Weight loss medication prescription prevalence in the active component, 2018-2023

The U.S. military has witnessed rising obesity among active component service members. The Department of Defense authorized coverage of weight loss medications in 2018, but no study has evaluated prescription prevalence within the active component. This descriptive retrospective cohort study analyzed data from active component U.S. military service members from January 2018 through June 2023. The study used data from the Defense Medical Surveillance System to determine prescription period prevalence of weight loss medication. Data on demographics, body mass index, and history of diabetes were considered. The study revealed a 100-fold increase in the prescription period prevalence of weight loss agents in the active component from their initial authorization date. Demographics associated with higher prescription period prevalence were non-Hispanic Black race and ethnicity, female sex, and older age. Service members in the health care occupations and the Navy had higher prevalence compared to other service branches and occupations. The findings indicate a significant rise in the period prevalence of weight loss prescriptions over time. Further research is recommended to assess the effectiveness, safety, and use in austere military environments.

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.

Effects of Pharmacotherapy for the Treatment of Obesity in an Urban, Safety-Net Population

OBJECTIVE

To evaluate the effect of common weight loss pharmacotherapies among low-income, racially diverse adult patients at an urban safety-net weight management clinic.

METHODS

Our retrospective review from 2015 to 2019 examined patients who took either GLP-1 analog (GL) or phentermine/topiramate (PT) for ≥90 days and patients who exclusively pursued non-pharmacologic treatment for comparison. Changes in weight, blood pressure, and hemoglobin A1c at 1-year follow-up were reported.

RESULTS

We analyzed 22 GL and 26 PT patients and included 40 patients who pursued only lifestyle modifications (LM). All three groups achieved significant weight loss at one year: GL -3.69 (interquartile range (IQR): -11.0, -1.77) kg (p=0.0004), PT -7.01 (IQR: -13.4, -1.45) kg (p<0.001), and LM -3.01 (IQR: -6.81, 1.13) kg (p=0.005). There was no significant difference in the median weight loss (p=0.11) between the three groups. We observed no significant changes in systolic blood pressure but saw a significant change of -0.75 in hemoglobin A1c (IQR: -1.35, -0.25) (p=0.01) among patients with diabetes in the GL group.

CONCLUSIONS

Our real-world applications of GLP-1 and phentermine/topiramate suggest that both are effective weight loss medication regimens in low-socioeconomic status patients.

A Narrative Review: Phentermine and Topiramate for the Treatment of Pediatric Obesity

The prevalence of pediatric obesity has increased exponentially over the past four decades. The American Academy of Pediatrics recently released updated clinical practice guidelines highlighting the importance of identifying pediatric obesity as a chronic disease. The guidelines support consideration of concurrent treatment with intensive lifestyle interventions, obesity pharmacotherapy, and bariatric surgery. The dramatic rise in pediatric obesity has spurred interest in utilizing obesity pharmacotherapy to support sustained weight reduction in pediatric cohorts, in the hopes of preventing the emergence of later-appearing, significant co-morbidities. Despite the enormous demand, the obstacles posed by performance of needed clinical trials in the pediatric population markedly limits available pharmacotherapy for the treatment of obesity in pediatrics. Currently, there are five medications approved by the Food and Drug Administration for use in youth with obesity. In 2022, the phentermine/topiramate (PHEN/TPM), once-daily, controlled-release, combination product received FDA approval, for the indication of chronic weight management, in youth with obesity, ages 12 years and older. The objectives of this narrative review are to: (1) Review the mechanism of action of phentermine and topiramate, (2) Summarize the safety and efficacy data of topiramate and phentermine use as both monotherapies and in combination, and (3) Discuss clinical practice guidelines and clinical implications, for the use of these agents in youths with obesity.

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.

Lorcaserin and phentermine exert anti-obesity effects with modulation of the gut microbiota

Although drugs have been reported to modulate the gut microbiota, the effects of anti-obesity drugs on the gut microbiota remain unclear. Lorcaserin (LS) and phentermine (PT) are commonly used anti-obesity drugs. However, to our best knowledge, no studies have simultaneously assessed the effects of LS and PT on obesity and gut microbiota. This study aimed to explore the relationship between the anti-obesity effects of LS and PT and re-modulation of host gut microbiota. To test hypothesis, we fed C57BL/6J mice with a high-fat diet supplemented with LS and PT via oral gavage for 8 weeks. After sacrifice, body weight, fat accumulation, and serum biomarkers were measured, and the gut microbial composition was analyzed using 16 s rRNA amplicon sequencing. LS and PT were observed to modulate the gut microbial composition and restore gut microbial dysbiosis, as indicated by an increased Firmicutes/Bacteroidetes ratio. Significantly modulated genera by LS and PT treatment were strongly correlated with obesity-related markers. Additionally, LS and PT increased the mRNA level of G protein-coupled receptor 120 (GPR120) in the colon tissue. ASV3566, which corresponds to Eubacterium coprostanoligenes, was correlated with GPR120 and obesity-related markers such as glutamic pyruvic transaminase (GPT) and serum triglyceride (TG). In conclusion, LS and PT can modulate the gut microbiota dysbiosis and the gut microbiota plays a role in mediating the anti-obesity effect of drugs.

Positive Regadenoson Stress Test in a Patient on Phentermine With Normal Coronaries

Obesity is a well-established cardiovascular (CV) risk factor with greater mortality and morbidity rates than the general population. Phentermine is a weight loss medication that is approved for short-term obesity treatment in conjunction with lifestyle modifications to decrease CV risk. A 51-year-old female with Raynaud's phenomenon who was started on phentermine one week prior presented with a one-day history of palpitations. Subsequent workup revealed non-ST elevation myocardial infarction (NSTEMI) on presentation and worsening ST segment depressions following regadenoson injection during pharmacological stress testing. Although current evidence suggests that the use of phentermine is safe and may even reduce the risk of CV disease in obese patients, it still may pose adverse CV effects. A detailed medical history, including medications used and predisposing conditions, is crucial to help identify and possibly prevent exacerbation of such CV side effects.

Weight Loss at First Month and Development of Tolerance as Possible Predictors of 30 mg Phentermine Efficacy at 6 Months

The efficacy of anti-obesity drugs usually does not consider the high degree of interindividual variability in responses to the drug which could affect the decision to withdraw the drug early due to ineffectiveness or to continue therapy according to specific expectations of success. The aim of this study was to analyze body weight loss in kilograms during the first month (1 mo-BWL_kg) of treatment with 30 mg phentermine and development of tolerance to phentermine, on its 6-month efficacy. One hundred sixty-six subjects with obesity were individually or jointly analyzed in the study. Subjects with 1 mo-BWL_kg of <1 kg, 1–3 kg, 3–5 kg, and ≥5 kg reached 6-month mean percentage body weight reductions (BWR%) of approximately 3%, 5%, 10%, and 15%, respectively. Development of late tolerance (4–6 months) to phentermine had a lower impact than early tolerance (2–3 months). Subjects with 1 mo-BWL_kg < 3 kg who developed early tolerance did not achieve relevant BWR% (≥5%) at month 6, while the rest of the subgroups achieved increasing and progressive BWR%, according to their 1 mo-BWL_kg range and time of onset of tolerance. The 1 mo-BWL_kg and development of tolerance to phentermine could be useful to predict the expected 6-month efficacy trends in obese patients treated with 30 mg phentermine.

ST-Elevation Myocardial Infarction in a 23-Year-Old Female: The Mystery of Thrombus Formation

Acute ST-elevation myocardial infarction (STEMI) is rarely seen in young adults, however, when encountered, the underlying cause is either a genetic condition leading to early-onset coronary artery disease (CAD), an acquired pro-thrombotic condition, or an idiopathic condition like spontaneous coronary artery dissection (SCAD). Our case describes a healthy 23-year-old female who presented with sudden onset severe angina and was found to have a laminated thrombus in the left anterior descending coronary artery (LAD), with no evidence of intraluminal dissection or plaque rupture. Although the underlying etiology of thrombus formation remains unknown, coronavirus disease 2019 (COVID-19) related thrombotic event is the prime suspect. In addition, another culprit that cannot be excluded is phentermine-induced coronary vasospasm, a commercially available medication for weight loss. This report addresses current literature on acute coronary syndromes in young adults and reviews the potential etiologies for coronary artery thrombosis, which led to a near-fatal acute coronary syndrome in our patient.

Supraventricular tachycardia with the use of phentermine: case report and review of literature

Case: A 34-year-old woman with no significant past medical history presented to the hospital with sudden onset of palpitations with associated dyspnea and chest discomfort. She denied any similar previous episodes. Initial electrocardiogram (EKG) was consistent with a short R-P interval supraventricular tachycardia (SVT). Her transthoracic echocardiogram (TTE) revealed no structural abnormalities, TSH levels were normal, and urine drug screen was negative for any recreational drugs. However, the patient had been taking phentermine for weight loss.Discussion: The exact mechanism is not clear; however, we postulate that the sympathomimetic effects of phentermine likely contribute to SVT induction through enhanced AV nodal conduction or increased atrial ectopy. Conclusions: The only medication she was taking at home was phentermine, and the palpitations did not recur after discontinuation of the drug during follow-up. It is important to collect a thorough medication history when patients present with AV nodal reentrant tachycardia (AVNRT) or other SVT.

Effects of Orlistat/Phentermine versus Phentermine on Vascular Endothelial Cell Function in Obese and Overweight Adults: A Randomized, Double-Blinded, Placebo-Controlled Trial

BACKGROUND

In clinical practice, concomitant treatment of orlistat with phentermine is commonly used off-label. However, clinical trials have not been performed to evaluate whether their combination improves metabolic parameters and cardiovascular risk factors other than weight loss. Therefore, we aimed to compare the efficacy of concomitant administration of orlistat and phentermine versus phentermine alone on the endothelial cell function in overweight and obese adults with back pain.

METHODS

We conducted a 12-week, double-blinded, placebo-controlled clinical trial involving 114 patients with a body mass index of ≥30 (obese) or ≥27 (overweight) with weight-related comorbidities. We randomly assigned patients in a 1:1 ratio to receive orlistat (120mg) three times daily and phentermine (37.5mg) once daily, or a placebo three times daily and phentermine (37.5mg) once daily. Primary endpoint was changes in endothelium-dependent vasodilatation measured using ultrasound assessment of flow-mediated dilatation (FMD). Differences within groups after intervention were compared using the paired t-test or Wilcoxon signed-rank test. Differences in changes between the groups were calculated using an analysis of covariance after adjusting for each baseline value.

RESULTS

Mean weight loss during the 12-week study period was 6.1kg in the orlistat/phentermine group and in the placebo/phentermine group. Adjusted mean changes in total and non-high-density lipoprotein cholesterol were significantly greater in the orlistat/phentermine group than in the placebo/phentermine group. Adjusted mean changes in endothelium-dependent FMD were significantly greater in the orlistat/phentermine group than in the placebo/phentermine group (4.97±0.98% vs 2.05±0.99%, respectively; p=0.038). Changes in endothelium-independent nitroglycerin-mediated dilatation were not significantly different between the groups.

CONCLUSION

Orlistat/phentermine significantly improved the vascular endothelial cell function compared with phentermine alone. Orlistat might have beneficial effects on the decrease of the risk of cardiovascular disease, especially in overweight and obese patients with comorbidities.

TRIAL REGISTRATION

ClinicalTrails.gov number, NCT03675191.

The limits and challenges of antiobesity pharmacotherapy

INTRODUCTION

Pharmacotherapy is a useful adjunct when patients with obesity are unable to achieve adequate benefit from lifestyle interventions.

AREAS COVERED

This review covers the history of antiobesity drugs, efficacy, and risks of currently approved drugs, limits of their usefulness in clinical practice, gaps in knowledge, methodological limitations of clinical trials, and reasons for underutilization.

EXPERT OPINION

In randomized controlled trials, currently approved antiobesity drugs have yielded an average weight loss ranging from approximately 3% to 9% relative to placebo at 1 year. Inadequate inclusion of racial and ethnic minorities and men, and high dropout rates in clinical trials limit generalizability of these findings to clinical practice. Weight loss achieved with antiobesity drugs is generally associated with lowered glycemia, but improvements in blood pressure and lipid measures tend to be marginal. There is limited evidence for sustained weight loss beyond 1 year and for safety and efficacy of antiobesity drugs in children and adolescents, and in post-bariatric surgery patients. None have demonstrated reduction in major adverse cardiovascular events or other significant disease outcomes. Limited health insurance coverage and negative perceptions of physicians have hindered the utilization of antiobesity drugs.

A randomized, placebo-controlled crossover trial of phentermine-topiramate ER in patients with binge-eating disorder and bulimia nervosa

OBJECTIVE

Open trials suggest phentermine/topiramate ER (PHEN/TPM-ER), food and drug administration (FDA) approved for obesity, has utility for binge eating. With no randomized controlled trials (RCTs) yet performed, this trial aimed to evaluate PHEN/TPM-ERs efficacy and safety in a crossover RCT for patients with binge-eating disorder (BED) or bulimia nervosa (BN).

METHOD

Participants were randomized to 12-weeks PHEN/TPM-ER (3.75 mg/23 mg-15 mg/92 mg) or placebo followed by 2-weeks drug washout, then 12-week crossover. Demographics, vitals, eating disorder behaviors, mood, and side effects were measured. Primary outcome was objective binge-eating (OBE) days/4-weeks; secondary outcomes included binge abstinence. Mixed-effect models estimated treatment effects, with fixed effects adjusting for treatment, study period, and diagnosis.

RESULTS

The 22 adults (BED = 18, BN = 4) were female (96%), Caucasian (55%), aged 42.9 (SD = 10.1) years with body mass index = 31.1 (SD = 6.2) kg/m2 . Baseline OBE days/4-weeks decreased from 16.2 (SD = 7.8) to 4.2 (SD = 8.4) after PHEN/TPM-ER versus 13.2 (SD = 9.1) after placebo (p < .0001), with abstinence rates = 63.6% on PHEN/TPM-ER versus 9.1% on placebo (p < .0001). Weight changes = -5.8 kg on PHEN/ TPM-ER versus +0.4 kg on placebo. Drop-out = 2 (9%) on PHEN/TPM-ER and 2 (9%) on placebo, with few side effects. Vital sign changes with PHEN/TPM-ER were minimal and similar to placebo. Responses were not significantly different for BED versus BN.

DISCUSSION

This first RCT to evaluate the efficacy and safety of PHEN/TPM-ER for BED/BN found this drug combination significantly more effective at reducing binge eating than placebo and well tolerated. However, with only four participants with BN, findings regarding the safety of PHEN/TPM-ER in patients with BN must be taken with caution.

TRIAL REGISTRATION

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

Is There a Prescription to Treat Pediatric Obesity?

Pediatric obesity is complex-in every way. The pathogenesis, which is a result of a multitude of factors combined with social and environmental factors makes it a crisis with overwhelming challenges. It is difficult to treat pediatric obesity; however, guidelines attempt to clarify how to approach treatment. These strategies are mostly interventions in lifestyle because only 1 medication is approved for treating obesity in children. The approach to the treatment of pediatric obesity will need to be a one that relies on the available data, a continued drive for additional research and publication, sharing of practice experience, and continued efforts at prevention.

Antiobesity Medication Use in 2.2 Million Adults Across Eight Large Health Care Organizations: 2009-2015

OBJECTIVE

The aim of this study was to examine the prescribing patterns and use of antiobesity medications in a large cohort of patients using data from electronic health records.

METHODS

Pharmacy- and patient-level electronic health record data were obtained on 2,248,407 adults eligible for weight-loss medications from eight geographically dispersed health care organizations.

RESULTS

A total of 29,964 patients (1.3% of total cohort) filled at least one weight-loss medication prescription. This cohort was 82.3% female, with median age 44.9 years and median BMI 37.2 kg/m² . Phentermine accounted for 76.6% of all prescriptions, with 51.7% of prescriptions being filled for ≥ 120 days and 33.8% filled for ≥ 360 days. There was an increase of 32.9% in medication days for all medications in 2015 compared with 2009. Higher prescription rates were observed in women, black patients, and patients in higher BMI classes. Of 3,919 providers who wrote at least one filled prescription, 23.8% (n = 863) were "frequent prescribers" who wrote 89.6% of all filled prescriptions.

CONCLUSIONS

Weight-loss medications are rarely prescribed to eligible patients. Phentermine accounted for > 75% of all medication days, with a majority of patients filling it for more than 4 months. Less than one-quarter of prescribing providers accounted for approximately 90% of all prescriptions.

Phentermine Use During First and Second Trimesters Associated with Fetal Stroke

Phentermine is a sympathomimetic amine used for the short-term weight loss that has been associated with ischemic and hemorrhagic strokes in adults. The effects of this medication on a developing fetus are not well studied. We present the case of a woman who was taking phentermine during the first two trimesters of pregnancy and subsequently delivered a child with bilateral porencephalic cysts likely due to a prenatal stroke.

The Triple Combination Phentermine Plus 5-HTP/Carbidopa Leads to Greater Weight Loss, With Fewer Psychomotor Side Effects Than Each Drug Alone

Obesity has become a serious public health problem. Although diet, surgery, and exercise are the primary treatments for obesity, these activities are often supplemented using appetite suppressants. A previous study reported that obesity specialists frequently prescribed a new drug combination for its treatment that includes phentermine (Phen; dopaminergic appetite suppressant), a serotonin (5-HT) precursor 5-hydroxytryptophan (5-HTP; an appetite suppressant that increases the 5-HT concentration), and carbidopa (CB; peripheral blocker of conversion of 5-HTP to 5-HT). Despite its widespread use, there is neither a preclinical study confirming the drug efficacy nor studies of its effects on the brain. To fill this gap, in rats for seven consecutive days, we administered Phen intraperitoneally at different doses either alone or in combination with a fixed dose of 5-HTP/CB. In a different group, we infused drugs via an intraperitoneal catheter while extracellular-recordings were performed in the nucleus accumbens shell (NAcSh), a brain region with dopamine-releasing effects that is involved in the action of appetite suppressants. We found that the triple-drug combination leads to greater weight-loss than each drug alone. Moreover, and as the treatment progresses, the triple drug combination partially reversed psychomotor side-effects induced by Phen. Electrophysiological results revealed that Phen alone evoked a net inhibitory imbalance in NAcSh population activity that correlated with the onset of psychomotor effects. In addition, and unlike the greater weight loss, the addition of 5-HTP/CB did not alter the Phen-evoked inhibitory imbalance in NAcSh responses. Subsequent experiments shed light on the underlying mechanism. That is the majority of NAcSh neurons modulated by 5-HTP/CB were suppressed by Phen. Notably, and despite acting via a different mechanism of action (DA for Phen vs. 5-HT for 5-HTP/CB), both drugs recruited largely overlapping NAcSh neuronal ensembles. These data suggest that the neural correlates of the greater weight loss could be located outside the NAcSh, in other brain circuits. Furthermore, we conclude that Phen + 5-HTP/CB is a potential treatment for overweight and obesity.

Pharmacotherapy of obesity - state of the art

Obesity, which affects about 13% of the world population, results in significant deterioration of health and serious clinical, mainly meta-bolic and cardiovascular complications. Although the basis of therapeutic treatment is behavioural treatment, often non-pharmacological effects do not produce the desired effect. Currently there are several drugs with a safe action profile that improve the effect of treatment (5-10% weight reduction). The aim of the paper is to present the potential of modern pharmacotherapy in the treatment of obesity, in terms of mechanism of action, efficacy, and side effects, in order to individualise therapy. The drugs already registered include substances with a variety of mechanisms of action, including phentermine, orlistat, lorcaserin, and liraglutide. Compounded preparations (phenter-mine/topiramate, naltrexone SR/bupropion SR) are also available, which, by using low doses of active substances, have beneficial effects while reducing side effects. In addition, several drugs used to treat diabetes, such as metformin, SGLT2 inhibitors, GLP-1 agonists, and pramlintide, promote weight loss, although their use is reserved for diabetics, especially type 2 patients. Regarding the current alarm-ing epidemiological data there is a need for intensive prevention and treatment of obesity as well as the development of a new form of pharmacotherapy (new substances and treatment regimens) to develop effective, safe, and, above all, long-term effective therapy for the treatment of obesity.

Effect of Lorcaserin Alone and in Combination with Phentermine on Food Cravings After 12-Week Treatment: A Randomized Substudy

OBJECTIVE

This study evaluated the effect of lorcaserin 10 mg twice daily (LOR BID), or with phentermine 15 mg once daily (LOR BID + PHEN QD) and 15 mg twice daily (LOR BID + PHEN BID), in conjunction with energy restriction on food cravings.

METHODS

Two hundred and thirty-five patients without diabetes but with obesity or overweight and ≥ 1 comorbidity received LOR BID, LOR BID + PHEN QD, or LOR BID + PHEN BID for 12 weeks in a randomized double-blind study. The Food Craving Inventory (FCI) and the Control of Eating Questionnaire (COEQ) were administered over 12 weeks.

RESULTS

The FCI total score and the subscale scores reduced from baseline in all groups. The least squares means (95% confidence intervals) for the total scores were -0.65 (-0.75 to -0.55), -0.75 (-0.84 to -0.65), and -0.84 (-0.95 to -0.74) in the LOR BID, LOR BID + PHEN QD, and LOR BID + PHEN BID groups, respectively. Cravings assessed by COEQ reduced from baseline in all groups. In general, the combination treatments were more effective than lorcaserin alone. At week 12, except for fruit juice and dairy products, general and specific cravings reduced in LOR BID + PHEN BID compared with LOR BID (P < 0.05).

CONCLUSIONS

Lorcaserin in combination with phentermine improves control of food cravings during short-term energy restriction.

5-alpha-dihydrotestosterone elevations associated with phentermine use

BACKGROUND

A case of 5-alpha-dihydrotestosterone (DHT) elevation associated with phentermine initiation is reported, and possible mechanisms are discussed. There are no published reports of this association in the literature.

METHODS

Clinical and laboratory information is described.

RESULTS

A 72-year-old male with metastatic prostate cancer taking dutasteride to lower his DHT levels initiated phentermine 15 mg daily for weight loss. His DHT level drawn within 1 week prior to starting phentermine was 9.9 pg/ml. When reporting for follow up 2 weeks later, his DHT level had increased to 114 pg/ml. The DHT level was checked again 2 weeks after that visit, and had increased to 174 pg/ml. At that time, phentermine was discontinued, and 1 week later, the DHT level had decreased to 20.1 pg/ml. Over the next 4 months, the patient's DHT levels were maintained at less than 20 pg/ml. Phentermine 15 mg daily was then reinitiated while his DHT level was 7.5 pg/ml. Two weeks after resuming phentermine, his DHT level had again increased to 196 pg/ml. The patient's phentermine was then discontinued, and around 1 week later, his DHT level had fallen to 5.1 pg/ml.

CONCLUSION

A 72-year-old male with metastatic prostate cancer experienced profound increases in DHT upon initiation of phentermine despite continuation of his baseline dutasteride therapy. The etiology of these increases is still unclear.

The Potential Role of Combination Pharmacotherapy to Improve Outcomes of Pediatric Obesity: A Case Report and Discussion

There is a gap in treatment modalities for pediatric patients with obesity for whom lifestyle modification therapy, on the one hand, may be insufficient to meaningfully reduce BMI, and bariatric surgery, which on the other hand, may not be indicated, available or desired. Although pharmacotherapy may help fill this treatment void, there is a paucity of FDA-approved medications indicated for pediatric obesity and further, most are single agents with only modest mean treatment effects. In contrast, combination pharmacotherapy, such as phentermine/topiramate, appears to offer greater weight loss efficacy in adults and may prove to be superior to monotherapy for pediatric patients as well. This case report describes the clinical management of severe obesity in a 10 year old girl with lifestyle modification therapy and subsequent addition of first topiramate and later phentermine. Using the case as a platform, the current state of pharmacotherapy for pediatric obesity will be described thereby highlighting the limited efficacy of single agents. Additionally, the biological rationale for combination pharmacotherapy, including potential mechanisms which may account for the poor response to single agents, will be discussed.

Psychoactive substances belonging to the amphetamine class potently activate brain carbonic anhydrase isoforms VA, VB, VII, and XII

Identifying possible new biological activities of psychoactive substances belonging to various chemical classes may lead to a better understanding of their mode of action and side effects. We report here that amines structurally related to amphetamine, a widely used psychoactive substance, such as amphetamine, methamphetamine, phentermine, mephentermine, and chlorphenteramine, potently activate several carbonic anhydrase (CA, EC 4.2.1.1) isoforms involved in important physiological functions. Of the 11 investigated human (h) isoforms, the widespread hCA I and II, the secreted hCA VI, as well as the cytosolic hCA XIII, and membrane-bound hCA IX and XIV were poorly activated by these amines, whereas the extracellular hCA IV, the mitochondrial enzymes hCA VA/VB, the cytosolic hCA VII, and the transmembrane isoform hCA XII were potently activated. Some of these enzymes are abundant in the brain, raising the possibility that some of the cognitive effects of such psychoactive substances might be related to their activation of these enzymes.

Combination therapy for obesity

Obesity is a chronic disease with serious consequences and although lifestyle modification is considered first line treatment, it is often ineffective, especially in the long term. Relatively few people with obesity will undergo the most effective currently available treatment of bariatric surgery. Pharmacotherapy can bridge the gap between lifestyle modification and surgery, but many monotherapies have only modest efficacy or require high doses with unacceptable side effects. As with many other areas of medicine, combination therapy is now becoming accepted as a way of optimising efficacy for weight management, whilst minimising adverse effects. Combinations may use different medications with complementary modes of action. Currently available combination therapies are low-dose phentermine and sustained release topiramate and naltrexone/bupropion. Many other possibilities exist and promising options include combination of phentermine with a sodium glucose co-transporter 2 inhibitor or combination of a glucagon-like peptide 1 agonist with other gut hormones or with a sodium glucose co-transporter 2 inhibitor. The ultimate aim is to match the efficacy of bariatric surgery with a combination of medicines, but this remains an elusive goal.

Off-label drugs for weight management

The global pandemic of obesity and overweight now affects between 2.8 and 3.5 billion of the world population and shows no signs of abatement. Treatment for what is now recognized as a chronic disease includes pharmacotherapy, considered an essential component of comprehensive therapy. New drug discovery is robust, but the pace of the US Food and Drug Administration approval for obesity drugs has been glacial, and only a handful of approved drugs are available for treating obesity. In the last 20 years, the US Food and Drug Administration has approved 208 drugs for cancer, 118 for cardiovascular diseases, 168 for neurological diseases, and 223 endocrinologic drugs, but only 6 for obesity, 2 of which have been taken off market. Currently, there are only 9 drugs approved by the FDA for obesity treatment. US physicians have turned to off-label drug use in their effort to care for increasing numbers of patients with excess adiposity. Phentermine is the most commonly used drug for treating obesity. Although approved only for short-term use, US physicians have used it successfully for long-term since its initial approval in 1959. This drug, used off-label for long-term, has proven to be safe and effective, far safer than the disease it is used to treat. Phentermine and diethylpropion, an equally safe but somewhat less effective drug, are both generic and therefore inexpensive. These drugs have been maligned inappropriately because their two-dimensional structure diagrams resemble amphetamine and also because of unproven presumptions about their potential adverse effects. In the face of an increasing epidemic, worldwide obese and overweight patients deserve effective treatment that prescribing these drugs could provide, if rehabilitated and used more frequently. US physicians will likely continue to use any drug proven useful off-label for this illness until such time as more effective drugs are approved.

Vasospastic myocardial infarction caused by a slimming agent-do not forget non-prescription drugs

A 41-year-old woman presented with central chest discomfort. She had been previously well, was an ex-smoker and reported no regular medication. The ECG developed T-wave changes inferiorly and anterolaterally and troponin I concentrations were elevated confirming non-ST elevation myocardial infarction. Cardiac catheterization showed severe spasm of the right and left anterior descending coronary arteries which resolved with intracoronary nitrates. She later volunteered that prior to presentation she had been taking non-prescription Acti-Phen a slimming agent containing phentermine. Acti-Phen had its licence withdrawn in 2001 because of cardiovascular side effects including coronary spasm. Accordingly, she was advised to avoid Acti-Phen in future. The case emphasizes the importance of obtaining a complete drug history, including non-prescription drugs, in patients presenting with acute coronary syndromes.

Stimulants for the Control of Hedonic Appetite

The focus of this paper is treatment of obesity in relation to the management of hedonic appetite. Obesity is a complex condition which may be potentiated by excessive reward seeking in combination with executive functioning deficits that impair cognitive control of behavior. Stimulant medications address both reward deficiency and enhance motivation, as well as suppressing appetite. They have long been recognized to be effective for treating obesity. However, stimulants can be abused for their euphoric effect. They induce euphoria via the same neural pathway that underlies their therapeutic effect in obesity. For this reason they have generally not been endorsed for use in obesity. Among the stimulants, only phentermine (either alone or in combination with topiramate) and bupropion (which has stimulant-like properties and is used in combination with naltrexone), are approved by the United States Food and Drug Administration (FDA) for obesity, although dexamphetamine and methylpenidate are approved and widely used for treating attention deficit hyperactivity disorder (ADHD) in adults and children. Experience gained over many years in the treatment of ADHD demonstrates that with careful dose titration, stimulants can be used safely. In obesity, improvement in mood and executive functioning could assist with the lifestyle changes necessary for weight control, acting synergistically with appetite suppression. The obesity crisis has reached the stage that strong consideration should be given to adequate utilization of this effective and inexpensive class of drug.

Effectiveness, tolerability and practical application of the newer generation anti-obesity medications

OBJECTIVE

Comparison of the efficacy and tolerability of five newer anti-obesity medications to guide clinical decision making, examining bupropion-naltrexone combination, liraglutide, lorcaserin, orlistat, and phentermine-topiramate combination.

METHODS

A brief literature review and internet search for high-powered, randomized and placebo-controlled drug trials was conducted. Drug trial information was established for five currently approved anti-obesity medications. Secondarily, a statistical comparison of medications through Number Needed to Treat (NNT) and Number Needed to Harm (NNH) analyses were attempted as a way to provide a clinical analysis across these varied medications. Finally, a commentary about clinical application is issued for each agent accounting for typical side-effects, serious side-effects, mechanism of action and ease of use.

RESULTS

All five agents are currently approved oral medications to lower weight. The NNT range was 3-12, and NNH range was 4-17. The agent with the best NNT is phentermine-topiramate combination (NNT=3) and the agent with the best NNH is bupropion-naltrexone combination (NNH=17).

CONCLUSION

When considering each patient's clinical presentation, knowledge of each drug's mechanism of action, side-effect profile, efficacy, and NNT and NNH values can help in selecting an anti-obesity medication to augment his or her weight loss efforts.

Review of Pharmacologic Weight Loss Medications in a Patient-Centered Medical Home

Background: Per the Centers for Disease Control, 78 million adults were classified as obese in the United States in 2009 to 2010. Lifestyle modifications and pharmacologic treatment are appropriate options to combat obesity. Objectives: The primary objective of the study was to assess change in body weight after 12 weeks in patients seen at a family medicine patient-centered medical home (PCMH) who were prescribed Food and Drug Administration-approved weight loss medications. Methods: A retrospective medical record review was used to evaluate weight loss in adult patients with office visits at the PCMH. Adult patients were eligible for inclusion in the study if prescribed a Food and Drug Administration approved weight loss medication between July 1, 2013, and March 31, 2014, and had at least one weight documented during a follow-up visit 12 weeks after the initial prescription. Results: Of the 27 patients identified for study inclusion, 22 (81.5%) were prescribed phentermine. The remaining 5 (18.5%) patients were prescribed phentermine/topiramate ER. After 12 weeks of pharmacologic therapy, the median change in body weight was -3.7 kg (range = -16.8 to 5.5 kg) regardless of medication taken. This correlates to a -1.4 kg/m² (range = -15.7 to 4.2 kg/m²) median change in body mass index. Twelve patients (44.4%) lost at least 5% of their body weight during the study period. Conclusions: In our study population, we observed a median weight loss of 3.7 kg over 12 weeks while utilizing weight loss medications. Unfortunately, other lifestyle-modification services offered through the PCMH were not consistently utilized.

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.

Safety of antiobesity drugs

Obesity is a major health problem worldwide. Although diet and physical activity are crucial in the management of obesity, the long-term success rate is low. Therefore antiobesity drugs are of great interest, especially when lifestyle modification has failed. As obesity is not an immediate life-threatening disease, these drugs are required to be safe. Antiobesity drugs that have been developed so far have limited efficacies and considerable adverse effects affecting tolerability and safety. Therefore, most antiobesity drugs have been withdrawn. Fenfluramine and dexfenfluramine were withdrawn because of the potential damage to heart valves. Sibutramine was associated with an increase in major adverse cardiovascular events in the Sibutramine Cardiovascular Outcomes (SCOUT) trial and it was withdrawn from the market in 2010. Rimonabant was withdrawn because of significant psychiatric adverse effects. Orlistat was approved in Europe and the United States for long-term treatment of obesity, but many patients cannot tolerate its gastrointestinal side effects. Phentermine and diethylpropion can only be used for less than 12 weeks because the long-term safety of these drugs is unknown. Ephedrine and caffeine are natural substances but the effects on weight reduction are modest. As a result there is a huge unmet need for effective and safe antiobesity drugs. Recently lorcaserin and topiramate plus phentermine have been approved for the treatment of obesity but long-term safety data are lacking.

Pharmacotherapy for obesity: novel agents and paradigms

Public health initiatives focused on obesity prevention and lifestyle intervention programmes for patients with obesity have struggled to contain the obesity epidemic to date. In recent years, antiobesity drug therapies have had a limited role in clinical treatment algorithms for patients with obesity. Indeed, a number of high-profile antiobesity drug suspensions have markedly impacted upon the landscape of obesity pharmacotherapy. In this review, we discuss the advent of an increasing array of pharmacotherapeutic agents, which are effective both in inducing weight loss and in maintaining weight loss achieved by lifestyle measures. The development of these drugs as antiobesity agents has followed varying paths, ranging from lorcaserin, a selective serotonin agent, exploiting the beneficial central actions of fenfluramine but without the associated systemic side effects, to liraglutide, a gut hormone already used as a glucose-lowering drug but with appetite-suppressant properties, or the novel drug combination of phentermine/topiramate, two 'old' drugs used in lower doses than with previous therapeutic uses, resulting in an additive effect on weight loss and fewer side effects. We summarize the key findings from recent randomized controlled trials of these three drugs. Although these agents lead to clinically important weight loss when used as monotherapy, the use of antiobesity drugs as adjunctive therapy post intensive lifestyle intervention could prove to be the most successful strategy. Moreover, a progressive approach to obesity pharmacotherapy perhaps offers the best opportunity to finally address the obesity crisis on a mass scale.

Effects of anti-obesity drugs, phentermine and mahuang, on the behavioral patterns in Sprague-Dawley rat model

According to WHO global estimates from 2008, more than 1.4 billion adults were overweight and among them, over 200 million men and 300 million women were obese. Although the main treatment modalities for overweight and obese individuals remain dieting and physical exercise, the synthetic anti-obesity medications have been increasingly used due to their perceived convenience. Generally, anti-obesity medications are classified as appetite suppressants or fat absorption blockers. In the present study, we examined the adverse side-effects in respect of behavior changes of phentermine and Ephedra sinica (mahuang) that are anti-obesity drugs currently distributed to domestic consumers. Phentermine is mainly classified as an anorexing agent and mahuang a thermogenic agent. Because phentermine and mahuang are considered to display effectiveness through the regulation of nerve system, their potential influences of on behavioral changes were examined employing animal experiments. From the results of experiments testing locomotor activity through the use of treadmill, rota-rod, and open field system, phentermine and mahuang were commonly revealed to induce behavioral changes of rats by reducing a motor ability, an ability to cope with an external stimulus, and a sense of balance or by augmenting wariness or excitement. These adverse effects of phenternime and mahuang in behavioral changes need to be identified in humans and anti-obesity medications such as phentermine and mahuang should be prescribed for only obesity where it is anticipated that the benefits of the treatment outweigh their potential risks.

Body weight loss with phentermine alone versus phentermine and fenfluramine with very-low-calorie diet in an outpatient obesity management program: a retrospective study

BACKGROUND

Obesity, which is epidemic in the United States, is associated with increased morbidity and mortality. The combination of diet, exercise, and a behavior-modification program often does not result in ideal body weight.

OBJECTIVE

The aim of this study was to determine the efficacy of phentermine (Phen) alone compared with phentermine plus fenfluramine (Phen-Fen), when used in combination with a very-low-calorie diet (VLCD) for weight loss in an outpatient obesity center.

METHODS

We analyzed data collected at the UCLA outpatient University Obesity Center between 1993 and 1999. Data for patients who attended the center for at least 12 weeks and at least 4 visits, who were taking Phen or Phen-Fen, and whose body mass index (BMI) was ≥30 kg/m(2) were included in this retrospective study.

RESULTS

During the study period, 3200 visits were recorded. Of 1133 potential participants, 446 patients were included in the analysis (309 women, 137 men; mean [SD] age, 46.7 [11.4] years; mean [SEM] body weight, 109.6 [26.7] kg; mean [SEM] BMI, 38.0 [7.6] kg/m(2)). Of these, 128 women and 60 men (mean [SEM] body weight at baseline, 103.4 [24.0] kg and 124.9 [28.2] kg, respectively) received Phen alone; 181 women and 77 men (mean [SEM] body weight at baseline, 102.5 [21.4] kg and 124.9 [30.2] kg, respectively) received Phen-Fen. No statistically significant differences were found between the Phen and Phen-Fen groups in mean age, body weight, or BMI for women or men at baseline. No significant differences in the time of weight loss were found when a VLCD was used with Phen alone compared with the Phen-Fen combination for either sex even at 12 weeks. For women, the mean total body weight loss was 7.4% in the Phen group and 8.7% in the Phen-Fen group, but these differences were not significant. For men, the mean total body weight loss was 7.8% in the Phen group and 8.2% in the Phen-Fen group, but these differences were not significant. No significant differences in BMI, severe adverse events, or dropout rate were found between the 2 treatment groups for men or women.

CONCLUSIONS

This outpatient study did not detect any significant difference between adjunctive uses of Phen compared with Phen-Fen pharmacotherapy when used with VLCD over 12 weeks. Phen can be used to achieve significant weight loss when combined with VLCD. The tolerability and positive physical response further suggest that Phen is a valuable medication for obesity management in the outpatient setting.

New centrally acting agents for appetite control: from biological mechanisms to clinical efficacy

BACKGROUND

Obesity is one of the major problems of health policy in different countries. Pharmacological attempts have been made to help affected people without a definitive solution. Some agents--either with peripheral or central effect--are available in the market. On July 2012, the FDA approved two novel preparations for obese patients: (1) topiramate-phentermine--the first one an anticonvulsant and the second one a sympathomimetic amine--and (2) lorcaserin, a 5-HT2CR agonist. Both preparations emerged as new options for weight management.

SCOPE

Based on the complex biology of eating behavior, in this review we discuss the features, mechanisms of action, pharmacokinetics, advantages and possible disadvantages of these new agents.

CONCLUSION

With differences in efficacy (higher for the topiramate-phentermine combination), both preparations are active in reducing appetite and body weight, as well as in improving comorbidities. Additional information will be collected from Phase IV surveillance. Focus on cardiovascular, neuropsychiatric (for both introductions) and embrio-fetal safety (especially for topiramate) is expected.

Update on obesity pharmacotherapy

There are two groups of approved drugs that can be used to manage weight in patients with obesity: medications approved for obesity per se and medications that affect body weight for obese patients who have complications from their obesity and are receiving these medications for chronic disease management. For obesity per se, treatment is with one of the three drugs currently approved for long-term treatment of obesity or one of a few others that can be used for short-term treatment. Among these, orlistat partially blocks intestinal digestion of fat and produces weight loss of 5-8 kg but major limitations are associated gastrointestinal symptoms; lorcaserin, a serotonin-2C agonist with few side effects, produces a mean weight loss of 4-7 kg; and the combination of phentermine and topiramate (extended release) produces a mean weight loss of 8-10 kg, but should only be used after verifying a woman is not pregnant. Failure to lose more than 3% of body weight within 3 months with any of these agents should lead to reevaluation of therapy. The short-term drugs for treating obesity per se are sympathomimetics, with phentermine being most widely used. The second group of drugs is for weight-centric prescribing for patients with a chronic disease such as diabetes, depression, or psychiatric disorders. For each disorder, some drugs produce weight gain, others are weight neutral, but the best choice for these patients is the combination of drugs that treat the underlying condition and also produce weight loss.

Use of prescription antiobesity drugs in the United States

STUDY OBJECTIVE

To examine national trends in prescription antiobesity drug use in the United States.

DESIGN

Data analysis.

DATA SOURCE

The IMS Health Vector One National and Total Patient Tracker and Encuity Research Treatment Answers databases, the Source Healthcare Analytics Source Lx database, and IMS LifeLink database.

MEASUREMENTS AND MAIN RESULTS

National drug use estimates from 1991-2011 were extracted from the IMS Health Vector One National database, and patient characteristics from 2008-2011 were extracted from the Vector One Total Patient Tracker and Encuity Research Treatment Answers databases. The Source Healthcare Analytics Source Lx database was used to examine duration of antiobesity drug use from 2002-2011, with a sensitivity analysis performed using the IMS LifeLink database. In 2011, approximately 2.74 million patients used antiobesity drugs, predominantly phentermine (2.43 million patients). The use of prescription orlistat and sibutramine was relatively uncommon. Eighty-five percent of antiobesity drug users were female, 62% were aged 17-44 years, and 4.5% had a body mass index of ≤ 24.9 kg/m(2) . Duration of use was generally short and most patients only had one episode of antiobesity drug use during the observation period. The longest episode of use was 30 days or less in 47-58% of patients. Approximately one quarter of the patients used antiobesity drugs for longer than 90 days, including phentermine and other amphetamine congeners whose labels recommend short-term use, not exceeding "a few weeks." Only 1.3-4.2% of antiobesity drug users used them for longer than 1 year. Concomitant use of two or more prescription weight-loss drugs was generally uncommon, although phentermine was dispensed during 13-16% of benzphetamine, diethylpropion, or phendimetrazine episodes of use.

CONCLUSION

Phentermine dominated the prescription weight-loss market. Despite the indication of short-term use for amphetamine congeners, duration of use was similar to other antiobesity drugs. Nevertheless, the reasons for and implications of the limited duration of use observed with all prescription antiobesity drugs deserve further investigation.

Continuing education case study quiz

Goal- The goal of this program is to educate pharmacists about the use of elvitegravir/cobicistat/emtricitabine/tenofovir disoproxil fumarate (df) combination tablet for the treatment of HIV infection. Objectives-At the completion of this program, the reader will be able to:Describe the pharmacology and pharmacokinetics of elvitegravir/cobicistat/emtricitabine/tenofovir df combination.Discuss the risks associated with the use of elvitegravir/cobicistat/emtricitabine/tenofovir df combination.Discuss the potential benefit of elvitegravir/cobicistat/emtricitabine/tenofovir df combination for an individual patient.Apply the information on the use of elvitegravir/cobicistat/emtricitabine/tenofovir df combination to a case study.

Clinical utility of phentermine/topiramate (Qsymia™) combination for the treatment of obesity

Qsymia™ (Vivus Inc, Mountain View, CA, USA), a combination of phentermine and delayed-release topiramate, has been available in the US since September 2012 for the treatment of obesity. Phentermine is an anorexigenic agent, which is approved for the short-term treatment of obesity, while topiramate is approved for nonweight loss indications - seizure disorders and migraine prophylaxis. The amount of weight loss achieved with combination therapy is of a greater magnitude than what could be achieved with either agent alone. Adverse events that occur with the combination therapy are in line with the known side effect profiles of the constituent drugs; teratogenicity, a slight increase in heart rate, psychiatric and cognitive adverse effects, and metabolic acidosis are concerns.

A randomized, double-blind, placebo-controlled study of an oral, extended-release formulation of phentermine/topiramate for the treatment of obstructive sleep apnea in obese adults

STUDY OBJECTIVES

To evaluate safety and efficacy of phentermine 15 mg plus extended-release topiramate 92 mg for treatment of moderate to severe obstructive sleep apnea (OSA) in obese adults.

DESIGN

This phase 2, randomized, double-blind, placebo-controlled study included 2-week screening and 28-week treatment periods. Overnight polysomnography was performed at baseline, Week 8, and Week 28.

SETTING

Single-center study conducted from August 2008 to September 2009.

PARTICIPANTS

Forty-five subjects with moderate to severe OSA not receiving positive airway pressure (PAP) treatment with body mass index of 30-40 kg/m(2).

INTERVENTIONS

Subjects were randomized to receive placebo (n = 23) or phentermine 15 mg plus extended-release topiramate 92 mg (n = 22). Both groups received lifestyle-modification counseling.

MEASUREMENTS AND RESULTS

Primary endpoint, change in apnea-hypopnea index (AHI), significantly favored phentermine 15 mg plus extended-release topiramate 92 mg (-31.5 events/h, 95% CI: -40.0, -22.9) over placebo (-16.6 events/h, 95% CI: -25.0, -8.2) at Week 28 (P =0.0084). At Week 28, there was a 10.2% (95% CI: -12.7, -7.6; 10.8 kg, 95% CI: -13.5, -8.0) mean decrease in weight in the phentermine 15 mg plus extended-release topiramate 92 mg group compared with 4.3% (95% CI: -6.6, -2.0; 4.7 kg, 95% CI: -7.2, -2.2) in the placebo group (P = 0.0006) and a positive, significant (P = 0.0003) correlation between percent change in weight and change in AHI. Significant improvements in overnight oxygen saturation and reduction in blood pressure compared with placebo were observed. Phentermine 15 mg plus extended-release topiramate 92 mg was well tolerated with low adverse event rates.

CONCLUSIONS

Phentermine 15 mg plus extended-release topiramate 92 mg induced significant weight reductions and concomitant improvements in OSA and related symptoms vs placebo. This suggests weight loss mediated by phentermine 15 mg plus extended-release topiramate 92 mg may be useful in treatment of moderate to severe OSA in obese subjects unable or unwilling to comply with PAP treatment.

Phentermine plus topiramate for the treatment of obesity

A novel combination therapy is currently being investigated for the treatment of obesity. Phentermine plus topiramate has shown efficacy in both Phase II and III trials as compared with either drug used alone. With average 2-year weight loss as high as 10.5% and reduction of up to 76% in the incidence of progression of Type II diabetes, combination phentermine plus topiramate may provide significant benefit in conjunction with behavioral modification in the management of obesity. However, as with any new pharmacologic treatment option, the risk/benefit profile needs to be carefully assessed.

ACS chemical neuroscience molecule spotlight on Qnexa

Qnexa (VI-0521) is an investigational fixed-dose combination drug of phentermine and topiramate currently in Phase III clinical trials for the treatment of obesity. Vivus, Inc. has demonstrated efficacy of their product and are currently addressing FDA safety concerns with the possibility of a New Drug Application (NDA) resubmission.

Combinations of drugs in the Treatment of Obesity

Obesity is a chronic disease associated with excess morbidity and mortality. Clinical treatment, however, currently offers disappointing results, with very high rates of weight loss failure or weight regain cycles, and only two drugs (orlistat and sibutramine) approved for long-term use. Drugs combinations can be an option for its treatment but, although widely used in clinical practice, very few data are available in literature for its validation. Our review focuses on the rationale for their use, with advantages and disadvantages; on combinations often used, with or without studies; and on new perspectives of combinations being studied mainly by the pharmaceutical industry.