mean age 16.1 years; mean BMI, 41.2 kgm−2) receiving phentermine plus SOC and 274 patients (mean age 14.9 years; mean BMI, 38.1 kgm−2) receiving only SOC.

The patients were evaluated at 1, 3 and 6 months using generalized estimated equations to determine the differences between the two treatment interventions. Age, sex and BMI were included in the analysis as potential confounders. Robust variance standard error estimates were used to calculate confidence intervals and p-values.

Results showed that the percent change in BMI overall was greater in the phentermine group than in the SOC-only group. The respective changes at 1, 3 and 6 months were −1.6 percent (95 percent CI, −2.6 to −0.6; p=0.001), −2.9 percent (−4.5 to −1.4; p<0.001) and −4.1 percent (−7.1 to −1.0; p=0.009).

There were no significant intergroup differences in systolic or diastolic blood pressure. However, heart rate was higher in patients receiving phentermine plus SOC at all time points.

Given the present data and phentermine’s long track record without major safety concerns, the norepinephrine reuptake inhibitor is a viable treatment option for paediatric obesity.

Further investigation should be conducted regarding the efficacy of phentermine as a monotherapy or in combination with other medications in paediatric obesity, researchers said. Future clinical trials should explore potential mechanisms of action and predictors of response, as well as include additional endpoints such as changes in cardiometabolic risk factors, quality of life and noninvasive vascular measurements.