Background: Weight loss results in hormonal adaptations which increase hunger and cause weight regain.  Combination pharmacotherapy with Phentermine and Topiramate (Ph/T) suppresses appetite and may assist with maintenance of lost weight.

Objectives: To investigate the tolerability, adverse effect profile and efficacy of combination Ph/T in patients at a tertiary hospital obesity clinic. 

Methods: A retrospective audit was conducted of patients at the Austin Weight Control Clinic, prescribed Ph/T (15 mg Ph and 25 mg T mane) from January 2010 to July 2012, who had achieved substantial weight loss using a modified VLED approach.  Demographics, weights, blood pressure measurements and qualitative data were collected and analysed to determine cessation rates, reasons for cessation and mean weight loss during Ph/T.

Results: 103 patients were analysed.  61 patients ceased combination pharmacotherapy with 52 (50%) reporting adverse effects including parasthaesia, cognitive changes, dry mouth and depression.  The mean duration of pharmacotherapy in the total cohort was 11 months.  Weight was successfully maintained with a mean weight loss of 15.5 kg (11%) from initial to last observations.  30 patients have continued using pharmacotherapy for a mean duration of 22 months with an additional mean weight loss of 7%.

Conclusions: Ph/T (15/25 mg) is not well tolerated with high cessation rates due to adverse effects largely due to topiramate.  However, Ph/T is effective in weight maintenance and in assisting further weight loss in those able to continue with pharmacotherapy.