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Hormones (Athens, Greece) 2013Very few drugs are approved for obesity treatment by regulatory agencies. Very recently phentermine/topiramate controlled-release [PHEN/TPM CR; (Qsymia®)] obtained Food... (Review)
Review
BACKGROUND AND OBJECTIVE
Very few drugs are approved for obesity treatment by regulatory agencies. Very recently phentermine/topiramate controlled-release [PHEN/TPM CR; (Qsymia®)] obtained Food and Drug Administration (FDA) approval as an addition to a reduced-calorie diet and exercise for chronic weight management. Our aim was to review the available clinical evidence on weight loss, metabolic effects and adverse events associated with use of this product.
METHODS
Randomized controlled trials with phentermine/topiramate controlled-release were selected through a Medline search using the terms: phentermine and topiramate, phentermine and controlled release topiramate, new anti-obesity drugs and phentermine/topiramate, recent combinations of anti-obesity drugs and Qnexa®.
RESULTS
PHEN/TPM CR was associated with a weight loss of 8.1-10.9 % (mid and high dose, respectively), while patients in placebo groups lost 1.4-1.8 % of their initial weight. PHEN/TPM CR also resulted in a significant decrease of waist circumference. Weight loss with PHEN/TPM CR was associated with a decrease in blood pressure but with a slight increase in the heart rate. Furthermore, in all trials it exerted favorable effects on lipid profile, especially on triglycerides and high-density lipopoprotein (HDL) cholesterol. PHEN/TPM CR treatment also improved insulin sensitivity and glycemia. Moreover, it decreased significantly progression to type 2 diabetes. In all of the studies the severe adverse events were similar between the control groups and the groups of PHEN/TPM CR. The most frequent side-effects observed in the active treatment group were paresthesia, dysgeusia, dry mouth, constipation and insomnia.
WHAT IS NEW AND CONCLUSION
PHEN/TPM CR combined with lifestyle modification may be an effective and well-tolerated treatment for obesity and weight-related metabolic complications. Its long-term efficacy and safety have yet to be defined.
Topics: Anti-Obesity Agents; Delayed-Action Preparations; Diet, Reducing; Drug Therapy, Combination; Exercise; Fructose; Humans; Life Style; Obesity; Phentermine; Topiramate; Treatment Outcome; Weight Loss
PubMed: 24457398
DOI: 10.14310/horm.2002.1438 -
The British Journal of Psychiatry : the... Mar 1990
Topics: Adult; Female; Humans; Paranoid Disorders; Phentermine; Trifluoperazine
PubMed: 2346853
DOI: 10.1192/bjp.156.3.442 -
International Journal of Obesity and... Jul 1999'Fen-phen' refers to the off-label combination of the appetite suppressants fenfluramine and phentermine. The rationale for the fen-phen combination was that the two... (Review)
Review
'Fen-phen' refers to the off-label combination of the appetite suppressants fenfluramine and phentermine. The rationale for the fen-phen combination was that the two drugs exerted independent actions on brain satiety mechanisms so that it was possible to use lower doses of each drug and yet retain a common action on suppressing appetite while minimizing adverse drug effects. The focus of the present review is to consider whether fenfluramine and phentermine exert actions that are additive in nature or whether these two drugs exhibit drug-drug synergism. The fen-phen combination results in synergism for the suppression of appetite and body weight, the reduction of brain serotonin levels, pulmonary vasoconstriction and valve disease. Fen-phen synergism may reflect changes in the pharmacokinetics of drug distribution, common actions on membrane ion currents, or interactions between neuronal release and reuptake mechanisms with MAO-mediated transmitter degradation. The synergism between fenfluramine and phentermine highlights the need to more completely understand the pharmacology and neurochemistry of appetite suppressants prior to use in combination pharmacotherapy for the treatment of obesity.
Topics: Animals; Appetite; Appetite Depressants; Body Weight; Brain; Drug Synergism; Drug Therapy, Combination; Energy Intake; Fenfluramine; Humans; Monoamine Oxidase Inhibitors; Phentermine; Selective Serotonin Reuptake Inhibitors
PubMed: 10454106
DOI: 10.1038/sj.ijo.0800920 -
BMJ Case Reports Mar 2017Acute interstitial nephritis (AIN) has a number of medication-related aetiologies. Antibiotics, proton pump inhibitors and non-steroidal anti-inflammatory drugs are...
Acute interstitial nephritis (AIN) has a number of medication-related aetiologies. Antibiotics, proton pump inhibitors and non-steroidal anti-inflammatory drugs are common causes; however, any medication has the potential to cause drug-induced AIN. We report the first case of phentermine-induced AIN. A Caucasian woman aged 43 years presented with a 5-week history of lethargy, left-sided lower abdominal pain, nausea and vomiting. She had been taking phentermine for weight loss for 9 months and had recently ceased the medication. The patient underwent a renal biopsy that showed a predominantly lymphohistiocytic interstitial infiltrate with a moderate number of eosinophils consistent with AIN. Phentermine is increasingly used for weight loss in obese patients. This is the first case implicating phentermine as the causative agent for drug-induced AIN. While rare, phentermine-induced AIN is a possible adverse reaction of phentermine. Physicians and patients need to be aware of this risk.
Topics: Adult; Female; Humans; Nephritis, Interstitial; Obesity; Phentermine
PubMed: 28280086
DOI: 10.1136/bcr-2017-219452 -
Journal of the Neurological Sciences Oct 2018
Topics: Appetite Depressants; Brain; Cerebral Hemorrhage; Female; Humans; Middle Aged; Obesity; Phentermine; Recurrence
PubMed: 30179740
DOI: 10.1016/j.jns.2018.08.017 -
Annals of Plastic Surgery Oct 2018Phentermine is the most prescribed antiobesity drug in America, with 2.43 million prescriptions written in 2011. Case reports suggest there are anesthetic risks, such as...
PURPOSE
Phentermine is the most prescribed antiobesity drug in America, with 2.43 million prescriptions written in 2011. Case reports suggest there are anesthetic risks, such as refractory hypotension, involved with its perioperative use. Despite these risks and the frequency of phentermine use among plastic surgery patients, there are no published guidelines for the perioperative management of phentermine use in the plastic surgery literature. To address this patient safety issue, we performed a systematic review and provide management recommendations.
METHODS
A systematic review of the pharmacology of phentermine and the anesthetic risks involved with its perioperative use was undertaken using the search engines PubMed/MEDLINE, EMBASE, and Scopus.
RESULTS
A total of 251 citations were reviewed, yielding 4 articles that discussed perioperative phentermine use and complications with anesthesia. One was a review article, 2 were case reports, and 1 was a letter. Complications included hypotension, hypertension, hypoglycemia, hyperthermia, bradycardia, cardiac depression, and acute pulmonary edema.
CONCLUSIONS
The relationship between phentermine and anesthesia, if any, is unclear. Hypotension on induction of general anesthesia is the most reported complication of perioperative phentermine use. Specifically, phentermine-induced hypotension may be unresponsive to vasopressors that rely on catecholamine release, such as ephedrine. Therefore, the decision to perform surgery, especially elective surgery, in a patient taking phentermine should be made with caution. Because of the half-life of phentermine, we recommend discontinuing phentermine for at least 4 days prior to surgery. This differs from the classic 2-week discontinuation period recommended for "fen-phen." The patient should be made aware of the increased risk of surgery, and a skilled anesthesiologist should monitor intraoperative blood pressure and body temperature for signs of autonomic derailment.
Topics: Anesthesia; Anesthetics; Appetite Depressants; Drug Interactions; Humans; Phentermine; Plastic Surgery Procedures
PubMed: 30204622
DOI: 10.1097/SAP.0000000000001478 -
Archives Internationales de... Mar 1969
Comparative Study
Topics: Amphetamine; Animals; Appetite; Appetite Depressants; Blood Pressure; Body Weight; Cardiovascular System; Dextroamphetamine; Drug Synergism; Heart Rate; Mice; Phenethylamines; Phenoxybenzamine; Phentermine; Propranolol; Rats; Reserpine; Tachyphylaxis
PubMed: 5353475
DOI: No ID Found -
Expert Opinion on Drug Safety Jan 2017Few studies on combination therapies for the treatment of obesity had been conducted until recently, when two fixed-dose combinations, bupropion-naltrexone ER fixed-dose... (Review)
Review
Few studies on combination therapies for the treatment of obesity had been conducted until recently, when two fixed-dose combinations, bupropion-naltrexone ER fixed-dose combination and phentermine-topiramate ER titrated-dose combinations were evaluated in clinical studies that ultimately led to FDA approval. Areas covered: In this review, we discuss safety concerns about both combinations, the rationale and history of combination therapies for obesity (including phentermine plus fenfluramine), and possible future new combinations. Expert opinion: Combination therapies are a promising new area in obesity treatment, similar to what occurs with diabetes and hypertension. Safety assessment is highly important due to the high number of potential users on a chronic basis.
Topics: Animals; Anti-Obesity Agents; Bupropion; Delayed-Action Preparations; Drug Combinations; Fructose; Humans; Naltrexone; Obesity; Phentermine; Topiramate
PubMed: 27732121
DOI: 10.1080/14740338.2017.1247807 -
The Australian and New Zealand Journal... Aug 2011
Topics: Adult; Female; Humans; Male; Middle Aged; Phentermine; Psychoses, Substance-Induced
PubMed: 21595510
DOI: 10.3109/00048674.2011.580721 -
Journal of Managed Care Pharmacy : JMCP Oct 2013Obesity may lead to the development of multiple chronic disease states, including hypertension, dyslipidemia, and type 2 diabetes mellitus. Over a half billion adults... (Review)
Review
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.
Topics: Adult; Anti-Obesity Agents; Appetite Depressants; Benzazepines; Body Weight; Clinical Trials, Phase III as Topic; Female; Fructose; Humans; Male; Obesity; Phentermine; Randomized Controlled Trials as Topic; Topiramate; Weight Loss
PubMed: 24074010
DOI: 10.18553/jmcp.2013.19.8.642