Pharmacotherapy for adults with overweight and obesity: a systematic review and network meta-analysis of randomised controlled trials

BACKGROUND

Pharmacotherapy provides an option for adults with overweight and obesity to reduce their bodyweight if lifestyle modifications fail. We summarised the latest evidence for the benefits and harms of weight-lowering drugs.

METHODS

This systematic review and network meta-analysis included searches of PubMed, Embase, and Cochrane Library (CENTRAL) from inception to March 23, 2021, for randomised controlled trials of weight-lowering drugs in adults with overweight and obesity. We performed frequentist random-effect network meta-analyses to summarise the evidence and applied the Grading of Recommendations Assessment, Development, and Evaluation frameworks to rate the certainty of evidence, calculate the absolute effects, categorise interventions, and present the findings. The study was registered with PROSPERO, CRD 42021245678.

FINDINGS

14 605 citations were identified by our search, of which 132 eligible trials enrolled 48 209 participants. All drugs lowered bodyweight compared with lifestyle modification alone; all subsequent numbers refer to comparisons with lifestyle modification. High to moderate certainty evidence established phentermine-topiramate as the most effective in lowering weight (odds ratio [OR] of ≥5% weight reduction 8·02, 95% CI 5·24 to 12·27; mean difference [MD] of percentage bodyweight change -7·98, 95% CI -9·27 to -6·69) followed by GLP-1 receptor agonists (OR 6·33, 95% CI 5·00 to 8·00; MD -5·79, 95% CI -6·34 to -5·25). Naltrexone-bupropion (OR 2·69, 95% CI 2·10 to 3·44), phentermine-topiramate (2·40, 1·68 to 3·44), GLP-1 receptor agonists (2·22, 1·74 to 2·84), and orlistat (1·71, 1·42 to 2·05) were associated with increased adverse events leading to drug discontinuation. In a post-hoc analysis, semaglutide, a GLP-1 receptor agonist, showed substantially larger benefits than other drugs with a similar risk of adverse events as other drugs for both likelihood of weight loss of 5% or more (OR 9·82, 95% CI 7·09 to 13·61) and percentage bodyweight change (MD -11·40, 95% CI -12·51 to -10·29).

INTERPRETATION

In adults with overweight and obesity, phentermine-topiramate and GLP-1 receptor agonists proved the best drugs in reducing weight; of the GLP-1 agonists, semaglutide might be the most effective.

FUNDING

1.3.5 Project for Disciplines of Excellence, West China Hospital, Sichuan University.

Comparison of the Efficacy of Anti-Obesity Medications in Real-World Practice

Purpose

Anti-obesity medications (AOMs), along with lifestyle interventions, are effective means of inducing and maintaining weight loss in patients with obesity. Although the efficacy of AOMs has been reported, there have been no direct comparisons of these drugs. Therefore, in the present study, we aimed to compare the efficacy of all the AOMs available in Korea in a real-world setting.

Patients and Methods

The body weight and composition of 205 adults treated with phentermine, phentermine/topiramate, liraglutide, naltrexone/bupropion, lorcaserin, or orlistat for at least 6 months were analyzed at 2 month intervals. The prevalence of the achievement of a ≥5% weight loss and the changes in body composition were compared between participants using each AOM at each visit.

Results

A total of 132 (64.4%) participants achieved ≥5% weight loss within 6 months (prevalence of ≥5% weight loss after 6 months: phentermine, 87.2%; phentermine/topiramate, 67.7%; liraglutide, 58.1%; naltrexone/bupropion, 35.3%; lorcaserin, 75%; orlistat, 50%). At each visit, after adjustment for age, sex, and baseline body weight, phentermine use was associated with a significantly higher prevalence of ≥5% weight loss than the use of the other AOMs, except for liraglutide. There were significant differences in the body weight, body mass index and body fat mass among the AOM groups by visit (P for interaction <0.05), but not in their waist circumference, skeletal muscle mass, percentage body fat, or visceral fat area.

Conclusion

All the AOMs were effective at inducing and maintaining weight loss, in the absence of significant changes in muscle mass, over a 6 month period, and the short-term use of phentermine and the long-term use of phentermine/topiramate or liraglutide would be practical choices for the treatment of obesity. However, further, large-scale studies are necessary to confirm these findings.

Real-World Experience of the Efficacy and Safety of Phentermine Use in Adolescents: A Case Series

Background: Pharmacotherapy has emerged as a practical option for weight management in pediatrics. This study aims to assess the effectiveness and safety of phentermine use in pediatric patients with obesity. Methods: We performed a retrospective single-center analysis of patients younger than or equal to 18 years of age, over 10 years, who underwent phentermine treatment and recommended lifestyle changes. We evaluated efficacy by the change in the percent of the 95th percentile for BMI (%BMIp95). We deemed a 5% decrease in %BMIp95 as a favorable outcome. Results: We identified 30 pediatric patients who were treated with phentermine. The cohort was primarily female, 63% white, with a mean (standard deviation) baseline age of 15.63 (1.97) years. The average duration of treatment was 10 months, with a period ranging from 2 weeks to 2 years. The average %BMIp95 at the start of treatment was 137%, and that at the time of analysis was 122%, with a mean reduction of 15%. Five patients, 17%, experienced side effects that resolved after dose reduction or discontinuing phentermine. Conclusions: Phentermine monotherapy is an effective and safe means for weight loss in pediatric patients when combined with lifestyle interventions. Twenty-one of 30 (70%) patients achieved at least a 5% decrease in %BMIp95 within a mean duration of treatment of 10 months. We noted no severe adverse events.

Potential drug-drug interactions with phentermine among long-term phentermine consumers: A retrospective analysis

BACKGROUND

Phentermine is an internationally recognised amphetamine derivative with significant appetite-suppressing properties. The drug is indicated for the short-term management of obesity, as the long-term (LT) use of phentermine may potentially be associated with severe cardiovascular side-effects, abuse and dependence. The LT use hereinafter describes periods exceeding 12 consecutive weeks. This use may also be associated with potential drug-drug interactions (PDDIs), which may result in adverse drug reactions (ADRs). The literature reports that phentermine is often prescribed LT and for several other off-label indications, increasing the risk for individuals to experience adverse drug events (ADEs) and drug-drug interactions (DDIs). There are, to our knowledge, no South African (SA) studies investigating the prevalence of co-prescribing LT phentermine with drugs that may potentially cause DDIs.

OBJECTIVE

To determine the prevalence of mild, moderate and severe DDIs with phentermine use when the duration of therapy in private healthcare exceeded 12 consecutive weeks.

METHODS

A cross-sectional drug utilisation review (DUR) was done by using data obtained from a SA pharmacy benefit management (PBM) company's database. Retrospective data of medicine claims for phentermine, from 1  January 2015 to 31  December 2019, were extracted for analysis. The number of days phentermine was supplied was used to identify the study population, in other words, those patients who received the drug LT. A drug interaction checker (Drugs.com) was used to identify potential mild, moderate and severe DDIs when using phentermine and co-prescribed drugs concurrently.

RESULTS

A total of 889 patients received phentermine LT. The top 20 drugs identified as being frequently co-prescribed in this study population demonstrated no mild PDDI, 15 (75%) moderate PDDIs and 5 (25%) severe PDDIs. The most common co-prescribed drug in the moderate group was dextromethorphan (n=282, 31.72%) and the least co-prescribed was formoterol (n=52, 5.85%). Among the drug group 'severe PDDIs', tramadol (n=416, 46.79%) was most frequently prescribed, whereas phenylpropanolamine (n=69, 7.76%) was the least prescribed to patients in this group.

CONCLUSION

There are patients who receive LT phentermine therapy despite the potential severe consequences that may result. These patients may receive concomitant therapy with phentermine and other pharmaceutical constituents, which may potentially cause DDIs, more specifically, moderate and severe DDIs. As such, these patients are not only confronted with the consequences of DDIs but are also at risk to experience ADRs as the residual effect of PDDIs.

Pharmacokinetic and pharmacodynamic interaction of DWP16001, a sodium-glucose cotransporter-2 inhibitor, with phentermine in healthy subjects

BACKGROUND

DWP16001, a sodium-glucose cotransporter-2 inhibitor, has shown promise for improving blood glucose control and facilitating weight loss. Co-administration with phentermine could enhance these effects. So, we aimed to evaluate the pharmacokinetic (PK) and pharmacodynamic (PD) interactions of DWP16001 and phentermine.

METHODS

We conducted a randomized, open-label, 3-treatment, 6-sequence, 3-period crossover study involving 24 healthy adults. Participants received either DWP16001 (2 mg), phentermine (37.5 mg), or a combination of both once daily for 7 days. Blood samples, urine samples, and body weights were collected to evaluate the PK and PD.

RESULTS

The PK of the combination was found to be similar to that of the monotherapy. The geometric mean ratio (GMR) of Cmax,ss, and AUCtau,ss were 0.98 and 1.00, respectively, for DWP16001, and 1.01 and 0.94, respectively, for phentermine. Co-administration did not significantly affect the 24-hour urinary glucose excretion compared to DWP16001 monotherapy, and the GMR was 0.90. Participants tended to experience greater weight loss in the combination therapy group, and all demonstrated good tolerance.

CONCLUSIONS

Our findings indicate that there were no significant interactions during co-administration. These results suggest that the combination of DWP16001 and phentermine may be safe and effective for the treatment of obesity and diabetes.

CLINICAL TRIAL REGISTRATION

NCT05321732.

Intensive management of obesity in people with Prader-Willi syndrome

PURPOSE

Prader-Willi syndrome (PWS) is characterised by childhood-onset hyperphagia and obesity however limited data are available to guide treatment of obesity in this population. We aimed to evaluate the safety, tolerability, and efficacy of intensive medical weight loss interventions (very-low-energy diets [VLED] and/or pharmacotherapy) in individuals with PWS attending a specialist obesity management service.

METHODS

A retrospective audit was undertaken of individuals with PWS attending the Austin Health Weight Control Clinic between January 2010-April 2021. Main outcome measures were weight outcomes, duration of use, and adverse effects.

RESULTS

Data were available for 18 patients, of whom 15 were treated with intensive weight loss interventions. Median (interquartile range, IQR) age at baseline was 20 years (19-32) with median body weight 90 kg (75-118) and BMI 37 kg/m² (30-51). Median weight loss during VLED (n = 7) was 14 kg (1-20 kg) over 60 weeks. Median weight loss with phentermine-topiramate (n = 7) was 17 kg (IQR 9-19 kg) over 56 weeks. Median weight loss with liraglutide 0.6-3 mg (n = 7), prescribed with topiramate in 3 individuals, was 9 kg (2-14 kg) over 96 weeks. Naltrexone-bupropion resulted in weight loss in 2 of 4 individuals. Thirteen individuals achieved ≥10% weight loss but only 5 individuals maintained ≥10% weight loss at last follow-up. Five individuals discontinued pharmacotherapy due to adverse effects.

CONCLUSIONS

VLED and pharmacotherapy can achieve substantial weight loss in some individuals with PWS though non-adherence results in substantial weight regain. Adverse effects were ascribed to phentermine and topiramate, whereas liraglutide was well-tolerated in this population.

Effect of Phentermine on Hepatic Steatosis in Bariatric Surgery: A Pilot Study

OBJECTIVE

Hepatic steatosis is associated with increased surgical complications in bariatric surgery patients. We aimed to evaluate the effect of phentermine in reducing hepatic steatosis, adipose tissue, and surgical complications in patients undergoing bariatric surgery.

METHODS

This was a two-arm, double-blind, randomized, controlled pilot trial of 64 adult subjects with BMI >35 kg/m2 selected for bariatric surgery randomized into phentermine group (15 mg once daily) or placebo group for 8 weeks. Both groups adhered to a hypocaloric diet (500 calories/day) and an individualized exercise program. The primary endpoint was reducing the frequency of hepatic steatosis measured by ultrasound and reducing adipose tissue through fat mass in total kilograms or percentage. Key secondary points were the prevalence of surgical complications. Baseline and final biochemical parameters and blood pressure too were assessments.

RESULTS

In the phentermine group, the frequency of hepatic steatosis decreased by 19%, and the percentage of patients with a normal ultrasound increased from 9% to 28% (p = 0.05). Likewise, the decrease in fat mass in kilograms was more significant in the phentermine group (56.1 kg vs. 51.8 kg, p = 0.02). A significant reduction in the HOMA-IR index was observed regardless of weight loss. No differences in surgical complications were observed between groups. Phentermine was well-tolerated; no differences were observed in the frequency of adverse events between the groups.

CONCLUSIONS

Phentermine decreased the proportion of individuals with hepatic steatosis by 19% and promoted a more significant fat mass loss in kilograms among candidates for bariatric surgery.

Efficacy and Safety of Phentermine/Topiramate in Adults with Overweight or Obesity: A Systematic Review and Meta-Analysis

OBJECTIVE

The study objective was to examine the association between phentermine/topiramate therapy and weight loss and adverse events in adults with overweight or obesity by meta-analysis and systematic review.

METHODS

Medical Subject Headings and free-text terms were selected to search for eligible trials in PubMed, Cochrane Central Register of Controlled Trials (CENTRAL), and Embase up to April 18, 2020. The quality of randomized controlled trials was evaluated by the Cochrane risk-of-bias tool. Meta-analysis was performed using random-effect models.

RESULTS

Phentermine/topiramate therapy resulted in an average weight loss of 7.73 kg (95% CI: 6.60-8.85) in general compared with placebo. The weight loss was related to the dose of phentermine/topiramate. Compared with placebo, the average weight loss was 3.55 kg (95% CI: 2.22-4.88) for 3.75/23 mg, 7.27 kg (95% CI: 6.40-8.13) for 7.5/46 mg, and 8.25 kg (95% CI: 6.92-9.79) for 15/92 mg. For phentermine/topiramate participants in different weight-loss subgroups, the weight loss of participants with ≥5%, ≥10%, and ≥15% baseline weight loss was 3.18 (95% CI: 2.75-3.67), 5.32 (95% CI: 4.53-6.25), and 5.65 (95% CI: 3.55-9.01), respectively. Compared with placebo, the adverse events associated with the treatment mainly included dysgeusia (odds ratio [OR] = 8.86, 95% CI: 5.65-13.89), paresthesia (OR = 8.51, 95% CI: 6.20-11.67), dry mouth (OR = 6.71, 95% CI: 5.03-8.94), disturbance in attention (OR = 4.48, 95% CI: 2.39-8.41), irritability (OR = 4.10, 95% CI: 2.29-7.33), hypoesthesia (OR = 3.81, 95% CI: 1.32-11.00), constipation (OR = 2.43, 95% CI: 2.02-2.93), and dizziness (OR = 2.26, 95% CI: 1.72-2.98). Phentermine/topiramate also reduced waist circumference, blood pressure, blood sugar levels, and lipid levels.

CONCLUSIONS

Phentermine/topiramate has considerable benefit in reducing body weight, and the efficacy was closely related to the dosage. However, it increased the risk of nervous system-related adverse events.

Long-term effects of weight-reducing drugs in people with hypertension

BACKGROUND

This is the third update of this review, first published in July 2009. All major guidelines on treatment of hypertension recommend weight loss; anti-obesity drugs may be able to help in this respect.

OBJECTIVES

Primary objectives: To assess the long-term effects of pharmacologically-induced reduction in body weight in adults with essential hypertension on all-cause mortality, cardiovascular morbidity, and adverse events (including total serious adverse events, withdrawal due to adverse events, and total non-serious adverse events).. Secondary objectives: To assess the long-term effects of pharmacologically-induced reduction in body weight in adults with essential hypertension on change from baseline in systolic and diastolic blood pressure, and on body weight reduction.

SEARCH METHODS

For this updated review, the Cochrane Hypertension Information Specialist searched the following databases for randomised controlled trials up to March 2020: the Cochrane Hypertension Specialised Register, CENTRAL, MEDLINE (from 1946), Embase (from 1974), the World Health Organization International Clinical Trials Registry Platform, and ClinicalTrials.gov. The searches had no language restrictions. We contacted authors of relevant papers about further published and unpublished work.

SELECTION CRITERIA

Randomised controlled trials of at least 24 weeks' duration in adults with hypertension that compared approved long-term weight-loss medications to placebo.  DATA COLLECTION AND ANALYSIS: Two review authors independently selected studies, assessed risks of bias, and extracted data. Where appropriate and in the absence of significant heterogeneity between studies (P > 0.1), we pooled studies using a fixed-effect meta-analysis. When heterogeneity was present, we used the random-effects method and investigated the cause of the heterogeneity.

MAIN RESULTS

This third update of the review added one new trial, investigating the combination of naltrexone/bupropion versus placebo. Two medications, which were included in the previous versions of this review (rimonabant and sibutramine) are no longer considered relevant for this update, since their marketing approval was withdrawn in 2010 and 2009, respectively. The number of included studies in this review update is therefore six (12,724 participants in total): four RCTs comparing orlistat to placebo, involving a total of 3132 participants with high blood pressure and a mean age of 46 to 55 years; one trial comparing phentermine/topiramate to placebo, involving 1305 participants with high blood pressure and a mean age of 53 years; and one trial comparing naltrexone/bupropion to placebo, involving 8283 participants with hypertension and a mean age of 62 years. We judged the risks of bias to be unclear for the trials investigating orlistat or naltrexone/bupropion. and low for the trial investigating phentermine/topiramate. Only the study of naltrexone/bupropion included cardiovascular mortality and morbidity as predefined outcomes. There were no differences in the rates of all-cause or cardiovascular mortality, major cardiovascular events, or serious adverse events between naltrexone/bupropion and placebo. The incidence of overall adverse events was significantly higher in participants treated with naltrexone/bupropion. For orlistat, the incidence of gastrointestinal side effects was consistently higher compared to placebo. The most frequent side effects with phentermine/topiramate were dry mouth and paraesthesia. After six to 12 months, orlistat reduced systolic blood pressure compared to placebo by mean difference (MD) -2.6 mm Hg (95% confidence interval (CI) -3.8 to -1.4 mm Hg; 4 trials, 2058 participants) and diastolic blood pressure by MD -2.0 mm Hg (95% CI -2.7 to -1.2 mm Hg; 4 trials, 2058 participants). After 13 months of follow-up, phentermine/topiramate decreased systolic blood pressure compared to placebo by -2.0 to -4.2 mm Hg (1 trial, 1030 participants) (depending on drug dosage), and diastolic blood pressure by -1.3 to -1.9 mm Hg (1 trial, 1030 participants) (depending on drug dosage). There was no difference in the change in systolic or diastolic blood pressure between naltrexone/bupropion and placebo (1 trial, 8283 participants). We identified no relevant studies investigating liraglutide or lorcaserin in people with hypertension.

AUTHORS' CONCLUSIONS

In people with elevated blood pressure, orlistat, phentermine/topiramate and naltrexone/bupropion reduced body weight; the magnitude of the effect was greatest with phentermine/topiramate. In the same trials, orlistat and phentermine/topiramate, but not naltrexone/bupropion, reduced blood pressure. One RCT of naltrexone/bupropion versus placebo showed no differences in all-cause mortality or cardiovascular mortality or morbidity after two years. The European Medicines Agency refused marketing authorisation for phentermine/topiramate due to safety concerns, while for lorcaserin the application for European marketing authorisation was withdrawn due to a negative overall benefit/risk balance. In 2020 lorcaserin was also withdrawn from the US market. Two other medications (rimonabant and sibutramine) had already been withdrawn from the market in 2009 and 2010, respectively.

A Retrospective Study Examining Phentermine on Preconception Weight Loss and Pregnancy Outcomes

OBJECTIVE

Obesity is a well-known risk factor for infertility. However, the use of weight loss medications prior to conception is underutilized. The objectives of our study are to describe weight loss, pregnancy rates, and live birth rates after short-term phentermine use in women with obesity and infertility.

METHODS

This was a retrospective analysis of 55 women (18 to 45 years old) who were overweight or obese, diagnosed with infertility, and prescribed phentermine for weight loss in an ambulatory endocrinology clinic at a single, tertiary level academic medical center. Main outcome measures were mean percent weight change at 3 months after starting phentermine, and pregnancy, and live birth rates from start of phentermine to June 30, 2017.

RESULTS

Median duration of phentermine use was 70 days (Q1, Q3 [33, 129]). Mean ± SD percent weight change at 3 months after starting phentermine was -5.3 ± 4.1% (P<.001). The pregnancy rate was 60% and the live birth rate was 49%. There was no significant difference in pregnancy rates (52% versus 68%; P = .23) or live birth rates (44% versus 54%; P = .50) in women who lost ≥5% versus <5% of their baseline weight. The number of metabolic comorbidities was negatively associated with the pregnancy rate. Phentermine was generally well-tolerated with no serious adverse events.

CONCLUSION

Phentermine can produce clinically significant weight loss in women with obesity during the preconception period. Higher pregnancy or live birth rates were not observed with a greater degree of weight loss with phentermine.

A randomized, double-blind, placebo-controlled, pharmacokinetic and pharmacodynamic study of a fixed-dose combination of phentermine/topiramate in adolescents with obesity

AIMS

To assess the pharmacokinetic (PK) and pharmacodynamic characteristics of VI-0521, a fixed-dose combination of immediate-release phentermine (PHEN) and extended-release topiramate (TPM) in adolescents aged 12 to 17 years with obesity, and to report weight loss and adverse events using this drug combination.

MATERIALS AND METHODS

This was a multicentre, randomized, double-blind, parallel-design, placebo-controlled study in adolescents with obesity. A total of 42 adolescents were randomly assigned in a 1:1:1 ratio to placebo, or to a mid-dose (PHEN/TPM 7.5 mg/46 mg), or a top-dose (PHEN/TPM 15 mg/92 mg) of VI-0521. A total of 26 adolescents were included in the PK analysis (14 from the mid-dose group and 12 from the top-dose group).

RESULTS

On day 56, arithmetic means of terminal elimination half-life, apparent clearance (CL/F) and apparent central volume of distribution (Vc/F) were consistent across dose levels for both PHEN and TPM. Arithmetic means of CL/F and Vc/F for PHEN and TPM administered as a combination in adolescents with obesity were within 10% to 30% of those previously assessed in adults with obesity enrolled in phase II and III studies. A higher proportion of adolescents in both the mid- and top-dose groups (13.3% and 50.0%, respectively) compared with placebo (0.0%) reached ≥5% weight loss at day 56. The least squares (LS) mean change in systolic blood pressure from baseline to day 56 was -5.2 mmHg for the placebo group, -2.5 mmHg for the mid-dose group, and - 5.5 mmHg for the top-dose group. The LS mean change in diastolic blood pressure from baseline to day 56 was -2.4 mmHg for the placebo group, +3.8 mmHg for the mid-dose group, and + 2.0 mmHg for the top-dose group. Participants in the top-dose group had increases in heart rate from baseline of 4.1 bpm, while participants in the mid-dose group experienced a mean decrease in heart rate of 4.5 bpm at day 56. Both PHEN/TPM dose combinations were safe and well tolerated.

CONCLUSIONS

Treatment of adolescents with obesity using a fixed-dose combination of PHEN/TPM for 8 weeks resulted in exposure to PHEN and TPM that was comparable to that observed in adults, statistically significant weight loss, and a tolerable safety profile. These data indicate that both mid- and top-dose levels are appropriate for longer-term safety and efficacy studies in adolescents.

A Medical Review of Fatal High-G U.S. Aerobatic Accidents

INTRODUCTION: Exposure to high G force is a known safety hazard in military aviation as well as civilian aerobatic flight. Tolerance to high G forces has been well studied in military pilots, but there is little research directed at civilian pilots who may have medications or medical conditions not permitted in military pilots.METHODS: In this case-control study, we identified 89 fatal high-G aerobatic accidents and 4000 fatal control accidents from 1995 through 2018 from the NTSB accident database and the FAA autopsy database. We retrieved medications and medical conditions from the FAA's pilot medical databases. Logistic regression models were used to explore the associations of drugs, medical conditions, height, and medical waivers with high-G accidents.RESULTS: Seven drugs (alprazolam, clonidine, ethanol, meclizine, phentermine, triamterene, and zolpidem) reached statistical significance in our models, but had such small case counts that we consider these findings to be uncertain, except for ethanol, which was found in seven cases. Of these, only triamterene was known to the FAA. Statistically significant medical predictors included only alcohol abuse (seven cases) and liver disease (only two cases).DISCUSSION: Our analysis found that the drug ethanol and the condition alcohol abuse are significantly associated with high-G accidents. Seven other factors were statistically significant, but should only be considered as hypothesis generating due to very low case counts. Our study does not suggest that restricting pilots with otherwise permissible medications or medical conditions from aerobatics is warranted.Mills WD, Greenhaw RM, Wang JMP. A medical review of fatal high-G U.S. aerobatic accidents. Aerosp Med Hum Perform. 2019; 90(11):959-965.

Effects of liraglutide plus phentermine in adults with obesity following 1 year of treatment by liraglutide alone: A randomized placebo-controlled pilot trial

BACKGROUND

This pilot study evaluated whether adding phentermine to liraglutide would induce further weight loss in participants who had previously lost weight with liraglutide alone.

SUBJECTS/METHODS

Participants were 45 adults with obesity (75.6% female, 55.6% white, body mass index = 34.3 ± 4.7 kg/m²) who had lost an average of 12.6 ± 6.8% of initial weight during a prior 1-year randomized trial with liraglutide and intensive behavioral treatment. Participants were re-randomized, in a double-blinded fashion, to liraglutide 3.0 mg plus phentermine 15.0 mg (liraglutide-phentermine) or liraglutide plus placebo (liraglutide-placebo). Participants also were provided with four, 15-minute counseling sessions during the 12-week extension study.

RESULTS

At week 12, the liraglutide-phentermine and liraglutide-placebo groups lost a mean (±SEM) of 1.6 ± 0.6% and 0.1 ± 0.5% of re-randomization weight, respectively (p = 0.073). Two (9.1%) liraglutide-phentermine participants and one (4.3%) liraglutide-placebo participant lost ≥5% of re-randomization weight; 19 (86.4%) and 16 (69.9%) participants, respectively, maintained their full weight loss achieved in the prior 1-year trial (p = 0.125). Liraglutide-phentermine participants generally reported larger reductions in hunger and food preoccupation than liraglutide-placebo participants during the first 8 weeks of the extension study.

CONCLUSIONS

The combination of liraglutide and phentermine appeared to be well-tolerated but did not produce additional clinically meaningful weight loss in individuals who had already lost 12.6% of initial weight with liraglutide alone.

TRIAL REGISTRATION

ClinicalTrials.gov number, NCT02911818.

Phentermine and Coronary Vasospasm-Induced Myocardial Infarction

Women presenting to the cardiac catheterization laboratory with normal coronary arteries without significant atherosclerotic disease is a common presentation. In such patients, it is important to maintain a wide differential and consider alternate diagnoses. We present two cases of women presenting with chest pain found to have severe coronary vasospasm in the setting of recent initiation of phentermine. Phentermine may have vasospastic proprieties which are important to consider when prescribing to patients.

Cardiovascular Safety During and After Use of Phentermine and Topiramate

CONTEXT

Increases in heart rate were seen during the clinical program for fixed-dose combination phentermine (PHEN) and topiramate (TPM), an oral medication indicated for weight management; however, the effect on cardiovascular (CV) outcomes is uncertain.

OBJECTIVE

The aim of the present study was to determine the extent to which the rates of major adverse CV events (MACE) in patients using PHEN and TPM (including fixed dose) differed from the MACE rates during unexposed periods.

DESIGN

Retrospective cohort study.

SETTING

MarketScan, US insurance billing data.

PATIENTS OR OTHER PARTICIPANTS

Patients aged >18 years with ≥6 months of continuous enrollment in the database before taking PHEN and/or TPM or after stopping these medications.

INTERVENTIONS

PHEN and TPM, taken separately and together (including fixed dose).

MAIN OUTCOME MEASURES

MACE, a composite of hospitalization for acute myocardial infarction and stroke and in-hospital CV death.

RESULTS

Because the outcomes are rare and the duration of medication use was brief, few events occurred. The MACE rates among current users of PHEN/TPM, fixed-dose PHEN/TPM, and PHEN were lower than those among unexposed former users. In contrast, the rate of MACE among current users of TPM was greater than among unexposed former users [incidence rate ratio: PHEN/TPM, 0.57; 95% CI, 0.19 to 1.78; fixed-PHEN/TPM, 0.24; 95% CI, 0.03 to 1.70; PHEN, 0.56; 95% CI, 0.34 to 0.91; TPM, 1.58; 95% CI, 1.33 to 1.87).

CONCLUSIONS

Overall, the data indicated no increased risk of MACE for current PHEN/TPM users; however, the 95% CIs for the PHEN/TPM groups were broad, indicating that the data were compatible with a wide range of possible values.

A randomized, double-blind, placebo-controlled, crossover study to evaluate the human abuse liability of solriamfetol, a selective dopamine and norepinephrine reuptake inhibitor

BACKGROUND

This study evaluated the human abuse potential of solriamfetol (formerly JZP-110), a selective dopamine and norepinephrine reuptake inhibitor with robust wake-promoting effects.

METHODS

Adults with a recent history of recreational polydrug use, including stimulants, and who met criteria in a Qualification Phase were randomized to one of six sequences in a Test Phase. Each Test Phase sequence included a single administration of placebo, solriamfetol (300, 600, and 1200 mg), and phentermine (45 and 90 mg), with a two-day washout between periods. The primary endpoint was peak rating ( Emax) of Liking at the Moment across the first 12 h on a liking/disliking visual analog scale; key secondary endpoints were Next Day Overall Drug Liking, how much the participant would like to Take the Drug Again, and positive and negative subjective effects. Safety was also assessed throughout the study.

RESULTS

Of 43 participants (74.4% male; mean age 29.3 years), 37 completed the study. Peak Emax Liking at the Moment for all solriamfetol doses was significantly greater than placebo and significantly less than phentermine 90 mg ( p < 0.05). Overall Next Day Drug Liking was greater than placebo for solriamfetol 300 mg and phentermine 45 and 90 mg ( p < 0.05). Willingness to Take the Drug Again was significantly greater than placebo and significantly less than both doses of phentermine for all doses of solriamfetol ( p < 0.05). Ratings of negative subjective effects (bad effects, disliking, anxiety, agitation) were higher with solriamfetol 600 and 1200 mg relative to phentermine. The most common treatment-emergent adverse events with solriamfetol were hypervigilance, elevated mood, dry mouth, hyperhidrosis, and insomnia.

CONCLUSION

Solriamfetol appears to have abuse potential similar to or lower than phentermine.

Study protocol and rationale for a randomized double-blinded crossover trial of phentermine-topiramate ER versus placebo to treat binge eating disorder and bulimia nervosa

INTRODUCTION

Bulimia nervosa (BN) and binge eating disorder (BED) are associated with severe psychological and medical consequences. Current therapies are limited, leaving up to 50% of patients symptomatic despite treatment, underscoring the need for additional treatment options. Qsymia, an FDA-approved medication for obesity, combines phentermine and topiramate ER. Topiramate has demonstrated efficacy for both BED and BN, but limited tolerability. Phentermine is FDA-approved for weight loss. A rationale for combined phentermine/topiramate for BED and BN is improved tolerability and efficacy. While a prior case series exploring Qsymia for BED showed promise, randomized studies are needed to evaluate Qsymia's safety and efficacy when re-purposed in eating disorders. We present a study protocol for a Phase I/IIa single-center, prospective, double-blinded, randomized, crossover trial examining safety and preliminary efficacy of Qsymia for BED and BN.

METHODS

Adults with BED (n=15) or BN (n=15) are randomized 1:1 to receive 12weeks Qsymia (phentermine/topiramate ER, 3.75mg/23mg-15mg/92mg) or placebo, followed by 2-weeks washout and 12-weeks crossover, where those on Qsymia receive placebo and vice versa. Subsequently participants receive 8weeks follow-up off study medications. The primary outcome is the number of binge days/week measured by EDE. Secondary outcomes include average number of binge episodes, percentage abstinence from binge eating, and changes in weight/vitals, eating psychopathology, and mood.

DISCUSSION

To our knowledge this is the first randomized, double-blind protocol investigating the safety and efficacy of phentermine/topiramate in BED and BN. We highlight the background and rationale for this study, including the advantages of a crossover design.

TRIAL REGISTRATION

Clinicaltrials.gov identifier NCT02553824 registered on 9/17/2015. https://clinicaltrials.gov/ct2/show/NCT02553824.

Cardiovascular safety of low-dose fenfluramine in Dravet syndrome: a review of its benefit-risk profile in a new patient population

OBJECTIVE

Dravet syndrome (DS) is a rare, treatment-resistant epilepsy syndrome for which current treatment regimens are often ineffective. Fenfluramine is currently in development for treatment of DS, based on reports in the 1980s and 1990s of its anti-epileptic activity in pediatric patients with intractable epilepsy. However, fenfluramine was withdrawn from global markets in 1997 following reports of its association with pulmonary hypertension and heart valve disease in adult patients treated for obesity. This review was conducted to assess cardiac safety of fenfluramine when used at lower doses for treatment of DS.

METHODS

Pubmed was searched for clinical studies of fenfluramine in obese adults who reported incidence of heart valve disease. These data were reviewed against published results from Belgian patients with DS who have been treated with low-dose fenfluramine for up to 28 years.

RESULTS

Nine controlled studies of fenfluramine and related compounds (dexfenfluramine and/or phentermine) which assessed incidence and severity of cardiac valve disease in 3,268 treated patients and 2,017 control subjects have been reported. Mild or greater aortic valve regurgitation was found in 9.6% of treated patients compared with 3.9% of control subjects, and moderate or greater mitral valve regurgitation was found in 3.1% of treated patients and 2.5% of control subjects. Nineteen DS patients have been treated for up to 28 years with 10-20 mg/day fenfluramine, with no clinical signs or symptoms of cardiac valve disease or pulmonary hypertension. Slight and clinically unimportant changes in valve structure have been seen on echocardiography in five patients at some time during the observation period.

CONCLUSIONS

A different benefit-risk relationship appears to be emerging when fenfluramine is used at low doses for extended periods in young patients with DS. Continued cardiac assessments during ongoing Phase 3 clinical trials will provide additional safety information for this potential new and effective treatment.

Obesity Epidemic: Pharmaceutical Weight Loss

Obesity is a chronic disease universally defined as an excess of adipose tissue resulting in body mass index (BMI) > 30.0 kg/m2. Over the past few years, the concept of prevention has gained increased awareness, thus leading to the development of additional pharmaceutical options for the treatment of obesity since 2012. Treating obesity revolves around an individualized, multi-disciplinary approach with additional focus on a healthy and supportive lifestyle to maintain the weight loss. [Full article available at http://rimed.org/rimedicaljournal-2017-03.asp].

Pharmacotherapy for obesity

BACKGROUND

Obesity is a serious, chronic, relapsing disease of energy regulation, with strong genetic and early-life environmental determinants. Pharmacotherapy can be a useful adjunct to lifestyle intervention in effecting and maintaining clinically meaningful weight loss.

OBJECTIVE

The aim of this article is to discuss the role of pharmacotherapy in obesity management. The efficacy, side effects and contraindications of available weight-loss medications are reviewed.

DISCUSSION

Long-term pharmacotherapy options, which can be effective in providing moderate weight loss, are available to treat obesity. Pharma-cotherapy should be considered an adjunct to lifestyle intervention in those with a body mass index (BMI) >30 kg/m30 kg/m2, or in those with a BMI of 27-30 kg/m2 and obesity-related complications. Safety and efficacy should be monitored closely on commencement, and the medication should be discontinued if there are safety or tolerability issues, or if.

Association of Pharmacological Treatments for Obesity With Weight Loss and Adverse Events: A Systematic Review and Meta-analysis

IMPORTANCE

Five medications have been approved for the management of obesity, but data on comparative effectiveness are limited.

OBJECTIVE

To compare weight loss and adverse events among drug treatments for obesity using a systematic review and network meta-analysis.

DATA SOURCES

MEDLINE, EMBASE, Web of Science, Scopus, and Cochrane Central from inception to March 23, 2016; clinical trial registries.

STUDY SELECTION

Randomized clinical trials conducted among overweight and obese adults treated with US Food and Drug Administration-approved long-term weight loss agents (orlistat, lorcaserin, naltrexone-bupropion, phentermine-topiramate, or liraglutide) for at least 1 year compared with another active agent or placebo.

DATA EXTRACTION AND SYNTHESIS

Two investigators identified studies and independently abstracted data using a predefined protocol. A Bayesian network meta-analysis was performed and relative ranking of agents was assessed using surface under the cumulative ranking (SUCRA) probabilities. Quality of evidence was assessed using GRADE criteria.

MAIN OUTCOMES AND MEASURES

Proportions of patients with at least 5% weight loss and at least 10% weight loss, magnitude of decrease in weight, and discontinuation of therapy because of adverse events at 1 year.

RESULTS

Twenty-eight randomized clinical trials with 29 018 patients (median age, 46 years; 74% women; median baseline body weight, 100.5 kg; median baseline body mass index, 36.1) were included. A median 23% of placebo participants had at least 5% weight loss vs 75% of participants taking phentermine-topiramate (odds ratio [OR], 9.22; 95% credible interval [CrI], 6.63-12.85; SUCRA, 0.95), 63% of participants taking liraglutide (OR, 5.54; 95% CrI, 4.16-7.78; SUCRA, 0.83), 55% taking naltrexone-bupropion (OR, 3.96; 95% CrI, 3.03-5.11; SUCRA, 0.60), 49% taking lorcaserin (OR, 3.10; 95% CrI, 2.38-4.05; SUCRA, 0.39), and 44% taking orlistat (OR, 2.70; 95% CrI, 2.34-3.09; SUCRA, 0.22). All active agents were associated with significant excess weight loss compared with placebo at 1 year-phentermine-topiramate, 8.8 kg (95% CrI, -10.20 to -7.42 kg); liraglutide, 5.3 kg (95% CrI, -6.06 to -4.52 kg); naltrexone-bupropion, 5.0 kg (95% CrI, -5.94 to -3.96 kg); lorcaserin, 3.2 kg (95% CrI, -3.97 to -2.46 kg); and orlistat, 2.6 kg (95% CrI, -3.04 to -2.16 kg). Compared with placebo, liraglutide (OR, 2.95; 95% CrI, 2.11-4.23) and naltrexone-bupropion (OR, 2.64; 95% CrI, 2.10-3.35) were associated with the highest odds of adverse event-related treatment discontinuation. High attrition rates (30%-45% in all trials) were associated with lower confidence in estimates.

CONCLUSIONS AND RELEVANCE

Among overweight or obese adults, orlistat, lorcaserin, naltrexone-bupropion, phentermine-topiramate, and liraglutide, compared with placebo, were each associated with achieving at least 5% weight loss at 52 weeks. Phentermine-topiramate and liraglutide were associated with the highest odds of achieving at least 5% weight loss.

Colon Ischemia After Weight-Loss Medication in a 36-Year-Old Woman

Weight-loss medications have been associated with many conditions, including valvular heart disease, ischemic colitis, and pulmonary hypertension. There is a constant increase in the use of these drugs, especially new medications with better efficacy. Phentermine is one such drug, approved for short-term use to lose weight. We report a case of ischemic colitis in a female patient linked to inappropriate phentermine intake. The patient presented with symptoms of severe abdominal pain and repeated bowel movement associated with rectal bleeding for two weeks. Initial blood work was unremarkable for infectious and inflammatory causes. A CT scan was performed which revealed findings of ischemic colitis extending from transverse to descending colon. A biopsy study confirmed the same. Upon further questioning, the patient admitted to taking 37.5 mg of phentermine for two years beyond her prescribed period of 12 weeks. Hence, we propose that inappropriate use of phentermine caused ischemic colitis. With the widespread use of these medications, there is a need for heightened awareness among clinicians regarding adverse effects of phentermine.

Long-term effects of weight-reducing drugs in people with hypertension

BACKGROUND

All major guidelines on antihypertensive therapy recommend weight loss; anti-obesity drugs may be able to help in this respect.

PRIMARY OBJECTIVES

To assess the long-term effects of pharmacologically induced reduction in body weight in adults with essential hypertension on all-cause mortality, cardiovascular morbidity, and adverse events (including total serious adverse events, withdrawal due to adverse events, and total non-serious adverse events).

SECONDARY OBJECTIVES

To assess the long-term effects of pharmacologically induced reduction in body weight in adults with essential hypertension on change from baseline in systolic blood pressure, change from baseline in diastolic blood pressure, and body weight reduction.

SEARCH METHODS

We obtained studies using computerised searches of the Cochrane Hypertension Group Specialised Register, the Cochrane Central Register of Controlled Trials (CENTRAL), Ovid MEDLINE, Ovid EMBASE, the clinical trials registry ClinicalTrials.gov, and from handsearches in reference lists and systematic reviews (status as of 13 April 2015).

SELECTION CRITERIA

Randomised controlled trials in hypertensive adults of at least 24 weeks' duration that compared long-term pharmacologic interventions for weight loss with placebo. 

DATA COLLECTION AND ANALYSIS

Two review authors independently selected studies, assessed risk of bias, and extracted data. Where appropriate and in the absence of significant heterogeneity between studies (P > 0.1), we pooled studies using fixed-effect meta-analysis. When heterogeneity was present, we used the random-effects method and investigated the cause of heterogeneity.

MAIN RESULTS

After updating the literature search, which was extended to include four new weight-reducing drugs, we identified one additional study of phentermine/topiramate, bringing the total number of studies to nine that compare orlistat, sibutramine, or phentermine/topiramate to placebo and thus fulfil our inclusion criteria. We identified no relevant studies investigating rimonabant, liraglutide, lorcaserin, or naltrexone/bupropion. No study included mortality and cardiovascular morbidity as predefined outcomes. Incidence of gastrointestinal side effects was consistently higher in those participants treated with orlistat versus those treated with placebo. The most frequent side effects were dry mouth, constipation, and headache with sibutramine, and dry mouth and paresthaesia with phentermine/topiramate. In participants assigned to orlistat, sibutramine, or phentermine/topiramate body weight was reduced more effectively than in participants in the usual-care/placebo groups. Orlistat reduced systolic blood pressure as compared to placebo by -2.5 mm Hg (mean difference (MD); 95% confidence interval (CI): -4.0 to -0.9 mm Hg) and diastolic blood pressure by -1.9 mm Hg (MD; 95% CI: -3.0 to -0.9 mm Hg). Sibutramine increased diastolic blood pressure compared to placebo by +3.2 mm Hg (MD; 95% CI: +1.4 to +4.9 mm Hg). The one trial that investigated phentermine/topiramate suggested it lowered blood pressure.

AUTHORS' CONCLUSIONS

In people with elevated blood pressure, orlistat and sibutramine reduced body weight to a similar degree, while phentermine/topiramate reduced body weight to a greater extent. In the same trials, orlistat and phentermine/topiramate reduced blood pressure, while sibutramine increased it. We could include no trials investigating rimonabant, liraglutide, lorcaserin, or naltrexone/bupropion in people with elevated blood pressure. Long-term trials assessing the effect of orlistat, liraglutide, lorcaserin, phentermine/topiramate, or naltrexone/bupropion on mortality and morbidity are unavailable and needed. Rimonabant and sibutramine have been withdrawn from the market, after long-term trials on mortality and morbidity have confirmed concerns about the potential severe side effects of these two drugs. The European Medicines Agency refused marketing authorisation for phentermine/topiramate due to safety concerns, while the application for European marketing authorisation for lorcaserin was withdrawn by the manufacturer after the Committee for Medicinal Products for Human Use judged the overall benefit/risk balance to be negative.

Greater hunger and less restraint predict weight loss success with phentermine treatment

OBJECTIVE

Phentermine is thought to cause weight loss through a reduction in hunger. It was hypothesized that higher hunger ratings would predict greater weight loss with phentermine.

METHODS

This is an observational pilot study in which all subjects were treated with phentermine for 8 weeks and appetite and eating behaviors were measured at baseline and week 8. Outcomes were compared in subjects with ≥5% vs. <5% weight loss, and linear regression was used to identify predictors of percent weight loss.

RESULTS

Twenty-seven subjects (37 ± 4.5 years, 93.8 ± 12.1 kg, BMI 33.8 ± 3.1 kg m(-2) ) completed the study, with mean weight loss of -5.4 ± 3.3 kg (-5.7% ± 3.2%). Subjects with ≥5% weight loss had higher baseline pre-breakfast hunger (P = 0.017), desire to eat (P =0.003), and prospective food consumption (0.006) and lower baseline cognitive restraint (P = 0.01). In addition, higher baseline home prospective food consumption (P = 0.002) and lower baseline cognitive restraint (P < 0.001) were found to be predictors of weight loss.

CONCLUSIONS

These results suggest that individuals reporting greater hunger and less restraint are more likely to achieve significant weight loss with phentermine. This information can be used clinically to determine who might benefit most from phentermine treatment.

Subarachnoid hemorrhage in a patient taking phentermine for weight loss

OBJECTIVE

To report the case of an angiography-negative subarachnoid hemorrhage (SAH) in association with increased use of the sympathomimetic phentermine.

SUMMARY

A 45-year-old woman taking phentermine for weight loss presented with the "worst headache of her life," as well as nausea and some confusion. Her prior medical history was largely negative for pathology except for a 20-pack-year history of smoking.

RESULTS

Upon admission to an inpatient facility, the patient was normotensive with a Glasgow Coma Score of 15. She was found on computed tomography to have a diffuse SAH (Hunt and Hess grade 2, Fisher grade 3). Digital subtraction angiography, performed on hospital day 2, was negative for aneurysm. The patient convalesced in the intensive care unit for 8 days and was treated as a typical patient with SAH (i.e., vasospasm prophylaxis with nimodipine and atorvastatin, ad lib diet with strict attention to fluid balance to maintain euvolemia). A repeat angiographic study on hospital day 8 also did not reveal an aneurysm or other cause for her SAH. She was discharged thereafter with intensive smoking cessation education and counseled to discontinue phentermine. Upon follow-up 6 weeks later, the patient was without complaints or neurologic deficits and had resumed her previous activities and work.

CONCLUSION

Phentermine is a sympathomimetic agent found commonly in weight-loss products. Sympathomimetics have been linked to the development of hypertension, which can lead to cardiovascular and neurologic hemorrhages. We believe that the SAH in this patient was likely secondary to drug-induced hypertension or vasculopathy from the phentermine.

Formulary management of 2 new agents: lorcaserin and phentermine/topiramate for weight loss

BACKGROUND

Obesity may lead to the development of multiple chronic disease states, including hypertension, dyslipidemia, and type 2 diabetes mellitus. Over a half billion adults worldwide are affected by obesity, and more than two-thirds of adults are either obese or overweight in the United States. Diet and exercise have been the mainstays of treatment in this population; however, once failed, noninvasive, long-term effective treatment modality is lacking, and medications may potentially fill the void. Lorcaserin and phentermine/topiramate were approved by the FDA in June 2012 and July 2012, respectively, as adjuncts to diet and exercise for chronic weight management of obese (body mass index [BMI] ≥ 30 kg/m2) or overweight (BMI ≥ 27 kg/m2) individuals with comorbidities.

OBJECTIVE

To review the phase 3 trials of lorcaserin and phentermine/topiramate and provide managed care considerations that may be taken into account as a result.

METHODS

A MEDLINE review was performed for articles published and available through September 17, 2012, using keywords "lorcaserin" or "phentermine/topiramate" with an emphasis on phase 3 trials. The literature search was limited to randomized controlled trials in humans published in the English language. Additional information on lorcaserin from its FDA review was obtained from the FDA website.

RESULTS

5 pivotal phase 3 trials were identified: 3 for lorcaserin and 2 for phentermine/topiramate. Both agents demonstrated a statistically significant higher proportion of individuals who lost ≥ 5% of body weight, as well as higher mean weight loss when compared with placebo. Safety concerns for lorcaserin include cardiac valvulopathy and increased risk of psychiatric, cognitive, and serotonergic adverse effects. Teratogenicity and increased heart rate are major safety concerns regarding phentermine/topiramate.

CONCLUSIONS

Health care decision makers have many factors to consider when developing strategies to fight obesity. Despite a great need for new therapies to treat obesity, medications used for weight loss have significant side-effect profiles and contraindications that may limit therapy. An appropriate utilization management strategy is needed.

Changes in cardiovascular risk associated with phentermine and topiramate extended-release in participants with comorbidities and a body mass index ≥27 kg/m(2)

The aim of this analysis was to evaluate changes in cardiovascular risk factors in obese patients with dyslipidemia and/or hypertension receiving phentermine (PHEN) and topiramate extended-release (TPM ER). In the 56-week, randomized, double-blind, placebo-controlled, multicenter CONQUER trial, PHEN/TPM ER demonstrated significant weight loss compared with placebo in overweight or obese participants with ≥2 weight-related co-morbidities. Participants with body mass indexes of 27 to 45 kg/m(2) were randomized to placebo, PHEN 7.5 mg/TPM ER 46 mg, or PHEN 15 mg/TPM ER 92 mg; participants also received lifestyle modification counseling. Primary end points were percentage weight loss and the proportion of participants achieving ≥5% weight loss. Additional end points were changes in lipid variables in the dyslipidemia population and blood pressure in the hypertensive population, stratified by treatment and magnitude of weight loss. PHEN/TPM ER produced significantly greater dose-related mean percentage weight loss compared with placebo in the subgroups of participants with dyslipidemia and those with hypertension. Regardless of treatment group assignment, participants with dyslipidemia who lost ≥5% of their baseline weight experienced significantly greater reductions in triglycerides (-14.5% to -39.8%), and in non-high-density lipoprotein cholesterol (-9.4% to -14.8%) than those losing <5% of their weight (p <0.05). Similarly, participants with hypertension at baseline showed reduced systolic blood pressure by -7.5 to -11.8 mm Hg (p <0.001 vs those with <5% weight loss). In conclusion, the dose-related weight loss induced by PHEN/TPM ER treatment was accompanied by significant improvements in cardiovascular disease risk factors in participants who had dyslipidemia or hypertension at baseline, suggesting that facilitating weight loss by augmenting lifestyle changes with pharmacotherapies may decrease the risk for cardiovascular disease in obese and overweight patients with co-morbidities.

Phentermine and topiramate extended-release for the obesity: new kids on the block

Obesity is a major public health concern associated with increased morbidity and mortality. Its prevalence is rising worldwide mainly due to modern lifestyle habits. Several mechanisms like inflammation, endothelial dysfunction, increased sympathetic tone, high leptin and insulin concentrations as well as enhanced thrombogenesis are implicated to the emergence and progress of cardiovascular disease. Although, changes in the lifestyle remain the cornerstone of antiobesity treatment, alone do not always provide the desired weight loss. Often, the addition of pharmacotherapy or bariatric surgery is considered the treating option for patients meeting eligibility criteria. Although, bariatric surgery is limited to patients with a high body mass index due to the risks of the procedures, the effects of anti-obesity medication on cardiovascular outcome are still unclear. Several anti-obesity drugs have been abandoned because of serious adverse events. Qsymia is a combination of phentermine and topiramate used for obesity treatment. Administration of this drug reduces body weight and has favorable effects in various metabolic and anthropometric parameters. However, there are concerns regarding cardiovascular safety of this drug. In this review, we are going to present the history of current antiobesity medication focusing on the combination of phentermine and topiramate and recent patents.

[Phentermine--a "weighty" or a dangerous substance?]

According to international surveys, the appetite suppressant phentermine has frequently been seized although its approval has been withdrawn in Germany. Phentermine is an isomer of methamphetamine though is not optically active such as e. g. amphetamine. The drug acts as a potent substrate at the norepinephrine transporter simultaneously promoting its release; it has a weaker activity at the dopamine transporter whereas its activity towards the serotonin transporter is negligible. Overall, its pharmacological action is comparable to that of amphetamine albeit less strong. Due to its declining effect with time and its addiction potential it has been recommended that phentermine should be used for a few weeks only. Phentermine hydrochloride is a readily soluble salt; absorption of the resinate compound is considerably slower. The drug is not extensively biotransformed; p- and N-hydroxyphentermine are the primary metabolites also being excreted as glucuronide conjugates. Gas chromatographic techniques to identify and to quantify phentermine in biological specimens are applicable following derivatization; however, liquid chromatography coupled to mass spectrometry is currently preferred for analysis of urine, serum or hair. Short-term clinical studies having been performed in the 80s and 90s revealed no serious harmful side effects. However, there are case reports proposing that phentermine usage might be associated with severe health risks due to hypertension, vasoconstriction and vasculopathy; in some individuals, mental illness had been observed. Apart from the legal consequences following purchase of drugs that have been withdrawn its user will simultaneously run serious and unpredictable health risks.

Topiramate + phentermine. An excessively dangerous appetite-suppressant combination

The cornerstones of treatment for obesity, and even more so for simple overweight, are dietary measures and physical exercise. There are no drugs with a favourable harm-benefit balance in this setting. A fixed-dose combination of topiramate, an antiepileptic drug, and phentermine, an appetite-suppressant amphetamine, has been refused marketing authorisation in the European Union, after being licensed in the United States. There are no randomised controlled trials of topiramate + phentermine in the prevention of complications of obesity. In the three available placebo-controlled trials, patients treated with topiramate 46 mg per day + phentermine 7.5 mg per day for between 1 and 2 years lost about 6-8 kg more than patients who received a placebo. About one-quarter of this weight loss was regained within a year after treatment discontinuation. The known adverse effects of the two drugs composing this combination are additive, and include psychiatric disorders, cardiac arrhythmias and metabolic acidosis. The risk of serious cardiovascular disorders was not adequately studied during clinical trials. Many women of child-bearing age would be exposed to this combination, which can provoke fetal abnormalities, including cleft palate, if taken during pregnancy. In practice, the topiramate + phentermine combination has an unfavourable harm-benefit balance and has no place in the treatment of obesity.

Phentermine: an appetite-suppressant amphetamine classified as a narcotic in France. Is a combination with topiramate on the horizon?

In France, extra restrictions have been placed on this appetite-suppressant drug. Phentermine is widely used in many countries despite its multiple adverse effects and lack of proven efficacy in preventing complications of obesity.

Two-year sustained weight loss and metabolic benefits with controlled-release phentermine/topiramate in obese and overweight adults (SEQUEL): a randomized, placebo-controlled, phase 3 extension study

BACKGROUND

Obesity is a serious chronic disease. Controlled-release phentermine/topiramate (PHEN/TPM CR), as an adjunct to lifestyle modification, has previously shown significant weight loss compared with placebo in a 56-wk study in overweight and obese subjects with ≥2 weight-related comorbidities.

OBJECTIVE

This study evaluated the long-term efficacy and safety of PHEN/TPM CR in overweight and obese subjects with cardiometabolic disease.

DESIGN

This was a placebo-controlled, double-blind, 52-wk extension study; volunteers at selected sites continued with original randomly assigned treatment [placebo, 7.5 mg phentermine/46 mg controlled-release topiramate (7.5/46), or 15 mg phentermine/92 mg controlled-release topiramate (15/92)] to complete a total of 108 wk. All subjects participated in a lifestyle-modification program.

RESULTS

Of 866 eligible subjects, 676 (78%) elected to continue in the extension. Overall, 84.0% of subjects completed the study, with similar completion rates between treatment groups. At week 108, PHEN/TPM CR was associated with significant, sustained weight loss (intent-to-treat with last observation carried forward; P < 0.0001 compared with placebo); least-squares mean percentage changes from baseline in body weight were -1.8%, -9.3%, and -10.5% for placebo, 7.5/46, and 15/92, respectively. Significantly more PHEN/TPM CR-treated subjects at each dose achieved ≥5%, ≥10%, ≥15%, and ≥20% weight loss compared with placebo (P < 0.001). PHEN/TPM CR improved cardiovascular and metabolic variables and decreased rates of incident diabetes in comparison with placebo. PHEN/TPM CR was well tolerated over 108 wk, with reduced rates of adverse events occurring between weeks 56 and 108 compared with rates between weeks 0 and 56.

CONCLUSION

PHEN/TPM CR in conjunction with lifestyle modification may provide a well-tolerated and effective option for the sustained treatment of obesity complicated by cardiometabolic disease. This trial was registered at clinicaltrials.gov as NCT00796367.

Appetite suppressants in pregnancy

OBJECTIVES

Both, obesity as well as anorexia may be associated with infertility and other complications of pregnancy. Weight loss during pregnancy is therefore considered a risk factor. Weight loss and appetite suppressant are contraindicated during pregnancy, but the unintended exposure is probably not associated with higher risk. Our work was focused on trends in the appetite suppressants use in the Czech Republic and their embryotoxicity.

METHODS

The pregnancies exposed to various appetite suppressants were followed prospectively in the years 1997-2012. The study group was compared to the comparison group which enrolled pregnant women exposed to non-teratogenic drugs. Drugs used as appetite suppressants were sibutramine and phentermine.

RESULTS

Number of calls for this type of exposure was rare till 2005. Their number started to increase until 2009. Later, number of calls decreased because both drugs were withdrawn from the market. This finding reflects increasing tendency for the weight control in the group of fertile women in the Czech Republic. In our study, we did not reveal differences in pregnancy outcomes between study and comparison groups.

CONCLUSIONS

However, we should be aware of the increasing food supplements exposure, that could be used as alternative to the appetite suppressants. Their potential risk results from the limited or completely absent control of their origin. Some of them have probably only placebo effect, but some of them could represent the risk.

Valvular heart disease with the use of fenfluramine-phentermine

Exposure to the anorectic drug fenfluramine, alone or in combination with phentermine, a noradrenergic central nervous system stimulant, has been associated with unusual cardiac valvular morphology and resultant regurgitation of the left- and right-sided heart valves. The prevalence of significant valvular disease associated with the use of these anorectic drugs is reported to be as high as 23%. Herein, we report the occurrence of multivalvular disease and pulmonary hypertension associated with fenfluramine-phentermine use, discovered in an obese 59-year-old woman before expected gastric bypass surgery.

Cardiac arrest in the setting of diet pill consumption

The obesity epidemic currently plaguing the United States has spurred the development of a vast number of drugs to assist in the battle against obesity and its associated complications. The need to loose weight often causes patients to loose sight of or even ignore the serious side effects of some of the most widely used weight-loss medications. Here we present the case of ventricular tachycardia/fibrillation arrest in an otherwise healthy 48-year-old woman who was taking no medications other than phentermine, a common appetite suppressant that functions as a central nervous system stimulant through activation of the noradrenergic pathway of the sympathetic nervous system.

The longitudinal effects of fenfluramine-phentermine use

The use of previous anorectic medications and the combined use of the anorectic medications fenfluramine and phentermine (Fen-Phen) have been associated with varying degrees of valvular regurgitation and pulmonary hypertension. More recent reports have suggested a lower incidence of both than was previously reported. Comparisons of patients with similar body mass index (BMI) have been missing as well as information regarding chamber dimensions and pressures. Using transthoracic 2D, M-mode, and Doppler echocardiography, 57 men and women (30 Fen-Phen and 27 BMI-matched individuals/BMIMCG) were studied to determine their chamber dimensions, wall motion, diastolic function, valvular abnormalities, left ventricular ejection fractions (LVEFs), and pulmonary artery pressures (pAPs). The 30 Fen-Phen subjects were studied shortly after discontinuing the medications and again 6 to 12 months later. The results in these subjects were then compared with the valvular findings of 660 randomly selected cardiac patients with non-Fen-Phen-induced heart disease (NFPHD). Valvular regurgitation was greatest among patients who had recently discontinued the use of Fen-Phen (EFP) with 57% of all valves having regurgitation, 87.5% of which were "mild." These same individuals also had the largest left ventricles at end (LVEDD) diastole (5.03 +/-0.22 cm) and systole (LVESD). The LVESDs were statistically larger (p <or= 0.05) than that seen in the other groups, while at the same time their LVEFs were statistically (p <or= 0.01) lower (53.44 +/-9.48%). These same patients had statistically (p <or= 0.05) greater PAPs (29.21 +/-10.52 mm Hg), which were associated with a lower incidence rate (14%) of pulmonic regurgitation (PR). The number of people with aortic regurgitation (AR), statistically (p <or= 0.05) decreased (40%) as the duration of time since discontinuing Fen-Phen increased (late Fen-Phen/LFP). However, for those individuals who continued to have AR, there was an increase in the number of people who progressed from mild to moderate AR, with an associated increase in LVEDD (5.41 +/-0.55 cm), LVESD (3.51 +/- 0.84 cm), and LVEF (63.45 +/-15.25%). The LFP studies showed a statistical (p <or= 0.001) increase in PR with a subsequent drop in PAPs from 29.21 +/-10.52 mm Hg in the early (EFP) studies to 14.02 +/-1.35 mm Hg, which was augmented with weight-bearing and Valsalva maneuvers. The reduction in the percentage of individuals with valvular regurgitation and pulmonary hypertension appears to be due to changes in the heart valves, pressures, and chamber size. The incidence of tricuspid and mitral regurgitation decreased with time, while pulmonic and aortic regurgitation tended to increase or become more severe when present. Dilatation of the pulmonary ring, resulting from elevated pulmonic pressures with subsequent pulmonary regurgitation and reduction in pulmonary artery pressures, appears to be a functional change in the hearts of these individuals with unknown long-term consequences.