Utilization of Low‐Dose Phentermine for Weight Loss Prior to Metabolic and Bariatric Surgery: A Prospective, Randomized, and Placebo‐Controlled Trial

Abstract

ABSTRACT Introduction: Studies examining preoperative weight loss using pharmacotherapy in metabolic and bariatric patients are limited. The objective was to investigate if patients taking a low‐dose formulation of phentermine had improved weight loss.

Methods: This study was a randomized, placebo‐controlled trial including patients undergoing laparoscopic Roux‐en‐Y gastric bypass and sleeve gastrectomy. Anthropometric and serological data were collected during the initial consult visit and again during two follow‐up visits. Lomaira is a low‐dose formulation of phentermine. Patients took 8‐mg tablets three times a day for 14 weeks. The primary outcome of this study was weight loss, which was measured as percentage total weight loss (%TWL) and change in body mass index (BMI).

Results: Among 53 participants randomized, 45 (85%) completed the trial. Participants were predominantly female (91%); the mean age was 41 years (SD = 11); and the mean initial BMI was 48.4 kg/m2 (SD = 8.2 kg/m2). Average weight loss was 6.2 kg (SD = 6) in the treatment group versus 1.1 kg (SD = 4.54) in the placebo group (p = 0.001). Average % TWL was greater in treatment Group 4.7 ± 4.3 versus placebo Group 1.1 ± 3.6, p = 0.001. Multivariate regression analysis demonstrated that preoperative medication use was significantly associated with greater %TWL (p = 0.004). There was no difference in OR time or post‐operative complications between the groups.

Conclusions: Low‐dose phentermine is efficacious and safe for preoperative weight loss in patients undergoing metabolic and bariatric surgery.