Obesity pillars roundtable: Phentermine – Past, present, and future

Effects of phentermine / topiramate extended-release, phentermine, and placebo on ambulatory blood pressure monitoring in adults with overweight or obesity: A randomized, multicenter, double-blind study

“…ABPM data on BP collected in this study provide a more comprehensive assessment of blood pressure control throughout the day and night, remove artifacts associated with white coat hypertension, and correlate more strongly with CV risk than spot measurements obtained in-clinic [16] . Moreover, control groups for this study include both placebo and phentermine 30 mg, with phentermine 30 mg being a widely used short term treatment for obesity despite little information regarding blinded, controlled clinical trial effects on blood pressure and heart rate [ 8 ]. Another strength is that the participant population for this study is representative of patients using PHEN/TPM commercially.…”

“…The other component of PHEN/TPM is phentermine, which is a sympathomimetic agent. Phentermine as monotherapy is typically used at a higher dose (30 mg) than is found in PHEN/TPM, and is contraindicated in patients with cardiovascular disease or uncontrolled hypertension [ 8 ]. Moreover, the effects of higher dose phentermine monotherapy on blood pressure have not been reported in controlled trials, potentially raising concerns about a potential increase in blood pressure with higher dose phentermine monotherapy.…”

Obesity management for cardiovascular disease prevention

“…However, short term observational studies disproved these theoretical negative cardiovascular effects, leading to its approval for short term use [ 53 ]. Phentermine is contraindicated in patients with CVD particularly in patients with high-risk conditions such asprior coronary artery bypass grafting (CABG) or stenting, history of congestive heart failure, stroke, arrhythmias, congestive heart failure [ 54 ]. Although some studies demonstrated safety of long term (>3 months) phentermine use for “low CVD risk patients”, they excluded patients with diagnoses or procedure codes for any cardiovascular outcome including MI, stroke, angina, CABG or carotid artery procedure [ 55 ].…”

Obesity and hypertension: Obesity medicine association (OMA) clinical practice statement (CPS) 2023

“…Phentermine is a sympathomimetic amine with adrenergic effects that is contraindicated in patients with cardiovascular disease (e.g., coronary artery disease, stroke, cardiac dysrhythmias, congestive heart failure, uncontrolled hypertension) [ 150 ]. In a 28 week study designed to evaluate phentermine/topiramate and its components, the phentermine 15 mg per day group experienced a placebo corrected 5% weight reduction, 1.7% systolic blood pressure reduction, and a 0.2% diastolic blood pressure reduction [ 151 ] This study is limited in that it was only 28 weeks (not a full year) and because the dose evaluated was phentermine 15 mg per day (with a more common prescribed dose being 37.5 mg per day) [ 141 ].…”