Valvular regurgitation and surgery associated with fenfluramine use: an analysis of 5743 individuals

Benfluorex metabolism complemented by electrochemistry-mass spectrometry

The hypolipidemic and hypoglycemic drug benfluorex was widely applied to treat type 2 diabetes mellitus and metabolic syndrome in overweight patients since 1976. However, benfluorex was connected to multiple cases of valvular heart disease and pulmonary arterial hypertension later on. Similar adverse drug reactions were previously found to be associated to the structurally related drug fenfluramine, which was attributed to the formation of its N-deethylated metabolite norfenfluramine. Even though norfenfluramine was known to be a common metabolite of fenfluramine and benfluorex, only fenfluramine was withdrawn from European and United States markets in 1997 while benfluorex remained available until 2009. In this work, the metabolism of benfluorex is simulated by an online hyphenation of electrochemistry and mass spectrometry and the observed transformation products are further characterized using liquid chromatography and high-resolution tandem mass spectrometry. Using this approach, norfenfluramine is found to be the main electrochemical transformation product of benfluorex. Considering the knowledge about norfenfluramine toxicity, rapid metabolite screening using electrochemistry hyphenated to mass spectrometry could have been used to predict the potential of benfluorex for adverse drug reactions early on, showcasing the value of electrochemical metabolism mimicry for rapid drug safety evaluation.

Reintroducing Fenfluramine as a Treatment for Seizures: Current Knowledge, Recommendations and Gaps in Understanding

Despite the introduction of new anti-seizure medications in recent years, approximately one-third of the epileptic population continues to experience seizures. Recently, the anti-obesity medication fenfluramine (FFA) has been successfully repurposed, and it has received approval from various regulatory agencies for the treatment of seizures associated with Dravet syndrome and Lennox-Gastaut syndrome. The potential antiseizure effects of FFA were initially observed in patients with photosensitive epilepsy in the 1980s but it was not rigorously explored as a treatment option until 30 years later. This narrative review aims to provide an overview of the historical progression of FFA's use, starting from initial clinical observations to preclinical studies and, ultimately, successful clinical trials in the field of epilepsy.

The risk of chronic psychedelic and MDMA microdosing for valvular heart disease

Psychedelic microdosing is the practice of taking very low doses of psychedelic substances, typically over a longer period of time. The long-term safety of chronic microdosing is relatively uncharacterized, but valvular heart disease (VHD) has been proposed as a potential risk due to activation of the serotonin 5-HT2B receptor. However, this risk has not yet been comprehensively assessed. This analysis searched for all relevant in vitro, animal, and clinical studies related to the VHD risk of lysergic acid diethylamide (LSD), psilocybin, mescaline, N,N-dimethyltryptamine (DMT), and the non-psychedelic 3,4-methylenedioxymethamphetamine (MDMA). All five compounds and some metabolites could bind to the 5-HT2B receptor with potency equal to or greater than that of the 5-HT2A receptor, the primary target of psychedelics. All compounds were partial agonists at the 5-HT2B receptor with the exception of mescaline, which could not be adequately assessed due to low potency. Safety margins relative to the maximum plasma concentrations from typical microdoses were greater than known valvulopathogens, but not without potential risk. No animal or clinical studies appropriately designed to evaluate VHD risk were found for the four psychedelics. However, there is some clinical evidence that chronic ingestion of full doses of MDMA is associated with VHD. We conclude that VHD is a potential risk with chronic psychedelic microdosing, but further studies are necessary to better define this risk.

Binding and functional structure-activity similarities of 4-substituted 2,5-dimethoxyphenyl isopropylamine analogues at 5-HT2A and 5-HT2B serotonin receptors

Certain 4-substituted analogs of 1-(2,5-dimethoxyphenyl)isopropylamine (2,5-DMA) are psychoactive classical hallucinogens or serotonergic psychedelic agents that function as human 5-HT_2A (h5-HT_2A) serotonin receptor agonists. Activation of a related receptor population, h5-HT_2B receptors, has been demonstrated to result in adverse effects including cardiac valvulopathy. We previously published on the binding of several such agents at the two receptor subtypes. We hypothesized that, due to their structural similarity, the 5-HT_2A and 5-HT_2B receptor affinities of these agents might be related, and that QSAR studies might aid future studies. For a series of 13 compounds, it is demonstrated here that i) their published rat brain 5-HT₂ receptor affinities are significantly correlated with their h5-HT_2A (r = 0.942) and h5-HT_2B (r = 0.916) affinities, ii) as with r5-HT₂ receptor affinity, h5-HT_2A affinity is correlated with the lipophilicity of the 4-position substituent (r = 0.798), iii) that eight of the ten compounds examined in functional (Ca⁺² mobilization in stable cell lines generated expressing the human 5-HT_2B receptor using the Flp-In T-REx system) assays acted as h5-HT_2B agonists (4-substituent = H, F, Br, I, OCH₂CH₃, NO₂, nC₃H₇, tC₄H₉) and two (n-hexyl and benzyl) as antagonists, iv) h5-HT_2B affinity but not action was correlated with the lipophilicity of the 4-position substituent (r = 0.750; n = 10). The findings suggest that h5-HT_2B receptor affinity, and its relationship to substituent lipophilicity, might be approximated by rat and h5-HT_2A affinity but cannot be used as a predictor of h5-HT_2B agonist action of 2,5-DMA analogs. Furthermore, given that certain 2,5-DMA analogs are on the clandestine market, their potential to produce cardiac side effects following persistent or chronic use via activation of h5-HT_2B receptors should be considered.

Fenfluramine: A Review of Pharmacology, Clinical Efficacy, and Safety in Epilepsy

Despite the availability of more than 30 antiseizure medications (ASMs), the proportion of patients who remain refractory to ASMs remains static. Refractory seizures are almost universal in patients with epileptic encephalopathies. Since many of these patients are not candidates for curative surgery, there is always a need for newer ASMs with better efficacy and safety profile. Recently, the anti-obesity medication fenfluramine (FFA) has been successfully repurposed, and various regulatory agencies approved it for seizures associated with Dravet and Lennox–Gastaut syndromes. However, there is a limited in-depth critical review of FFA to facilitate its optimal use in a clinical context. This narrative review discusses and summarizes the antiseizure mechanism of action of FFA, clinical pharmacology, and clinical studies related to epilepsy, focusing on efficacy and adverse effects.

Long-term cardiovascular safety of fenfluramine in patients with Dravet syndrome treated for up to 3 years: Findings from serial echocardiographic assessments

OBJECTIVE

To assess the cardiovascular safety of fenfluramine when used to treat children and young adults with Dravet syndrome.

METHODS

Patients with Dravet syndrome who completed one of three phase 3 clinical trials of fenfluramine could enroll in the open-label extension (OLE) study (NCT02823145). All patients started fenfluramine treatment at an oral dose of 0.2 mg/kg/day. The dose was titrated based on efficacy and tolerability to a maximum of 0.7 mg/kg/day (absolute maximum 26 mg/day) or 0.4 mg/kg/day (absolute maximum 17 mg/day) in patients concomitantly receiving stiripentol. Serial transthoracic echocardiography was performed using standardized methods and blinded readings at OLE entry, after 4-6 weeks, and every 3 months thereafter. Valvular heart disease (VHD) was defined as ≥ moderate mitral regurgitation or ≥ mild aortic regurgitation combined with physical signs or symptoms attributable to valve dysfunction. Pulmonary artery hypertension (PAH) was defined as systolic pulmonary artery pressure >35 mmHg.

RESULTS

A total of 327 patients (median age, 9.0 years; range, 2-19 years) have enrolled in the OLE and received ≥1 dose of fenfluramine. The median duration of treatment was 23.9 months (range, 0.2-42.6 months) and the median dose of fenfluramine was 0.44 mg/kg/day. No patient demonstrated VHD or PAH at any time during the OLE.

SIGNIFICANCE/INTERPRETATION

This study, which represents the largest, longest, and most rigorous examination of cardiovascular safety of fenfluramine yet reported, found no cases of VHD or PAH. These results, combined with fenfluramine's substantial antiseizure efficacy, support a strong positive benefit-risk profile for fenfluramine in the treatment of Dravet syndrome.

Cardiac adverse effects of antiseizure medications

INTRODUCTION

Patients with severe epilepsy are at increased risk of cardiovascular disease and arrhythmias. Although antiseizure medications (ASMs) may have indirect protective effects against cardiovascular events by reducing seizure frequency and hence sudden death in epilepsy, some of them exert cardiotoxic effects.

AREAS COVERED

Patients with epilepsy, mainly those with severe forms, are at higher risk of cardiac disease because their heart can have structural alterations and electrical instability as a consequence of repeated seizures. Some ASMs have direct protective effects through anti-inflammatory, antioxidant, hypotensive, and lipid-reducing properties. Antiseizure medications can also have toxic cardiac effects including both long-term consequences, such as the increased risk of atherogenesis and subsequent cardiovascular disease due to the influence on lipid profile and pro-inflammatory milieu, and immediate effects as the increased risk of potentially fatal arrhythmias due to the influence on ion channels. Sodium channel blocking ASMs may also affect cardiac sodium channels and this effect is particularly observed in subjects with genetic mutations in cardiac ion channels. Fenfluramine cause valvulopathies in obese subjects and this effect need to be evaluated in epilepsy patients.

EXPERT OPINION

For the selection of treatment, cardiotoxic effects of ASMs should be considered; cardiac monitoring of treatment is advisable.

Fenfluramine repurposing from weight loss to epilepsy: What we do and do not know

In 2020, racemic-fenfluramine was approved in the U.S. and Europe for the treatment of seizures associated with Dravet syndrome, through a restricted/controlled access program aimed at minimizing safety risks. Fenfluramine had been used extensively in the past as an appetite suppressant, but it was withdrawn from the market in 1997 when it was found to cause cardiac valvulopathy. Available evidence indicates that appetite suppression and cardiac valvulopathy are mediated by different serotonergic mechanisms. In particular, appetite suppression can be ascribed mainly to the enantiomers d-fenfluramine and d-norfenfluramine, the primary metabolite of d-fenfluramine, whereas cardiac valvulopathy can be ascribed mainly to d-norfenfluramine. Because of early observations of markedly improved seizure control in some forms of epilepsy, fenfluramine remained available in Belgium through a Royal Decree after 1997 for use in a clinical trial in patients with Dravet syndrome at average dosages lower than those generally prescribed for appetite suppression. More recently, double-blind placebo-controlled trials established its efficacy in the treatment of convulsive seizures associated with Dravet syndrome and of drop seizures associated with Lennox-Gastaut syndrome, at doses up to 0.7 mg/kg/day (maximum 26 mg/day). Although no cardiovascular toxicity has been associated with the use of fenfluramine in epilepsy, the number of patients exposed to date has been limited and only few patients had duration of exposure longer than 3 years. This article analyzes available evidence on the mechanisms involved in fenfluramine-induced appetite suppression, antiseizure effects and cardiovascular toxicity. Despite evidence that stimulation of 5-HT_2B receptors (the main mechanism leading to cardiac valvulopathy) is not required for antiseizure activity, there are many critical gaps in understanding fenfluramine's properties which are relevant to its use in epilepsy. Particular emphasis is placed on the remarkable lack of publicly accessible information about the comparative activity of the individual enantiomers of fenfluramine and norfenfluramine in experimental models of seizures and epilepsy, and on receptors systems considered to be involved in antiseizure effects. Preliminary data suggest that l-fenfluramine retains prominent antiseizure effects in a genetic zebrafish model of Dravet syndrome. If these findings are confirmed and extended to other seizure/epilepsy models, there would be an incentive for a chiral switch from racemic-fenfluramine to l-fenfluramine, which could minimize the risk of cardiovascular toxicity and reduce the incidence of adverse effects such as loss of appetite and weight loss.

Targeting the 5-HT system: Potential side effects

Targeting the serotonin (5-HT) system is no simple task: there are at least 15 5-HT receptors, in addition to a number of transporters and metabolizing enzymes. Multiple 5-HT receptor variants exist due to genetic variations and/or post translational modifications, splice variants or editing variants. Some receptors may form homo and heteromers. The 5-HT system is targeted by multiple drugs to treat a variety of diseases. Given the homology amongst the 5-HT and neighbouring receptor classes, only few drugs are actually selective for a single target. In fact, many 5-HT drugs act on a combination of targets, i.e. several receptors and/or transporters or enzymes. For instance, a number of antidepressants or antipsychotics act on 5-HT and other transmitter systems. Recently developed drugs may show target selectivity by design, based on the current state of knowledge, whereas many older compounds hit multiple targets since they were developed using phenotypic screens, as was done well into the 1980's. Ergot analogues, antipsychotics or antidepressants, fall into this category. As our knowledge developed over the last 25-30 years, some targets have very well-defined liabilities: for instance, 5HT_2B or 5-HT_2A receptor agonists, will produce valvulopathies or hallucinations, respectively, whereas 5-HT₃ receptor antagonists, may lead to constipation. This short review will be limited in scope as there are multiple targets and even more compounds to discuss. This article is part of the special issue entitled 'Serotonin Research: Crossing Scales and Boundaries'.

Serotonin receptor type 2B activation augments TNF-α-induced matrix mineralization in murine valvular interstitial cells

Calcification, fibrosis, and chronic inflammation are the predominant features of calcific aortic valve disease, a life-threatening condition. Drugs that induce serotonin (5-hydroxytryptamine [5-HT]) are known to damage valves, and activated platelets, which carry peripheral serotonin, are known to promote calcific aortic valve stenosis. However, the role of 5-HT in valve leaflet pathology is not known. We tested whether serotonin mediates inflammation-induced matrix mineralization in valve cells. Real-time reverse transcription-polymerase chain reaction analysis showed that murine aortic valve interstitial cells (VICs) expressed both serotonin receptor types 2A and 2B (Htr2a and Htr2b). Although Htr2a expression was greater at baseline, Htr2b expression was induced several-fold more than Htr2a in response to the pro-calcific tumor necrosis factor-α (TNF-α) treatment. 5-HT also augmented TNF-α-induced osteoblastic differentiation and matrix mineralization of VIC, but 5-HT alone had no effects. Inhibition of serotonin receptor type 2B, using specific inhibitors or lentiviral knockdown in VIC, attenuated 5-HT effects on TNF-α-induced osteoblastic differentiation and mineralization. 5-HT treatment also augmented TNF-α-induced matrix metalloproteinase-3 expression, which was also attenuated by Htr2b knockdown. Htr2b expression in aortic roots and serum levels of peripheral 5-HT were also greater in the hyperlipidemic Apoe^-/- mice than in control normolipemic mice. These findings suggest a new role for serotonin signaling in inflammation-induced calcific valvulopathy.

Cardiovascular safety of fenfluramine in the treatment of Dravet syndrome: Analysis of an ongoing long-term open-label safety extension study

Objective

Fenfluramine, which was previously approved as a weight loss drug, was withdrawn in 1997 when reports of cardiac valvulopathy emerged. The present study was conducted in part to characterize the cardiovascular safety profile of low‐dose fenfluramine when used in a pediatric population to reduce seizure frequency in patients with Dravet syndrome.

Methods

Patients 2‐ to 18‐years‐old with Dravet syndrome who had completed any of three randomized, placebo‐controlled clinical trials of fenfluramine were offered enrollment in this open‐label extension (OLE) study. All patients were treated with fenfluramine starting at a dose of 0.2 mg/kg/day (oral solution dosed twice per day), which was titrated to maximal effect with a dose limit of 0.7 mg/kg/day (maximum 26 mg/day) or 0.4 mg/kg/day (maximum 17 mg/day) in patients receiving concomitant stiripentol. Standardized echocardiographic examinations were conducted at Week 4 or 6 and then every 3 months during the OLE study to monitor cardiac valve function and structure and pulmonary artery pressure. The primary end point for the echocardiography analysis was the number of patients who developed valvular heart disease or pulmonary artery hypertension (PAH) during treatment.

Results

A total of 232 patients were enrolled in the study. The average age of patients was 9.1 ± 4.7 years, and 55.2% were male. The median duration of treatment with fenfluramine was 256 days (range = 58‐634 days), and the mean dose of fenfluramine was 0.41 mg/kg/day. No cases of valvular heart disease or PAH were observed.

Significance

Longitudinal echocardiography over a median 8.4 months of treatment with fenfluramine suggests a low risk of developing cardiac valvulopathy and PAH when used to treat pediatric patients with Dravet syndrome.

"Pure" severe aortic stenosis without concomitant valvular heart diseases: echocardiographic and pathophysiological features

Purpose

In echocardiography the severity of aortic stenosis (AS) is defined by effective orifice area (EOA), mean pressure gradient (mPG_AV) and transvalvular flow velocity (maxV_AV). The hypothesis of the present study was to confirm the pathophysiological presence of combined left ventricular hypertrophy (LVH), diastolic dysfunction (DD) and pulmonary artery hypertension (PAH) in patients with “pure” severe AS.

Methods and Results

Patients (n = 306) with asymptomatic (n = 133) and symptomatic (n = 173) “pure” severe AS (mean age 78 ± 9.5 years) defined by indexed EOA < 0.6 cm² were enrolled between 2014 and 2016. AS patients were divided into 4 subgroups according to mPG_AV and indexed left ventricular stroke volume: low flow (LF) low gradient (LG)-AS (n = 133), normal flow (NF) LG-AS (n = 91), LF high gradient (HG)-AS (n = 21) and NFHG-AS (n = 61). Patients with “pure” severe AS showed mean mPG_AV of 31.7 ± 9.1 mmHg and mean maxV_AV of 3.8 ± 0.6 m/s. Only 131 of 306 patients (43%) exhibited mPG_AV > 40 mmHg and maxV_AV > 4 m/s documenting incongruencies of the AS severity assessment by Doppler echocardiography. LVH was documented in 81%, DD in 76% and PAH in 80% of AS patients. 54% of “pure” AS patients exhibited all three alterations. Ranges of mPG_AV and maxV_AV were higher in patients with all three alterations compared to patients with less than three. 224 (73%) patients presented LG-conditions and 82 (27%) HG-conditions. LVH was predominant in NF-AS (p = 0.014) and PAH in LFHG-AS (p = 0.014). Patients’ treatment was retrospectively assessed (surgery: n = 100, TAVI: n = 48, optimal medical treatment: n = 156).

Conclusion

In patients with “pure” AS according to current guidelines the presence of combined LVH, DD and PAH as accepted pathophysiological sequelae of severe AS cannot be confirmed. Probably, the detection of these secondary cardiac alterations might improve the diagnostic algorithm to avoid overestimation of AS severity.

Fenfluramine for Treatment-Resistant Seizures in Patients With Dravet Syndrome Receiving Stiripentol-Inclusive Regimens: A Randomized Clinical Trial

Importance

Fenfluramine treatment may reduce monthly convulsive seizure frequency in patients with Dravet syndrome who have poor seizure control with their current stiripentol-containing antiepileptic drug regimens.

Objective

To determine whether fenfluramine reduced monthly convulsive seizure frequency relative to placebo in patients with Dravet syndrome who were taking stiripentol-inclusive regimens.

Design, Setting, and Participants

This double-blind, placebo-controlled, parallel-group randomized clinical trial was conducted in multiple centers. Eligible patients were children aged 2 to 18 years with a confirmed clinical diagnosis of Dravet syndrome who were receiving stable, stiripentol-inclusive antiepileptic drug regimens.

Interventions

Patients with 6 or more convulsive seizures during the 6-week baseline period were randomly assigned to receive fenfluramine, 0.4 mg/kg/d (maximum, 17 mg/d), or a placebo. After titration (3 weeks), patients' assigned dosages were maintained for 12 additional weeks. Caregivers recorded seizures via a daily electronic diary.

Main Outcomes and Measures

The primary efficacy end point was the change in mean monthly convulsive seizure frequency between fenfluramine and placebo during the combined titration and maintenance periods relative to baseline.

Results

A total of 115 eligible patients were identified; of these, 87 patients (mean [SD], age 9.1 [4.8] years; 50 male patients [57%]; mean baseline frequency of seizures, approximately 25 convulsive seizures per month) were enrolled and randomized to fenfluramine, 0.4 mg/kg/d (n = 43) or placebo (n = 44). Patients treated with fenfluramine achieved a 54.0% (95% CI, 35.6%-67.2%; P < .001) greater reduction in mean monthly convulsive seizure frequency than those receiving the placebo. With fenfluramine, 54% of patients demonstrated a clinically meaningful (≥50%) reduction in monthly convulsive seizure frequency vs 5% with placebo (P < .001). The median (range) longest seizure-free interval was 22 (3.0-105.0) days with fenfluramine and 13 (1.0-40.0) days with placebo (P = .004). The most common adverse events were decreased appetite (19 patients taking fenfluramine [44%] vs 5 taking placebo [11%]), fatigue (11 [26%] vs 2 [5%]), diarrhea (10 [23%] vs 3 [7%]), and pyrexia (11 [26%] vs 4 [9%]). Cardiac monitoring demonstrated no clinical or echocardiographic evidence of valvular heart disease or pulmonary arterial hypertension.

Conclusions and Relevance

Fenfluramine demonstrated significant improvements in monthly convulsive seizure frequency in patients with Dravet syndrome whose conditions were insufficiently controlled with stiripentol-inclusive antiepileptic drug regimens. Fenfluramine was generally well tolerated. Fenfluramine may represent a new treatment option for Dravet syndrome.

Trial Registration

ClinicalTrials.gov identifier: NCT02926898.

Fenfluramine hydrochloride for the treatment of seizures in Dravet syndrome: a randomised, double-blind, placebo-controlled trial

BACKGROUND

Dravet syndrome is a rare, treatment-resistant developmental epileptic encephalopathy characterised by multiple types of frequent, disabling seizures. Fenfluramine has been reported to have antiseizure activity in observational studies of photosensitive epilepsy and Dravet syndrome. The aim of the present study was to assess the efficacy and safety of fenfluramine in patients with Dravet syndrome.

METHODS

In this randomised, double-blind, placebo-controlled clinical trial, we enrolled children and young adults with Dravet syndrome. After a 6-week observation period to establish baseline monthly convulsive seizure frequency (MCSF; convulsive seizures were defined as hemiclonic, tonic, clonic, tonic-atonic, generalised tonic-clonic, and focal with clearly observable motor signs), patients were randomly assigned through an interactive web response system in a 1:1:1 ratio to placebo, fenfluramine 0·2 mg/kg per day, or fenfluramine 0·7 mg/kg per day, added to existing antiepileptic agents for 14 weeks. The primary outcome was the change in mean monthly frequency of convulsive seizures during the treatment period compared with baseline in the 0·7 mg/kg per day group versus placebo; 0·2 mg/kg per day versus placebo was assessed as a key secondary outcome. Analysis was by modified intention to treat. Safety analyses included all participants who received at least one dose of study medication. This trial is registered with ClinicalTrials.gov with two identical protocols NCT02682927 and NCT02826863.

FINDINGS

Between Jan 15, 2016, and Aug 14, 2017, we assessed 173 patients, of whom 119 patients (mean age 9·0 years, 64 [54%] male) were randomly assigned to receive either fenfluramine 0·2 mg/kg per day (39), fenfluramine 0·7 mg/kg per day (40) or placebo (40). During treatment, the median reduction in seizure frequency was 74·9% in the fenfluramine 0·7 mg/kg group (from median 20·7 seizures per 28 days to 4·7 seizures per 28 days), 42·3% in the fenfluramine 0·2 mg/kg group (from median 17·5 seizures per 28 days to 12·6 per 28 days), and 19·2% in the placebo group (from median 27·3 per 28 days to 22·0 per 28 days). The study met its primary efficacy endpoint, with fenfluramine 0·7 mg/kg per day showing a 62·3% greater reduction in mean MCSF compared with placebo (95% CI 47·7-72·8, p<0·0001); fenfluramine 0·2 mg/kg per day showed a 32·4% reduction in mean MCSF compared with placebo (95% CI 6·2-52·3, p=0·0209). The most common adverse events (occurring in at least 10% of patients and more frequently in the fenfluramine groups) were decreased appetite, diarrhoea, fatigue, lethargy, somnolence, and decreased weight. Echocardiographic examinations revealed valve function within the normal physiological range in all patients during the trial and no signs of pulmonary arterial hypertension.

INTERPRETATION

In Dravet syndrome, fenfluramine provided significantly greater reduction in convulsive seizure frequency compared with placebo and was generally well tolerated, with no observed valvular heart disease or pulmonary arterial hypertension. Fenfluramine could be an important new treatment option for patients with Dravet syndrome.

FUNDING

Zogenix.

Phentermine: A Systematic Review for Plastic and Reconstructive Surgeons

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.

Serotonin levels and 1-year mortality in patients with neuroendocrine tumors: a systematic review and meta-analysis

Aim: Elevated serotonin in patients with neuroendocrine tumors (NETs) may impact heart failure incidence but a quantitative relationship has not been established. Materials & methods: Systematic review and meta-analysis of studies assessing 24-h urinary 5-hydroxyindoleacetic acid (u5-HIAA) and mortality in patients with NETs (2007-2017) with a primary outcome of 1-year mortality risk and 24-h u5-HIAA. Results: We identified 1715 records of which 12 studies including 755 patients (3442 person-years with 376 deaths) were eligible for meta-analysis. Mean u5-HIAA was 149.2 mg/24 h (standard deviation: 96.6) and mortality was 13.0%. The meta-regression equation showed an 11.8% (95% CI: 8.9-17.0%; I²  = 93.0%) increase in 1-year mortality for every ten-unit increase in u5-HIAA. Conclusion: Serotonin measured by its metabolite u5-HIAA is predictive of 1-year all-cause mortality in patients with NETs.

Current Treatment Strategies and Future Treatment Options for Dravet Syndrome

PURPOSE OF REVIEW

Dravet syndrome is a rare but severe genetic epilepsy that has unique treatment challenges. This is a review of current and future potential treatment options.

RECENT FINDINGS

Treatment for Dravet syndrome should encompass many aspects of the syndrome such as gait, behavior, and nutrition, as well as focus on seizure control. Many sodium channel blockers should be avoided as they are likely to exacerbate seizures. Current options for treatment include valproic acid, clobazam, stiripentol, and ketogenic diet. Testing is underway for several new treatment options with unique mechanisms of action and therapeutic targets, including the serotonin system and genetic modulation. Accurate and early diagnosis of Dravet syndrome will lead to avoidance of medications that may exacerbate seizures. Additionally, a multi-disciplinary approach and careful planning for management of episodes of status epilepticus may lead to improved outcomes. Ongoing research for novel approaches to treatment creates optimism for future improvement in outcomes.

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.

Pharmacogenomics in epilepsy

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Genetic variation can influence response to antiepileptic drug (AED) treatment through various effector processes.

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Metabolism of many AEDs is mediated by the cytochrome P450 (CYP) family; some of the CYPs have allelic variants that may affect serum AED concentrations.

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‘Precision medicine’ focuses on the identification of an underlying genetic aetiology allowing personalised therapeutic choices.

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Certain human leukocyte antigen, HLA, alleles are associated with an increased risk of idiosyncratic adverse drug reactions.

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New results are emerging from large-scale multinational efforts, likely imminently to add knowledge of value from a pharmacogenetic perspective.

There is high variability in the response to antiepileptic treatment across people with epilepsy. Genetic factors significantly contribute to such variability. Recent advances in the genetics and neurobiology of the epilepsies are establishing the basis for a new era in the treatment of epilepsy, focused on each individual and their specific epilepsy. Variation in response to antiepileptic drug treatment may arise from genetic variation in a range of gene categories, including genes affecting drug pharmacokinetics, and drug pharmacodynamics, but also genes held to actually cause the epilepsy itself.

From a purely pharmacogenetic perspective, there are few robust genetic findings with established evidence in epilepsy. Many findings are still controversial with anecdotal or less secure evidence and need further validation, e.g. variation in genes for transporter systems and antiepileptic drug targets. The increasing use of genetic sequencing and the results of large-scale collaborative projects may soon expand the established evidence.

Precision medicine treatments represent a growing area of interest, focussing on reversing or circumventing the pathophysiological effects of specific gene mutations. This could lead to a dramatic improvement of the effectiveness and safety of epilepsy treatments, by targeting the biological mechanisms responsible for epilepsy in each specific individual.

Whilst much has been written about epilepsy pharmacogenetics, there does now seem to be building momentum that promises to deliver results of use in clinic.

Drug-induced aortic valve stenosis: An under recognized entity

BACKGROUND

We have been intrigued by the observation that aortic stenosis (AS) may be associated with characteristic features of mitral drug-induced valvular heart disease (DI-VHD) in patients exposed to valvulopathic drugs, thus suggesting that beyond restrictive heart valve regurgitation, valvulopathic drugs may be involved in the pathogenesis of AS.

METHODS

Herein are reported echocardiographic features, and pathological findings encountered in a series of patients suffering from both AS (mean gradient >15mmHg) and mitral DI-VHD after valvulopathic drugs exposure. History of rheumatic fever, chest radiation therapy, systemic disease or bicuspid aortic valve disease were exclusion criteria.

RESULTS

Twenty-five (19 females, mean age 62years) patients having both AS and typical features of mitral DI-VHD were identified. Mean transaortic pressure gradient was 32+/-13mmHg. Aortic regurgitation was ≥ mild in 24 (96%) but trivial in one. Known history of aortic valve regurgitation following drug initiation prior the development of AS was previously diagnosed in 17 patients (68%). Six patients underwent aortic valve replacement and 3 both aortic and mitral valve replacement. In the 9 patients with pathology analysis, aortic valvular endocardium was markedly thickened by dense non-inflammatory fibrosis, a characteristic feature of DI-VHD.

CONCLUSION

The association between AS and typical mitral DI-VHD after valvulopathic drug exposure may not be fortuitous. Aortic regurgitation was usually associated to AS and preceded AS in most cases but may be lacking. Pathology demonstrated the potential role of valvulopathic drugs in the development of AS.

Five-year extended follow-up status of 10 patients with Dravet syndrome treated with fenfluramine

Dravet syndrome (DS) is a rare and therapy-resistant epilepsy syndrome. A retrospective analysis of add-on fenfluramine treatment in 12 patients with DS was published in 2012 and provided evidence of a meaningful long-term response. Herein we present the results of a subsequent 5-year prospective observation of this original cohort. Ten patients with a mean current age of 24 years were followed prospectively from 2010 until 2014. The mean current dose of fenfluramine was 0.27 mg/kg/day, with a mean treatment duration of 16.1 years. Seizure frequency was derived from a seizure diary. Cardiac examinations and assessments of clinical effectiveness and adverse events were performed at least annually. Three patients were seizure-free for the entire 5 years, and an additional four patients experienced seizure-free intervals of at least 2 years. Fenfluramine was generally well-tolerated. Two patients had mild (stable) valve thickening on the last echocardiography that was deemed clinically insignificant. No patient had any clinical or echocardiographic signs of pulmonary hypertension. These findings support the long-term control of convulsive seizures by low-dose fenfluramine while being well tolerated in this cohort of patients with DS. After up to 27 years of treatment, no patient has developed any clinical signs or symptoms of cardiac valvulopathy or pulmonary hypertension.

Carcinoid heart disease: current understanding and future directions

Carcinoid tumors are rare and aggressive malignancies. A multitude of vasoactive agents are central to the systemic effects of these tumors. The additional burden of cardiac dysfunction heralds a steep decline in quality of life and survival. Unfortunately, by the time carcinoid syndrome surfaces clinically, the likelihood of cardiac involvement is 50%. Although medical therapies such as somatostatin analogues may provide some symptom relief, they offer no mortality benefit. On the other hand, referral to surgery following early detection has shown increased survival. The prompt recognition of this disease is therefore of the utmost importance.

Benfluorex and Mortality: A Fresh Perspective

Benfluorex, a drug related to fenfluramine, has been sold under the trade name “Mediator” by Servier Laboratories and was introduced to the French market in 1976, licenced for the treatment of type 2 diabetes and dyslipidemia. Although the evidence that benfluorex increases the risk of mild valvular regurgitant abnormalities is convincing, it is also apparent that no data exist from which to calculate the risk of death attributable to benfluorex use. Despite this, two studies have attempted to make such estimates, the results of which have been the focus of much media attention. In this review, we attempt to provide a further assessment of the evidence base, explore the limitations of the estimates of death that have been made, and calculate the population risk of mild valvular regurgitation and hospitalisation attributable to benfluorex use. We conclude that the previously published estimates of deaths attributed to the use of this agent are unsafe, based on unfounded assumptions, and are highly likely to be inaccurate.

Study exploring depression and cardiovascular diseases amongst Arabic speaking patients living in the State of Qatar: Rationale and methodology

In Qatar, cardiovascular diseases are the leading cause of death. Studies show that depression is associated with an increased morbidity and mortality among cardiovascular patients. Thus, early detection of, and intervention for, depression among cardiovascular patients can reduce cardiovascular morbidity and mortality, and save health care costs. To date there is no study in the Gulf region exploring depression among cardiovascular patients. The goals of our three-phase research program are to (1) understand the mental health issues, specifically depression, as experienced by cardiovascular patients living in the State of Qatar; (2) identify and implement strategies that would prevent depression and assist patients to deal with depression; and (3) evaluate, facilitate, and sustain strategies that are effective at reducing depression and foster its treatment among cardiovascular patients. This paper describe phase I of the research program. Using both quantitative and qualitative research methodologies, we will investigate (1) the prevalence and severity of depression among patients who have confirmed diagnosis of cardiovascular diseases (2) how contextual factors such as social, cultural, and economic factors contribute to the risk of depression and its management among cardiovascular patients, and (3) formulate effective intervention strategies that are expected to increase awareness, prevention of and treatment for depression among cardiovascular patients, thus reducing cardiovascular diseases morbidity and mortality in Qatar.

Frequency of drug-induced valvular heart disease in patients previously exposd to benfluorex: a multicentre prospective study

AIMS

The epidemiologic link between benfluorex use and an increased global frequency of left heart valve regurgitation has been well documented. However, no data linking previous drug exposure to the frequency of diagnosis of drug-induced valvular heart disease (DI-VHD) are available. The present study was conducted to address this issue.

METHODS AND RESULTS

This echocardiography reader-blinded, controlled study conducted in 10 centres between February 2010 and February 2012 prospectively included 835 subjects previously exposed to benfluorex referred by primary care physicians for echocardiography. Based on blinded off-line analysis, echocardiography findings were classified as: (i) DI-VHD⁺ for patients with an echocardiographic diagnosis of DI-VHD, (ii) inconclusive, and (iii) DI-VHD⁻ for patients without signs of DI-VHD. Fifty-seven (6.8%) patients exposed to benfluorex were classified as DI-VHD⁺, 733 (87.8%) patients were classified as DI-VHD⁻, and 45 (5.4%) were classified as inconclusive. Mitral and aortic DI-VHD were reported in 43 patients (5.1%) and 30 (3.6%) patients, respectively. Longer duration of exposure, female gender, smoking, and lower BMI were independently associated with a diagnosis of DI-VHD. Good inter-observer reproducibility was observed for the echocardiography classification (Kappa = 0.83, P < 0.00001).

CONCLUSIONS

About 7% of patients without a history of heart valve disease previously exposed to benfluorex present echocardiography features of DI-VHD. Further studies are needed to study the natural history of DI-VHD and to identify risk factors for the development of drug-induced valve lesions.

Strategies for preventing type 2 diabetes: an update for clinicians

Diabetes is a major and growing public health challenge which threatens to overwhelm medical services in the future. Type 2 diabetes confers significant morbidity and mortality, most notably with target organ damage to the eyes, kidneys, nerves and heart. The magnitude of cardiovascular risk associated with diabetes is best illustrated by its position as a coronary heart disease risk equivalent. Complications related to neuropathy are also vast, often working in concert with vascular abnormalities and resulting in serious clinical consequences such as foot ulceration. Increased understanding of the natural history of this disorder has generated the potential to intervene and halt pathological progression before overt disease ensues, after which point management becomes increasingly challenging. The concept of prediabetes as a formal diagnosis has begun to be translated from the research setting to clinical practice, but with continually updated guidelines, varied nomenclature, emerging pharmacotherapies and an ever-changing evidence base, clinicians may be left uncertain of best practice in identifying and managing patients at the prediabetic stage. This review aims to summarize the epidemiological data, new concepts in disease pathogenesis and guideline recommendations in addition to lifestyle, pharmacological and surgical therapies targeted at stopping progression of prediabetes to diabetes. While antidiabetic medications, with newer anti-obesity medications and interventional bariatric procedures have shown some promising benefits, diet and therapeutic lifestyle change remains the mainstay of management to improve the metabolic profile of individuals with glucose dysregulation. New risk stratification tools to identify at-risk individuals, coupled with unselected population level intervention hold promise in future practice.

Validation of a population-based method to assess drug-induced alterations in the QT interval: a self-controlled crossover study

PURPOSE

The purpose of this study was to ascertain, in the context of an integrated health care delivery system, the association between a comprehensive list of drugs known to have potential QT liability and QT prolongation or shortening.

METHODS

By using a self-controlled crossover study with 59 467 subjects, we ascertained intra-individual change in log-linear regression-corrected QT (QTcreg ) during the period between 1995 and mid-2008 for 90 drugs while adjusting for age, gender, race/ethnicity, comorbid conditions, number of electrocardiograms (ECGs), and time between pre-ECG and post-ECG. The proportion of users of each drug-developing incident long QT was also estimated.

RESULTS

Two drugs (nicardipine and levalbuterol) had no statistically significant intra-individual QTcreg shortening effects, 10 drugs had no statistically significant prolonging effect, and 78 (87%) of the drugs had statistically significant intra-individual mean QTcreg lengthening effects, ranging from 7.6 ms for aripiprazole to 25.2 ms for amiodarone. Three drugs were associated with mean QTcreg prolongation of 20 ms or greater: amiodarone (antiarrhythmic), terfenadine (antihistaminic), and quinidine (antiarrhythmic); whereas 11 drugs were associated with mean QTcreg prolongation of 15 ms or greater but less than 20 ms: trimipramine (tricyclic antidepressant), clomipramine (tricyclic antidepressant), disopyramide (antiarrhythmic), chlorpromazine (antipsychotic), sotalol (beta blocker), itraconazole (antifungal), phenylpropanolamine (decongestant/anorectic), fenfluramine (appetite suppressant), midodrine (antihypotensive), digoxin (cardiac glycoside/antiarrhythmic), and procainamide (antiarrhythmic).

CONCLUSIONS

QT prolonging effects were common and varied in strength. Our results lend support to past Food and Drug Administration regulatory actions and support the role for ongoing surveillance of drug-induced QT prolongation.

Cardiac valve involvement in systemic diseases: a review

Increasing age and new trends of mixed populations have newly aroused interest in valvular heart disease in the developed countries still in need of new clinical insights. In the clinical setting of systemic diseases, the proper assessment of cardiovascular abnormalities may be challenging, and the characterization of valvular involvement might help to recognize the underlying disease and cardiac sequelae. Prompt identification of valvular lesions may, therefore, also be useful for differential diagnosis. This article reviews the cardiac involvement in systemic diseases from etiology and background definition to echocardiographic assessment and clinical interpretation.

Increased risk of left heart valve regurgitation associated with benfluorex use in patients with diabetes mellitus: a multicenter study

BACKGROUND

Benfluorex was withdrawn from European markets in June 2010 after reports of an association with heart valve lesions. The link between benfluorex and valve regurgitations was based on small observational studies and retrospective estimations. We therefore designed an echocardiography-based multicenter study to compare the frequency of left heart valve regurgitations in diabetic patients exposed to benfluorex for at least 3 months and in diabetic control subjects never exposed to the drug.

METHODS AND RESULTS

This reader-blinded, controlled study conducted in 10 centers in France between February 2010 and September 2011 prospectively included 376 diabetic subjects previously exposed to benfluorex who were referred by primary care physicians for echocardiography and 376 diabetic control subjects. Through the use of propensity scores, 293 patients and 293 control subjects were matched for age, sex, body mass index, smoking, dyslipidemia, hypertension, and coronary artery disease. The main outcome measure was the frequency of mild or greater left heart valve regurgitations. In the matched sample, the frequency and relative risk (odds ratio) of mild or greater left heart valve regurgitations were significantly increased in benfluorex patients compared with control subjects: 31.0% versus 12.9% (odds ratio, 3.55; 95% confidence interval, 2.03-6.21) for aortic and/or mitral regurgitation, 19.8% versus 4.7% (odds ratio, 5.29; 95% confidence interval, 2.46-11.4) for aortic regurgitation, and 19.4% versus 9.6% (odds ratio, 2.38; 95% confidence interval, 1.27-4.45) for mitral regurgitation.

CONCLUSIONS

Our results indicate that the use of benfluorex is associated with a significant increase in the frequency of left heart valve regurgitations in diabetic patients. The natural history of benfluorex-induced valve abnormalities needs further research.

Fenfluramine-induced gene dysregulation in human pulmonary artery smooth muscle and endothelial cells

Fenfluramine is prescribed either alone or in combination with phentermine as part of Fen-Phen, an anti-obesity medication. Fenfluramine was withdrawn from the US market in 1997 due to reports of heart valvular disease, pulmonary arterial hypertension, and cardiac fibrosis. Particularly, idiopathic pulmonary arterial hypertension (IPAH), previously referred to as primary pulmonary hypertension (PPH), was found to be associated with the use of Fen-Phen, fenfluramine, and fenfluramine derivatives. The underlying mechanism of fenfluramine-associated pulmonary hypertension is still largely unknown. We reasoned that investigating drug-induced gene dysregulation would enhance our understanding of the fenfluramine-associated pathogenic mechanism of IPAH. Whole-genome gene expression profiles in fenfluramine-treated human pulmonary artery smooth muscle (PASMC) and endothelial (PAEC) cells (isolated from normal subjects) were compared with baseline expression in untreated cells. Fenfluramine treatment caused dysregulation in a substantial number of genes involved in a variety of pathways and biological processes. In addition to several common pathways and biological processes such as "MAPK signaling pathway," "inflammation response," and "calcium signaling pathway" shared between both cell types, pathways and biological processes such as "blood circulation," "muscle system process," and "immune response" were enriched among the dysregulated genes in PASMC. Pathways and biological processes such as those related to cell cycle, however, were enriched among the dysregulated genes in PAEC, indicating that fenfluramine could affect unique pathways (or differentially) in different types of pulmonary artery cells. While awaiting validation in a larger cohort, these results strongly suggested that fenfluramine could induce significant dysregulation of genes in multiple biological processes and pathways critical for normal pulmonary vascular functions and structure. The transcriptional and posttranscriptional changes in these genes may, therefore, contribute to the pathogenesis of fenfluramine-associated IPAH.

Echocardiographic evidence for valvular toxicity of benfluorex: a double-blind randomised trial in patients with type 2 diabetes mellitus

Objectives

REGULATE trial was designed to compare the efficacy and safety of benfluorex versus pioglitazone in type 2 diabetes mellitus (DM) patients.

Methods

Double-blind, parallel-group, international, randomised, non-inferiority trial. More than half of the 196 participating centres were primary care centres. Patients eligible had type 2 DM uncontrolled on sulfonylurea. 846 were randomised. They received study treatment for 1 year. 423 patients were allocated to benfluorex (150 to 450 mg/day) and 423 were allocated to pioglitazone (30 to 45 mg/day). Primary efficacy criterion was HbA_1c. Safety assessment included blinded echocardiographic evaluation of cardiac and valvular status.

Results

At baseline, patients were 59.1±10.5 years old with HbA1c 8.3±0.8%, and DM duration 7.1±6.0 years. During the study, mean HbA1c significantly decreased in both groups (benfluorex: from 8.30±0.80 to 7.77±1.31 versus pioglitazone: from 8.30±0.80 to 7.45±1.30%). The last HbA1c value was significantly lower with pioglitazone than with benfluorex (p<0.001) and non-inferiority of benfluorex was not confirmed (p = 0.19). Among the 615 patients with assessable paired echocardiography (310 benfluorex, 305 pioglitazone), 314 (51%) had at least one morphological valvular abnormality and 515 (84%) at least one functional valvular abnormality at baseline. Emergent morphological abnormalities occurred in 8 patients with benfluorex versus 4 with pioglitazone (OR 1.99), 95% CI (0.59 to 6.69). Emergent regurgitation (new or increased by one grade or more) occurred more frequently with benfluorex (82 patients, 27%) than with pioglitazone (33 patients, 11%) (OR 2.97), 95% CI (1.91 to 4.63) and were mainly rated grade 1; grade 2 (mild) was detected in 2 patients with benfluorex and 3 with pioglitazone. There was no moderate or severe regurgitation.

Conclusion

After 1 year of exposure, our results show a 2.97 fold increase in the incidence of valvular regurgitation with benfluorex and provide evidence for the valvular toxicity of this drug.

Trial registration

www.controlled-trials.com ISRCTN 27354239. isrctn27354239

Successful use of fenfluramine as an add-on treatment for Dravet syndrome

PURPOSE

Despite the development of new antiepileptic drugs, Dravet syndrome frequently remains therapy resistant and is a catastrophic epilepsy syndrome. Fenfluramine is an amphetamine-like drug that has been used in the past as a part of antiobesity treatments. Because of the possible cardiac adverse effects (valve thickening, pulmonary hypertension) associated with use of fenfluramine, it was withdrawn from the market in 2001. In Belgium, a Royal Decree permitted examination of the potential anticonvulsive effects of fenfluramine in a clinical trial consisting of a small group of patients diagnosed with Dravet syndrome.

METHODS

Herein, we report 12 patients, 7 female and 5 male, with a genetically proven (11 of 12) diagnosis of Dravet syndrome who received fenfluramine as add-on therapy.

KEY FINDINGS

Their ages at their last evaluation ranged from 3-35 years. The mean dosage of fenfluramine was 0.34 (0.12-0.90) mg/kg/day. Exposure duration to fenfluramine ranged from 1-19 years. Seven of the patients who were still receiving the fenfluramine treatment at the time of the last visit had been seizure-free for at least 1 year. In total, patients had been seizure-free for a mean of 6 (1-19) years. In seven patients, the fenfluramine treatment was interrupted once during the follow-up; seizures reappeared in three of the seizure-free patients. Subsequent reintroduction of fenfluramine controlled the seizures in these three patients again. Only two patients exhibited a mild thickening of one or two cardiac valves without clinical significance.

SIGNIFICANCE

Compared with a recent long-term follow-up series in which a maximum of 16% of patients with Dravet syndrome were seizure-free, our result of 70% of patients with Dravet syndrome remaining seizure-free is noteworthy. Given the limitations of this observational study, a larger prospective study should be undertaken to confirm these promising results.

Pulmonary arterial hypertension and benfluorex: 5 case reports

Benfluorex, an amphetamine derivative, was marketed as an adjunctive drug for patients with hypertriglyceridemia or diabetes with overweight. We describe here 5 cases of pulmonary arterial hypertension (PAH) associated to a treatment with this drug and notified to the Midi-Pyrénées Pharmacovigilance Centre. All cases are women, exposed to benfluorex during at least 3 years. In most of cases, benfluorex was used off-licence, for overweight.

Valvular heart disease associated with benfluorex therapy: results from the French multicentre registry

AIMS

The aim of this paper is to report clinical characteristics, consequences, echocardiographic features, and pathological findings encountered in patients suffering from valvular disease associated with benfluorex exposure in a multicentre French registry.

METHODS AND RESULTS

Forty patients suffering from unexplained restrictive valvular disease with a previous exposition to benfluorex, a fenfluramine derivative, were identified from eight French university hospitals. Patients were mostly women (87.5%) with a mean age of 57 ± 9 years and high body mass index of 30 ± 7 kg/m²; 37.5% of them presented with severe heart failure symptoms (NYHA class III and IV). Benfluorex mean daily dose was 415 ± 131 mg with total therapy duration of 72 ± 53 months. Resulting cumulative dose was 910 ± 675 g. Common echocardiographic findings were leaflets and sub-valvular apparatus thickening and retraction. Aortic and mitral valve regurgitations resulting from leaflets loss of coaptation were the most frequent findings (87.5 and 82.5%) and were severe in 29 patients (72.5%). Multiple valve involvements were present in 31 cases (77.5%). Pulmonary arterial hypertension was identified in 20 cases (50%). Histopathological examination demonstrated abundant extra cellular matrix encasing the leaflets without modification of valve architecture. Fifteen patients (37.5%) underwent valvular surgery.

CONCLUSION

Benfluorex-related valvulopathy shares numerous characteristics with other drug-induced valvular disease. Clinical consequences may be serious with severe heart failure symptoms that may lead to surgical treatment.

Drug-induced valvulopathy: an update

Drug-induced valvulopathy is a serious liability for certain compound classes in development and for some marketed drugs intended for human use. Reports of valvulopathy led to the withdrawal of fenfluramines (anorexigens) and pergolide (antiparkinson drug) from the United States market in 1997 and 2007, respectively. The mechanism responsible for the pathogenesis of valvulopathy by these drugs is likely a result of an "off-target" effect via activation of 5-hydroxytryptamine (5-HT) 2B receptor (5-HT2BR) expressed on heart valve leaflets. Microscopically, the affected valve leaflets showed plaques of proliferative myofibroblasts in an abundant extracellular matrix, composed primarily of glycosaminoglycans. However, the valvular effects caused by fenfluramines and pergolide were not initially predicted from routine preclinical toxicity studies, and to date there are no specific validated animal models or preclinical/toxicologic screens to accurately predict drug-induced valvulopathy. This review covers the structure and function of heart valves and highlights major advances toward understanding the 5-HT2BR-mediated pathogenesis of the lesion and subsequently, development of appropriate animal models using novel techniques/experiments, use of functional screens against 5-HT2BR, and more consistent sampling and pathologic evaluation of valves in preclinical studies that will aid in avoidance of future drug-induced valvulopathy in humans.

Benfluorex and unexplained valvular heart disease: a case-control study

Background

Recent case reports suggest that benfluorex, a fenfluramine derivative used in the management of overweight diabetic patients and dyslipidemia, is associated with cardiac valve regurgitation.

Methods

We conducted a case-control study. Eligible patients were those admitted in the cardiology or the cardiac surgery units of our hospital between January, 1^st 2003 and June 30^th 2009, with mitral insufficiency diagnostic codes (ICD-10 I340 and I051). Patients with either a primary cause (degenerative, known rheumatic heart disease, infectious endocarditis, congenital, radiation-induced valvular disease, associated connective and/or vasculitis disease, trauma, tumor) or a secondary (functional) cause were considered as having an “explained” mitral regurgitation. Other patients were considered as having an “unexplained” mitral regurgitation and were included as cases. For each case, two controls were matched for gender and for the closest date of birth, among a list of patients with an “explained” mitral regurgitation. Drug exposures were assessed blindly regarding the case or control status, through contacts with patients, their family and/or their physicians.

Results

Out of the 682 eligible patients, 27 cases and 54 matched controls were identified. The use of benfluorex was reported in 22 patients: 19 of the 27 cases, versus 3 of the 54 controls, odds-ratio 17.1 (3.5 to 83), adjusted for body mass index, diabetes and dexfenfluramine use.

Conclusion

The use of benfluorex is associated with unexplained mitral regurgitation.

Serotonergic drugs and valvular heart disease

BACKGROUND

The serotonin (5-HT) releasers (+/-)-fenfluramine and (+)-fenfluramine were withdrawn from clinical use owing to increased risk of valvular heart disease. One prevailing hypothesis (i.e., the '5-HT hypothesis') suggests that fenfluramine-induced increases in plasma 5-HT underlie the disease.

OBJECTIVE

Here, we critically evaluate the possible mechanisms responsible for fenfluramine-associated valve disease.

METHODS

Findings from in vitro and in vivo experiments performed in our laboratory are reviewed. The data are integrated with existing literature to address the validity of the 5-HT hypothesis and suggest alternative explanations.

CONCLUSIONS

The overwhelming majority of evidence refutes the 5-HT hypothesis. A more likely cause of fenfluramine-induced valvulopathy is activation of 5-HT(2B) receptors on heart valves by the metabolite norfenfluramine. Future serotonergic medications should be designed to lack 5-HT(2B) agonist activity.