Date of Award


Degree Type

Selective Evidence-Based Medicine Review

Degree Name

Master of Science in Health Sciences - Physician Assistant


Physician Assistant Studies


Objective: The objective of this selective EBM review is to determine whether or not “Is phentermine/topiramate ER with lifestyle modifications effective in achieving weight loss in obese patients with comorbidities?”

Study Design: A systematic review of three placebo-controlled randomized controlled trials (RCTs) published in English in 2012 or after.

Data Sources: All three studies were found by searching PubMed and were published in peer-reviewed journals. The articles were selected based on ability to answer the proposed question.

Outcome Measured: Percent weight loss was the outcome measured in all three studies. This was measured based on mean percent weight loss from baseline at various weekly intervals.

Results: Aronne, et al, conducted a double-blind RCT that showed phentermine/topiramate (PHEN/TPM ER) 15/92 mg produced greater percent weight loss at every 4 weeks than the placebo group (p < 0.05) with LS mean percent weight loss of -11.63 compared to placebo at -2.28 for mITT analysis. 8 The ITT-LOCF analysis showed LS mean percent weight loss of -1.71 for the placebo and -9.21 for PHEN/TPM ER (p < 0.05). 8 The Winslow, et al double-blind RCT found a LS mean percent weight loss from baseline of -10.3% (standard error 1.17) for PHEN/TPM ER and -4.2% (standard error 1.15) for placebo (p = 0.0006). 9 Garvey, et al’s double-blind RCT showed that PHEN/TPM ER produced a LS mean percent weight loss of 12.1% and the placebo group only achieved 2.5% (ITT-MI; p = 0.0001). 10

Conclusion: The three studies in this review found PHEN/TPM ER to produce greater weight loss that was statistically significant when compared to placebo. This demonstrates the utility of PHEN/TPM ER in helping patients achieve weight loss and subsequently reduce the prevalence or risk of obesity-related comorbidities. Further research should be conducted to assess the role lifestyle modifications play in the success of PHEN/TPM ER and to determine its effectiveness in adolescents.