Pharmacology of flibanserin

Flibanserin conquers murine depressive pseudodementia by amending HPA axis, maladaptive inflammation and AKT/GSK/STAT/BDNF trajectory: Center-staging of the serotonergic/adrenergic circuitry

Depressive pseudodementia (DPD) is a debilitating cognitive dysfunction that accompanies major and/or frequent depressive attacks. DPD has gained significant research attention owing to its negative effects on the patients' quality of life and productivity. This study tested the procognitive potential of Flibanserin (FBN), the serotonin (5HT) receptor modulator, against propranolol (PRP), as β/5HT1A receptors blocker. Serving this purpose, female Wistar Albino rats were subjected to chronic unpredictable stress (CUS) and subsequently treated with FBN only (3 mg/kg/day, p.o), PRP only (10 mg/kg/day, p.o), or PRP followed by FBN, using the same doses. FBN ameliorated the behavioral/cognitive alterations and calmed the hypothalamic-pituitary-adrenal (HPA) axis storm by reducing the levels of stress-related hormones, viz, corticotropin-releasing hormone (CRH), adrenocorticotropic hormone (ACTH), corticosterone (CORT) parallel to epinephrine (EPI) hyperstimulation. The maladaptive inflammatory response, comprising of interleukin (IL)-1β/6, and tumor necrosis factor (TNF)-α, was consequently blunted. This was contemporaneous to the partial restoration of the protein kinase-B (AKT)/glycogen synthase kinase (GSK)3β/signal transducer and activator of transcription (STAT)-3 survival trajectory and the reinstatement of the levels of brain derived neurotrophic factor (BDNF). Microscopically, FBN repaired the hippocampal architecture and lessened CD68/GFAP immunoreactivity. Pre-administration of PRP partially abolished FBN effect along the estimated parameters, except for 5HT2A receptor expression and epinephrine level, to prove 5HT1A receptor as a fulcrum initiator of the investigated pathway, while its sole administration worsened the underlying condition. Ultimately, these findings highlight the immense procognitive potential of FBN, offering a new paradigm for halting DPD advancement via synchronizing adrenergic/serotonergic circuitry.

Synthetic Approaches to Piperazine-Containing Drugs Approved by FDA in the Period of 2011-2023

The piperazine moiety is often found in drugs or in bioactive molecules. This widespread presence is due to different possible roles depending on the position in the molecule and on the therapeutic class, but it also depends on the chemical reactivity of piperazine-based synthons, which facilitate its insertion into the molecule. In this paper, we take into consideration the piperazine-containing drugs approved by the Food and Drug Administration between January 2011 and June 2023, and the synthetic methodologies used to prepare the compounds in the discovery and process chemistry are reviewed.

Structure, function and drug discovery of GPCR signaling

G protein-coupled receptors (GPCRs) are versatile and vital proteins involved in a wide array of physiological processes and responses, such as sensory perception (e.g., vision, taste, and smell), immune response, hormone regulation, and neurotransmission. Their diverse and essential roles in the body make them a significant focus for pharmaceutical research and drug development. Currently, approximately 35% of marketed drugs directly target GPCRs, underscoring their prominence as therapeutic targets. Recent advances in structural biology have substantially deepened our understanding of GPCR activation mechanisms and interactions with G-protein and arrestin signaling pathways. This review offers an in-depth exploration of both traditional and recent methods in GPCR structure analysis. It presents structure-based insights into ligand recognition and receptor activation mechanisms and delves deeper into the mechanisms of canonical and noncanonical signaling pathways downstream of GPCRs. Furthermore, it highlights recent advancements in GPCR-related drug discovery and development. Particular emphasis is placed on GPCR selective drugs, allosteric and biased signaling, polyphamarcology, and antibody drugs. Our goal is to provide researchers with a thorough and updated understanding of GPCR structure determination, signaling pathway investigation, and drug development. This foundation aims to propel forward-thinking therapeutic approaches that target GPCRs, drawing upon the latest insights into GPCR ligand selectivity, activation, and biased signaling mechanisms.

A systematic UHPLC-Q-TOF-MS/MS based analytical approach for characterization of flibanserin metabolites and establishment of biotransformation pathway

A systematic metabolite profiling approach has paramount importance in detecting, identifying, and characterizing drug metabolites. Till date, there is no report published on the comprehensive metabolic fate of flibanserin (FLB). In this study, the structure of entire potential metabolites of FLB has been elucidated by execution of in silico tool and high resolution mass spectrometry based metabolite profiling strategy employing data-dependent and data-independent approaches. In vitro metabolism profile was investigated after incubating FLB with liver microsomes (rat and human) and S9 fractions in presence of their respective co-factors. In vivo metabolites were identified from rat plasma, urine, feces, and brain tissue samples. An efficient extraction technique was developed that made it possible to identify the metabolites generated even in extremely low concentrations. Extraction was carried out by precipitating protein and thereafter solid-phase extraction to enrich their concentration in the sample before analysis. Fourteen new metabolites have been identified and characterized. Most of the metabolites of FLB were generated due to hydrolysis and oxidation followed by glucuronide, sulfate, and methyl conjugation. Additionally, a spiking study was employed to confirm the presence of N-oxide metabolite in human liver S9 fraction and rat urine samples. Moreover, we have established the probable biotransformation pathway of FLB and successfully analyzed the toxicity potential of the metabolites using Pro Tox-II software.

Efficient Amination of Activated and Non-Activated C(sp3 )-H Bonds with a Simple Iron-Phenanthroline Catalyst

A readily available catalyst consisting of iron dichloride in combination with 1,10-phenanthroline catalyzes the ring-closing C-H amination of N-benzoyloxyurea to form imidazolidin-2-ones in high yields. The C-H amination reaction is very general and applicable to benzylic, allylic, propargylic, and completely non-activated aliphatic C(sp3 )-H bonds, and it also works for C(sp2 )-H bonds. The surprisingly simple method can be performed under open flask conditions.

International Union of Basic and Clinical Pharmacology. CX. Classification of Receptors for 5-hydroxytryptamine; Pharmacology and Function

5-HT receptors expressed throughout the human body are targets for established therapeutics and various drugs in development. Their diversity of structure and function reflects the important role 5-HT receptors play in physiologic and pathophysiological processes. The present review offers a framework for the official receptor nomenclature and a detailed understanding of each of the 14 5-HT receptor subtypes, their roles in the systems of the body, and, where appropriate, the (potential) utility of therapeutics targeting these receptors. SIGNIFICANCE STATEMENT: This review provides a comprehensive account of the classification and function of 5-hydroxytryptamine receptors, including how they are targeted for therapeutic benefit.

Psychological Treatment of Low Sexual Desire in Women: Protocol for a Randomized, Waitlist-Controlled Trial of Internet-Based Cognitive Behavioral and Mindfulness-Based Treatments

BACKGROUND

Psychological therapies are effective treatments for hypoactive sexual desire dysfunction (HSDD; formerly hypoactive sexual desire disorder), a common sexual dysfunction among women. Access to evidence-based treatments, however, remains difficult. Internet-based interventions are effective for a variety of psychological disorders and may be a promising means to close the treatment gap for HSDD.

OBJECTIVE

This article describes the treatment protocol and study design of a randomized controlled trial, aiming to study the efficacy of cognitive behavioral and mindfulness-based interventions delivered via the internet for women with HSDD to a waitlist control group. Outcomes are sexual desire (primary) and sexual distress (secondary). Additional variables (eg, depression, mindfulness, rumination) will be assessed as potential moderators or mediators of treatment success.

METHODS

A cognitive behavioral and a mindfulness-based self-help intervention for HSDD will be provided online. Overall, 266 women with HSDD will be recruited and assigned either to one of the intervention groups, or to a waitlist control group (2:2:1). Outcome data will be assessed at baseline, at 12 weeks, and at 6 and 12 months after randomization. Intention-to-treat and completer analyses will be conducted.

RESULTS

We expect improvements in sexual desire and sexuality-related distress in both intervention groups compared to the waitlist control. Recruitment has begun in January 2019 and is expected to be completed in August 2021. Results will be published in 2022.

CONCLUSIONS

This study aims to contribute to the improvement and dissemination of psychological treatments for women with HSDD and to clarify whether cognitive behavioral and/or mindfulness-based treatments for HSDD are feasible and effective when delivered via the internet.

TRIAL REGISTRATION

ClinicalTrials.gov NCT03780751; https://clinicaltrials.gov/ct2/show/NCT03780751.

INTERNATIONAL REGISTERED REPORT IDENTIFIER (IRRID)

DERR1-10.2196/20326.

Drug-Drug Interactions (DDIs) in Psychiatric Practice, Part 8: Relative Receptor Binding Affinity as a Way of Understanding the Differential Pharmacology of Currently Available Antidepressants

This column is the eighth in a series exploring drug-drug interactions (DDIs) with a special emphasis on psychiatric medications. The first 3 columns in this DDI series discussed why patients being treated with psychiatric medications are at increased risk for taking multiple medications and thus experiencing DDIs, how to recognize such DDIs, strategies for avoiding and/or minimizing adverse outcomes from such DDIs, and pharmacokinetic considerations concerning DDIs in psychiatric practice. The fourth and fifth columns in this series presented a pair of parallel tables, one of which outlined the primary, known mechanism(s) of action of all commonly used psychiatric medications and one of which summarized major types of pharmacodynamic DDIs based on mechanism of action. Clinicians can use these 2 tables together to predict pharmacodynamically mediated DDIs. The sixth column discussed key pharmacodynamic interactions involving ethanol, opioids, and monoamine oxidase inhibitors. That column focused particularly on hypertensive crises and serotonin syndrome with monoamine oxidase inhibitors and also DDIs involving psychiatric medications with adverse effects on the cardiovascular system and on the central nervous system. The seventh column presented the concept of relative receptor binding and included a table summarizing the relative receptor binding affinity of antipsychotics including all of the newer agents as well as some of the older agents such as haloperidol. This eighth column in this series presents a parallel table to the one in the seventh column summarizing the relative receptor binding affinity of currently available antidepressants. The overall goal of this series of columns is to present a simple way of conceptualizing neuropsychiatric medications in terms of their pharmacodynamics and pharmacokinetics to allow prescribers to take these facts into consideration when they need to use ≥2 drugs in combination to optimally treat a patient.

Evaluation of safety for flibanserin

Introduction: Hypoactive sexual desire disorder (HSDD) is the most prevalent sexual dysfunction in women, previously managed with off-label therapies. Indicated for premenopausal women, flibanserin is the first FDA-approved medication to treat HSDD.Areas covered: This review summarizes flibanserin's pharmacokinetics, proposed mechanism of action, and safety data in clinical trials with a focus on sedation- and hypotension-related adverse events, and drug interactions with alcohol and antidepressants. Sources included peer-reviewed publications and internal data from the manufacturer.Expert opinion: Flibanserin is a well-tolerated and effective treatment that decreases distress and restores sexual desire to a level that is normative for the individual patient with HSDD. Simplification of a risk mitigation program for flibanserin in the US is likely to increase the number of prescribing clinicians if accompanied with educational efforts to clarify flibanserin's risk-benefit profile. As flibanserin is dosed daily and may be used for a decade or more in the typical premenopausal patient, long-term pharmacovigilance data will be essential. Over time, HSDD will be treated by more nonspecialist health care professionals and flibanserin will likely become established as a significant treatment option along with other medications approved for this indication in the context of a holistic biopsychosocial treatment paradigm.

Safety and Tolerability of Evening Ethanol Consumption and Bedtime Administration of Flibanserin in Healthy Premenopausal Female Subjects

INTRODUCTION

Flibanserin, a treatment for hypoactive sexual desire disorder, carries warnings for increased risk of severe hypotension and syncope when used with alcohol. However, these warnings are not informed by studies that used flibanserin's recommended bedtime dosing because previous alcohol studies assessed flibanserin's safety during the day.

AIM

The aim of this study was to assess the effects of ethanol in a real-world context in premenopausal women taking flibanserin at bedtime.

METHODS

In a randomized, placebo-controlled, double-blind study, 24 healthy premenopausal women (mean age = 34.5 ± 9.9 years; mean body mass index = 25.2 ± 3.4 kg/m2) were dosed with flibanserin or placebo for 3 days to achieve steady-state plasma levels. In a clinical research unit, subjects (n = 22) were provided 2 units of wine (150 mL/unit; 12% ethanol content) or a nonalcoholic beverage with a standardized 3-course evening meal. Flibanserin 100 mg or placebo was administered at bedtime 2.5 hours after the end of the evening meal. On a separate day, subjects were provided the alternative beverage (± alcohol) with the same evening meal and dosed with the same treatment (flibanserin or placebo) at bedtime. After a 5-day washout period, subjects crossed over to the other treatment arm and the protocol was repeated.

MAIN OUTCOME MEASURE

Adverse events (AEs) and vital signs were monitored.

RESULTS

In the absence of ethanol, headaches and hypotension were the only AEs that occurred in ≥2 subjects after flibanserin dosing (placebo corrected rates were 17.4% and 8.7%, respectively). After ethanol consumption, the rate of hypotension after flibanserin dosing was no greater than with flibanserin or placebo after nonalcoholic beverage consumption. There were no instances of orthostatic hypotension or syncope and no serious AEs or AEs leading to study discontinuation.

CONCLUSION

Flibanserin dosed at bedtime after moderate amounts of alcohol with an evening meal was well-tolerated with no evidence of clinically significant hypotension or syncope. Millheiser L, Clayton AH, Parish SJ, et al. Safety and Tolerability of Evening Ethanol Consumption and Bedtime Administration of Flibanserin in Healthy Premenopausal Female Subjects. Sex Med 2019;7:418-424.

Safety of Flibanserin in Women Treated With Antidepressants: A Randomized, Placebo-Controlled Study

BACKGROUND

Depression is often associated with sexual dysfunction, and pharmacologic treatment for hypoactive sexual desire disorder can be considered in women receiving treatment for depression.

AIM

To evaluate the safety of flibanserin in women treated for depression with selective serotonin reuptake inhibitors or serotonin and norepinephrine reuptake inhibitors.

METHODS

In this double-blinded, randomized, placebo-controlled trial, women with remitted or mild depression treated with selective serotonin reuptake inhibitors or serotonin and norepinephrine reuptake inhibitors who were not postmenopausal and were experiencing symptoms of hypoactive sexual desire disorder (ie, decreased sexual desire and related distress) received flibanserin 50 mg at bedtime (qhs) for 2 weeks and up-titrated to 100 mg qhs, flibanserin 100 mg qhs for the entire treatment period, or placebo for up to 12 weeks.

OUTCOMES

Safety assessment included adverse events and symptoms of depression and anxiety.

RESULTS

73 patients were randomly assigned to flibanserin (both dose groups combined) and 38 to placebo. The sponsor terminated the study early at discontinuation of the development of flibanserin. Treatment duration was at least 8 weeks for 84.9% and 94.7% of patients in the flibanserin and placebo groups, respectively. The most common adverse events (incidence ≥ 2% in the flibanserin group and higher than that in the placebo group) included dry mouth (5.5% for flibanserin vs 2.6% for placebo), insomnia (5.5% vs 2.6%), back pain (4.1% vs 2.6%), and dizziness (4.1% vs 0.0%). There were no serious adverse events and no instances of suicidal ideation or behavior. The proportions of patients with symptom worsening in the flibanserin and placebo groups, respectively, were 6.9% and 21.6% for depression and 1.4% and 2.7% for anxiety. Remission of depression at study end point, as measured by the Quick Inventory of Depressive Symptomatology-Self Report, was experienced by 19.4% of flibanserin-treated patients and 10.8% of patients receiving placebo; remission of anxiety based on the Beck Anxiety Inventory was noted in 16.4% and 2.7% of patients, respectively.

CLINICAL IMPLICATIONS

The results of this study support the safety of flibanserin in premenopausal women being treated with a serotonergic antidepressant. No increased risks were observed when adding flibanserin to a stable selective serotonin reuptake inhibitor or serotonin and norepinephrine reuptake inhibitor treatment regimen.

STRENGTHS AND LIMITATIONS

This was a well-designed, randomized, placebo-controlled trial. The primary limitation was the early study discontinuation by the sponsor, which decreased the sample size and duration of treatment.

CONCLUSION

In this small trial, flibanserin 100 mg qhs was generally safe and well tolerated in premenopausal women with mild or remitted depression taking a serotonergic antidepressant. Clayton AH, Croft HA, Yuan J, et al. Safety of Flibanserin in Women Treated With Antidepressants: A Randomized, Placebo-Controlled Study. J Sex Med 2018;15:43-51.

Effects of Timing of Flibanserin Administration Relative to Alcohol Intake in Healthy Premenopausal Women: A Randomized, Double-Blind, Crossover Study

INTRODUCTION

Flibanserin is approved in the United States and Canada for the treatment of acquired, generalized, hypoactive sexual desire disorder in premenopausal women. Sedation-related side effects are among the most prevalent adverse events. Although infrequent, hypotension and syncope remain safety concerns because of possible interaction of flibanserin with alcohol.

AIM

To evaluate the impact of the timing of alcohol consumption on flibanserin safety and tolerability.

METHODS

In this single-center, randomized, double-blind, placebo-controlled, 4-treatment crossover study, 64 healthy premenopausal women (mean age 32.5 ± 8.7 years; range 20‒52 years) received once-daily flibanserin 100 mg or placebo during each of two 10-day treatment periods. Study medication was administered on days 1-3 to achieve steady state. On days 4, 6, 8, and 10, after a standard breakfast, participants consumed 0.4 g/kg ethanol (approximately equivalent to two 5-oz glasses of wine) administered with orange juice 2, 4, or 6 hours before taking study medication or orange juice alone (no ethanol) 2 hours before taking study medication.

OUTCOMES

The primary endpoint was percentage of participants experiencing syncope or orthostatic hypotension-associated adverse events requiring medical intervention. Secondary endpoints included the incidence of hypotension, the incidence of orthostatic hypotension, and rates of adverse events of special interest (syncope, orthostatic hypotension, dizziness, and somnolence).

RESULTS

1 participant experienced a primary endpoint event (syncope) during treatment with placebo taken 4 hours after ethanol consumption. Within each ethanol dose-timing treatment, there were no statistically significant differences for flibanserin compared with placebo. Rates of hypotension were 53.3-66.7% after flibanserin dosing and 57.4-63.3% after placebo dosing. Rates for orthostatic hypotension were 0.0-5.0% after flibanserin dosing and 1.7-6.6% after placebo dosing.

CLINICAL IMPLICATIONS

Ethanol interaction with flibanserin was not observed in this study.

STRENGTHS & LIMITATIONS

This study provides information regarding the use of flibanserin after the consumption of moderate amounts of ethanol (0.4 g/kg). However, daytime administration of flibanserin is not consistent with the drug's indicated bedtime dosing.

CONCLUSION

Flibanserin, at steady state taken 2, 4, or 6 hours after 0.4 g/kg of ethanol intake did not increase the incidence of hypotension, orthostatic hypotension, or syncope compared with either flibanserin alone or ethanol alone. Simon JA, Clayton AH, Kingsberg SA, et al. Effects of Timing of Flibanserin Administration Relative to Alcohol Intake in Healthy Premenopausal Women: A Randomized, Double-Blind, Crossover Study. J Sex Med 2019;16:1779-1786.

A rapid and sensitive UPLC-MS/MS method for the determination of flibanserin in rat plasma: application to a pharmacokinetic study

Background

In this work, we aim to develop and validate a fast, simple, and sensitive method for the quantitative determination of flibanserin and the exploration of its pharmacokinetics.

Methods

Ultra-performance liquid chromatography-tandem mass spectrometry (UHPLC-MS/MS) was the method of choice for this investigation and carbamazepine was selected as an internal standard (IS). The plasma samples were processed by one-step protein precipitation using acetonitrile. The highly selective chromatographic separation of flibanserin and carbamazepine (IS) was realised using an Agilent RRHD Eclipse Plus C18 (2.1 × 50 mm, 1.8 µ) column with a gradient mobile phase consisting of 0.1% formic acid in water and acetonitrile. The analytes were detected using positive-ion electrospray ionization mass spectrometry via multiple reaction monitoring (MRM). The target fragment ions were m/z 391.3 → 161.3 for flibanserin and m/z 237.1 → 194 for carbamazepine (IS). The method was validated by linear calibration plots over the range of 100-120,000 ng/mL for flibanserin (R² = 0.999) in rat plasma.

Results

The extraction recovery of flibanserin was in the range of 91.5-95.8%. The determined inter- and intra-day precision was below 12.0%, and the accuracy was from - 6.6 to 12.0%. No obvious matrix effect and astaticism was observed for flibanserin. The target analytes were long-lasting and stable in rat plasma for 12 h at room temperature, 48 h at 4 °C, 30 days at - 20 °C, as well as after three freeze-thaw cycles (from - 20 °C to room temperature). The proposed method has been fully validated and successfully applied to the pharmacokinetic study of flibanserin.

The human endogenous metabolome as a pharmacology baseline for drug discovery

We have limited understanding of the variation in in vitro affinities of drugs for their targets. An analysis of a highly curated set of 815 interactions between 566 drugs and 129 primary targets reveals that 71% of drug-target affinities have values above that of the corresponding endogenous ligand, 96% of them fitting within a range of two orders of magnitude. Our findings suggest that the evolutionary optimised affinity of endogenous ligands for their native proteins can serve as a baseline for the primary pharmacology of drugs. We show that the degree of off-target selectivity and safety risks of drugs derived from their secondary pharmacology depend very much on that baseline. Thus, we propose a new approach for estimating safety margins.

Weight Loss in Women Taking Flibanserin for Hypoactive Sexual Desire Disorder (HSDD): Insights Into Potential Mechanisms

INTRODUCTION

Flibanserin, a multifunctional serotonin receptor agonist and antagonist, is currently approved in the United States and Canada for the treatment of acquired, generalized hypoactive sexual desire disorder (HSDD) in premenopausal women. A post hoc analysis of HSDD clinical trial data found that flibanserin treatment was associated with statistically significant weight loss relative to placebo, even though study patients were not selected for being overweight/obese and were provided no expectation for weight reduction or interventions intended to promote weight loss.

AIM

To understand possible mechanisms by which flibanserin may produce weight loss.

METHODS

A literature review was performed using Medline database for relevant publications on the mechanisms of action by which flibanserin may provide weight loss and the links between sexual function and weight management.

MAIN OUTCOME MEASURES

Examination of (i) biopsychosocial factors regulating sexual desire, food intake, and weight regulation; (ii) clinical pharmacology of flibanserin; (iii) neurobiology of brain reward circuitry; and (iv) identification of possible mechanisms common to flibanserin and weight loss.

RESULTS

Based on flibanserin clinical trial data, there was no consistent correlation between weight loss and improvement in sexual function, as assessed by HSDD outcome measures. Nausea, a common adverse event associated with flibanserin use, also did not appear to be a contributing factor to weight loss. Hypothetical links between flibanserin treatment and weight loss include modulation of peripheral 5-HT_2A receptors and factors such as improved mood and improved sleep.

CONCLUSION

Mechanisms of flibanserin-induced weight loss have not been well characterized but may involve indirect beneficial effects on peripheral 5-HT_2A receptors and central regulation of mood and sleep. Future research may better elucidate the links between sexual function and weight management and the mechanism(s) by which flibanserin use may result in weight loss. Simon JA, Kingsberg SA, Goldstein I, et al. Weight Loss in Women Taking Flibanserin for Hypoactive Sexual Desire Disorder (HSDD): Insights into Potential Mechanisms. Sex Med Rev 2019;7:575-586.

Evaluation of Flibanserin Safety: Comparison with Other Serotonergic Medications

INTRODUCTION

Flibanserin, a multifunctional serotonin agonist and antagonist, is approved by the U.S. Food and Drug Administration (FDA) for treatment of acquired, generalized hypoactive sexual desire disorder in premenopausal women. During the FDA's review of flibanserin, concerns were raised about the risks of hypotension, syncope, and sedation-related adverse events, which increase with alcohol use. Based on the results of an alcohol challenge study, the FDA required a boxed warning and alcohol contraindication in the flibanserin prescribing information, as part of a risk evaluation and mitigation strategy program.

AIM

To evaluate the adverse event profile of flibanserin in the context of that seen with other medications that affect serotonin in the brain and are commonly prescribed for women.

METHODS

This was a review of data provided in the product prescribing information for flibanserin, selective serotonin reuptake inhibitors, serotonin-norepinephrine reuptake inhibitors, other serotonergic antidepressants, and triptans.

MAIN OUTCOME MEASURES

The incidence of adverse events was assessed.

RESULTS

The incidences of hypotension, syncope, and sedation-related adverse events (eg, dizziness, somnolence, fatigue) in studies of flibanserin were within the ranges observed for serotonergic antidepressants; the rates of these adverse events were generally lower with triptan medications. Other flibanserin-associated adverse events (eg, nausea, insomnia, dry mouth) occurred more commonly in patients taking antidepressant medications.

CONCLUSION

Although medications that affect the serotonin system have varying adverse event profiles (likely mediated by differences in serotonin-related mechanisms of action, specific brain structures affected, and effects on other neurotransmitter systems), the occurrence of central nervous system-related adverse events was not dissimilar between flibanserin and serotonergic antidepressants. Kingsberg SA, McElroy SL, Clayton AH. Evaluation of Flibanserin Safety: Comparison with Other Serotonergic Medications. Sex Med Rev 2019;7:380-392.

eToxPred: a machine learning-based approach to estimate the toxicity of drug candidates

BACKGROUND

The efficiency of drug development defined as a number of successfully launched new pharmaceuticals normalized by financial investments has significantly declined. Nonetheless, recent advances in high-throughput experimental techniques and computational modeling promise reductions in the costs and development times required to bring new drugs to market. The prediction of toxicity of drug candidates is one of the important components of modern drug discovery.

RESULTS

In this work, we describe eToxPred, a new approach to reliably estimate the toxicity and synthetic accessibility of small organic compounds. eToxPred employs machine learning algorithms trained on molecular fingerprints to evaluate drug candidates. The performance is assessed against multiple datasets containing known drugs, potentially hazardous chemicals, natural products, and synthetic bioactive compounds. Encouragingly, eToxPred predicts the synthetic accessibility with the mean square error of only 4% and the toxicity with the accuracy of as high as 72%.

CONCLUSIONS

eToxPred can be incorporated into protocols to construct custom libraries for virtual screening in order to filter out those drug candidates that are potentially toxic or would be difficult to synthesize. It is freely available as a stand-alone software at https://github.com/pulimeng/etoxpred .

Flow-oriented synthetic design in the continuous preparation of the aryl piperazine drug flibanserin

The first integrated continuous-flow synthesis of the drug substance flibanserin was developed, using an uninterrupted four-step sequence, via an unprecedented route.

Ignorance Is Not Bliss: If We Don't Understand Hypoactive Sexual Desire Disorder, How Can Flibanserin Treat It? Commentary

BACKGROUND

Female sexual dysfunction (FSD) affects as many as 1 in every 3 women, with a significant portion of these with hypoactive sexual desire disorder (HSDD). These figures alone present significant psychological and pharmacologic challenges. Partly in response to this situation, in 2015 the US Food and Drug Administration approved flibanserin for the treatment of HSDD. This approval has drawn criticism on the grounds of efficacy and necessity.

AIM

To better inform potential consumers about FSD, flibanserin and other interventions for the treatment of HSDD, the importance of understanding the mechanism of FSD, and the efficacy of flibanserin and to review existing relevant knowledge.

METHODS

A literature review of extant clinic studies and theoretical discussion articles was performed.

OUTCOMES

Efficacy of flibanserin for addressing symptoms associated with HSDD in premenopausal women.

RESULTS

Extant literature and empirical evidence suggest that the efficacy of flibanserin for the treatment of HSDD in premenopausal women is at least questionable.

CLINICAL TRANSLATION

Clinicians considering the prescription of flibanserin would be well advised to appreciate some of the controversies concerning the efficacy of the drug.

STRENGTHS AND LIMITATIONS

The prohibitive usage guidelines, tenuous risk-benefit profile, and considerable cost of use of flibanserin are each worthy of consideration. Flibanserin thus far has been trialed in only a narrow patient range: premenopausal women in long-term relationships with acquired or generalized HSDD.

CONCLUSIONS

Although we acknowledge that the discovery and use of flibanserin constitute a compelling narrative, we conclude by questioning the specific efficacy and necessity of flibanserin in providing a treatment for HSDD in women. Anderson R, Moffatt CE. Ignorance Is Not Bliss: If We Don't Understand Hypoactive Sexual Desire Disorder, How Can Flibanserin Treat It?

COMMENTARY

J Sex Med 2018;15:273-283.

Sexual and Marital Dysfunction in Women With Gynecologic Cancer

OBJECTIVE

Sexual dysfunction can be a long-term issue for women with gynecologic cancer. This study assesses the extent of sexual and marital dysfunction women face following treatment of a gynecologic cancer.

METHODS

A cross-sectional study of women with gynecologic cancer was conducted using a 181-item survey. Sexual dysfunction was measured by change in the Female Sexual Function Index score; marital dysfunction was measured by change in Intimate Bond Measure from prediagnosis to posttreatment. Paired t tests and Fisher exact test were used to compare women with dysfunction to those without dysfunction.

RESULTS

Three hundred twenty women were enrolled (mean age, 56.0 [SD, 12.0] years). Among all women, sexual function declined from a score of 21.3 (SD, 10.4) prior to 15.3 (SD, 10.2) (P < 0.001), and sexual activity decreased from 6.1 (SD, 6.8) to 2.6 (SD, 4.9) times per month following treatment (P < 0.001). Among the 208 women who were sexually active at the time of study, sexual dysfunction after treatment was associated with younger age (50.9 [SD, 11.7] years to 57.3 [SD, 12.3] years), ovarian (40.7% vs 30.7%) or cervical (21.0% vs 10.2%) cancer diagnosis, chemotherapy treatment (72.8% vs 50.4%), and being in a relationship (97.3% vs 82.7%). Among women in relationships, 27% experienced marital dysfunction.

CONCLUSIONS

Women who are younger, have an ovarian or cervical cancer diagnosis, receive chemotherapy, or are in a committed relationship are at particularly high risk of sexual dysfunction. These women should be provided information about the risks associated with their cancer treatment.

Understanding the Role of Serotonin in Female Hypoactive Sexual Desire Disorder and Treatment Options

BACKGROUND

The neurobiology of sexual response is driven in part by dopamine and serotonin-the former modulating excitatory pathways and the latter regulating inhibitory pathways. Neurobiological underpinnings of hypoactive sexual desire disorder (HSDD) are seemingly related to overactive serotonin activity that results in underactive dopamine activity. As such, pharmacologic agents that decrease serotonin, increase dopamine, or some combination thereof, have therapeutic potential for HSDD.

AIM

To review the role of serotonin in female sexual function and the effects of pharmacologic interventions that target the serotonin system in the treatment of HSDD.

METHODS

Searches of the Medline database for articles on serotonin and female sexual function.

OUTCOMES

Relevant articles from the peer-reviewed literature were included.

RESULTS

Female sexual response is regulated not only by the sex hormones but also by several neurotransmitters. It is postulated that dopamine, norepinephrine, oxytocin, and melanocortins serve as key neuromodulators for the excitatory pathways, whereas serotonin, opioids, and endocannabinoids serve as key neuromodulators for the inhibitory pathways. Serotonin appears to be a key inhibitory modulator of sexual desire, because it decreases the ability of excitatory systems to be activated by sexual cues. Centrally acting drugs that modulate the excitatory and inhibitory pathways involved in sexual desire (eg, bremelanotide, bupropion, buspirone, flibanserin) have been investigated as treatment options for HSDD. However, only flibanserin, a multifunctional serotonin agonist and antagonist (5-hydroxytryptamine [5-HT]_1A receptor agonist and 5-HT_2A receptor antagonist), is currently approved for the treatment of HSDD.

CLINICAL IMPLICATIONS

The central serotonin system is 1 biochemical target for medications intended to treat HSDD.

STRENGTHS AND LIMITATIONS

This narrative review integrates findings from preclinical studies and clinical trials to elucidate neurobiological underpinnings of HSDD but is limited to 1 neurotransmitter system (serotonin).

CONCLUSION

Serotonin overactivity is a putative cause of sexual dysfunction in patients with HSDD. The unique pharmacologic profile of flibanserin tones down inhibitory serotonergic function and restores dopaminergic and noradrenergic function. Croft HA. Understanding the Role of Serotonin in Female Hypoactive Sexual Desire Disorder and Treatment Options. J Sex Med 2017;14:1575-1584.

5-HT1A and 5-HT2A receptors affinity, docking studies and pharmacological evaluation of a series of 8-acetyl-7-hydroxy-4-methylcoumarin derivatives

In this work we describe the synthesis, docking studies and biological evaluation of a focused library of novel arylpiperazinyl derivatives of 8-acetyl-7-hydroxy-4-methylcoumarin. The new compounds were screened for their 5-HT_1A and 5-HT_2A receptor affinity. Among the evaluated compounds, six displayed high affinities to 5-HT_1A receptors (4a-0.9 nM, 6a-0.5 nM, 10a-0.6 nM, 3b-0.9 nM, 6b-1.5 nM, 10b-1 nM). Compound 6a and 10a bearing a bromo- or methoxy- substituent in ortho position of the piperazine phenyl ring, were identified as potent antagonists of the 5-HT_1A receptors. In the tail suspension test, mice injected with 6a showed a dose-dependent increase in depressive-like behavior that was related to a decrease in locomotor activity. Compound 10a did not decrease or prolong immobility time nor did it affect home cage activity. Molecular docking studies using 5-HT_1A and 5-HT_2A homology models revealed structural basis of the high affinity of ortho-substituted derivatives and subtle changes in amino acid interactions patterns depending on the length of the alkyl linker.

Effects of Flibanserin on the Pharmacokinetics of a Combined Ethinylestradiol/Levonorgestrel Oral Contraceptive in Healthy Premenopausal Women: A Randomized Crossover Study

PURPOSE

This study aimed to investigate the effect of steady-state exposure to flibanserin, a 5-HT_1A agonist/5-HT_2A antagonist approved for the treatment of hypoactive sexual desire disorder in premenopausal women, on the single-dose pharmacokinetics of the contraceptive steroids ethinylestradiol and levonorgestrel in healthy premenopausal women.

METHODS

Healthy female volunteers (N = 24) received 2 single doses of a combined oral contraceptive containing ethinylestradiol 30 μg and levonorgestrel 150 μg, either alone (reference) or preceded by treatment with flibanserin 100 mg once daily for 14 days (test). The 2 treatments were given in randomized order, with a 4-week washout period following the last administration of the first treatment. Plasma concentrations of ethinylestradiol and levonorgestrel were measured over 48 hours after dosing for the determination of pharmacokinetic parameters; the primary end points were C_max and AUC_0-∞ of ethinylestradiol and levonorgestrel.

FINDINGS

Of the 24 women enrolled (mean age, 38.0 years), 23 completed the study. Mean (SD) C_max and AUC_0-∞ values of ethinylestradiol were 66.7 (16.3) pg/mL and 693 (268) pg · h/mL, respectively, following the oral contraceptive alone, and 72.7 (25.5) pg/mL and 740 (235) pg · h/mL, respectively, when the oral contraceptive was preceded by flibanserin. In both cases, the 90% CIs of the reference/test ratios of C_max and AUC_0-∞ were within the range of 80% to 125%, indicating that flibanserin had no significant effect on the pharmacokinetic properties of ethinylestradiol. Similarly, the mean (SD) C_max and AUC_0-∞ values of levonorgestrel were 5.0 (1.6) ng/mL and 52.2 (18.7) ng · h/mL, respectively, with the oral contraceptive alone, and 5.0 (1.6) ng/mL and 53.3 (20.4) ng · h/mL, respectively, following flibanserin; again, in both cases, the 90% CIs of the reference/test ratios were within the range of 80% to 125%, indicating that flibanserin had no significant effect on the pharmacokinetic properties of levonorgestrel. All adverse events were mild to moderate in intensity (incidence: 12.5% and 70.8% with ethinylestradiol/levonorgestrel treatment alone and following administration of flibanserin, respectively).

IMPLICATIONS

Pretreatment with flibanserin 100 mg once daily for 2 weeks did not produce a clinically relevant change in oral contraceptive drug exposure following single-dose administration of ethinylestradiol/levonorgestrel. This finding is relevant to women with hypoactive sexual desire disorder who might prefer oral contraceptives to other forms of birth control. EudraCT No: 2006-006960-46.

Flibanserin in Postmenopausal Women With Hypoactive Sexual Desire Disorder: Results of the PLUMERIA Study

BACKGROUND

Hypoactive sexual desire disorder (HSDD) is a common sexual disorder in younger and older women. Flibanserin is approved for the treatment of acquired generalized HSDD in premenopausal women only. The efficacy of flibanserin for postmenopausal women with HSDD was demonstrated in the first of two North American randomized, double-blinded, placebo-controlled trials (SNOWDROP).

AIM

To evaluate the safety and efficacy of flibanserin in postmenopausal women with HSDD in a second randomized, double-blinded, placebo-controlled trial (PLUMERIA).

METHODS

Naturally postmenopausal women were randomly assigned to receive flibanserin (100 mg/d) or placebo. Efficacy outcomes were assessed using the last-observation-carried-forward imputation method.

OUTCOMES

Safety assessment included incidence of adverse events. Primary efficacy outcomes were the number of satisfying sexual events and the Female Sexual Function Index desire domain (FSFI-d) score.

RESULTS

The study population (flibanserin, n = 376; placebo, n = 369) included primarily white women (84.7%), with a mean age of 56.1 years and a mean HSDD duration of 5.0 years. When the study was discontinued early by the sponsor, 45.3% of randomly assigned patients had completed week 16 (which served as the primary analysis time point). The most common adverse events in flibanserin-treated patients were insomnia (7.7%), somnolence (6.9%), and dizziness (6.4%). Improvement from baseline to week 16 (last-observation-carried-forward) in FSFI-d score was significantly greater for flibanserin compared with placebo (P = .011); however, the between-group comparison for satisfying sexual events did not reach statistical significance.

CLINICAL IMPLICATIONS

Considered with the findings of the previous randomized controlled trial (SNOWDROP), the results of this study support the safety and efficacy of flibanserin in postmenopausal women.

STRENGTHS AND LIMITATIONS

This was a well-designed randomized, placebo-controlled trial. A key limitation was early discontinuation by the study sponsor, which decreased the sample size. In addition, the validity of satisfying sexual events as a primary outcome measurement in HSDD studies has been called into question (but was required by the US Food and Drug Administration as a primary end point in studies of female sexual dysfunction at the time this study was conducted).

CONCLUSION

Flibanserin was generally well tolerated in this population of naturally postmenopausal women. Despite the greatly decreased power to detect improvement compared with placebo on the efficacy measurements used, results suggest that flibanserin could be efficacious in postmenopausal women with HSDD. Portman DJ, Brown L, Yuan J, et al. Flibanserin in Postmenopausal Women With Hypoactive Sexual Desire Disorder: Results of the PLUMERIA Study. J Sex Med 2017;14:834-842.

Flibanserin - the female Viagra?

This article provides a clinically relevant review of the first medication approved by the US Food and Drug Administration for hypoactive sexual desire disorder (HSDD) in premenopausal women. In this short piece, the human sexual response cycle and its relevance to HSDD will be described as well as the pharmacological mechanism of action of flibanserin. Finally, efficacy and safety data of this new medication will be summarised.

The Role of Ovarian Hormones and the Medial Amygdala in Sexual Motivation

Purpose

Although research into the neurobiology of sexual desire in women is active, relatively little is understood about the origins of sexual motivation in women. The purpose of our review is to discuss factors that influence a central sexual motivate state and generalized arousal as potential drivers of sexual motivation in women and female rats.

Recent Findings

Sexual motivation is the product of interactions of the central motive state and salient sexually-relevant cues. Ovarian hormones and generalized arousal influence the central motive state, and endogenous levels of estradiol and progesterone correlate with sexual motivation and behavior in women. The amygdala is a key integratory site for generalized arousal and sexual sensory stimulation, which could then increase sexual motivation through its downstream projections.

Summary

Our model of enhanced female sexual motivation suggests that the combined effects of dopamine and progesterone receptor activation in the medial amygdala increases the incentive properties of a sexual stimulus. Further study into the interactions of ovarian hormones and mediators of generalized arousal on the processing of sexually-relevant cues informs our understanding of the neurobiology of female sexual motivation and could lead to the development of therapeutics to treat the dysfunctions of sexual desire in women.

Effect of Flibanserin Treatment on Body Weight in Premenopausal and Postmenopausal Women with Hypoactive Sexual Desire Disorder: A Post Hoc Analysis

BACKGROUND

Flibanserin, a 5-HT_1A agonist and 5-HT_2A antagonist, is indicated for the treatment of acquired, generalized hypoactive sexual desire disorder (HSDD) in premenopausal women. This post hoc analysis evaluated the effect of flibanserin treatment on body weight in premenopausal and postmenopausal women with HSDD.

MATERIALS AND METHODS

This analysis included three 24-week, double-blind, placebo-controlled studies of flibanserin 100 mg each bedtime (qhs) in premenopausal women, a similarly designed study in postmenopausal women, and a 52-week, open-label extension study in premenopausal women.

RESULTS

In a pooled analysis of premenopausal women, mean baseline body mass index (BMI) was 27.0 kg/m² in the flibanserin group (n = 1227) and 26.8 kg/m² in the placebo group (n = 1238). Among patients who completed 24 weeks of treatment, least squares (LS) mean weight change was -1.4 kg in the flibanserin group (n = 1010) and -0.1 kg in the placebo group (n = 1066; p < 0.0001). Weight loss ≥5% from baseline was reported in 21.0% of patients who received flibanserin and 7.8% of patients who received placebo; weight loss ≥10% was reported in 3.8% and 2.0% of patients, respectively. In postmenopausal women, mean baseline BMI was 27.7 kg/m² in the flibanserin group (n = 467) and 27.3 kg/m² in the placebo group (n = 480). LS mean weight change at week 24 was -1.8 kg in the flibanserin group (n = 385) and -0.1 kg in the placebo group (n = 425; p < 0.0001), with weight loss ≥5% reported in 24.7% and 7.3% of patients, respectively, and weight loss ≥10% reported in 5.2% and 1.7%, respectively. In HSDD patients with >12 months (n = 880) and >18 months (n = 637) of exposure to flibanserin, mean weight change was -1.0 and -1.2 kg, respectively; 25.4% and 26.9% of patients, respectively, experienced weight loss ≥5% from baseline, and 7.8% and 8.4%, respectively, experienced weight loss ≥10%.

CONCLUSIONS

Women treated with flibanserin for HSDD may experience weight loss.

Marine Inspired 2-(5-Halo-1H-indol-3-yl)-N,N-dimethylethanamines as Modulators of Serotonin Receptors: An Example Illustrating the Power of Bromine as Part of the Uniquely Marine Chemical Space

In previous studies, we have isolated several marine indole alkaloids and evaluated them in the forced swim test (FST) and locomotor activity test, revealing their potential as antidepressant and sedative drug leads. Amongst the reported metabolites to display such activities was 5-bromo-N,N-dimethyltryptamine. Owing to the importance of the judicious introduction of halogens into drug candidates, we synthesized two series built on a 2-(1H-indol-3-yl)-N,N-dimethylethanamine scaffold with different halogen substitutions. The synthesized compounds were evaluated for their in vitro and in vivo antidepressant and sedative activities using the mouse forced swim and locomotor activity tests. Receptor binding studies of these compounds to serotonin (5-HT) receptors were conducted. Amongst the prepared compounds, 2-(1H-indol-3-yl)-N,N-dimethyl-2-oxoacetamide (1a), 2-(5-bromo-1H-indol-3-yl)-N,N-dimethyl-2-oxoacetamide (1d), 2-(1H-indol-3-yl)-N,N-dimethylethanamine (2a), 2-(5-chloro-1H-indol-3-yl)-N,N-dimethylethanamine (2c), 2-(5-bromo-1H-indol-3-yl)-N,N-dimethylethanamine (2d), and 2-(5-iodo-1H-indol-3-yl)-N,N-dimethylethanamine (2e) have been shown to possess significant antidepressant-like action, while compounds 2c, 2d, and 2e exhibited potent sedative activity. Compounds 2a, 2c, 2d, and 2e showed nanomolar affinities to serotonin receptors 5-HT_1A and 5-HT₇. The in vitro data indicates that the antidepressant action exerted by these compounds in vivo is mediated, at least in part, via interaction with serotonin receptors. The data presented here shows the valuable role that bromine plays in providing novel chemical space and electrostatic interactions. Bromine is ubiquitous in the marine environment and a common element of marine natural products.

Flibanserin: From Bench to Bedside

INTRODUCTION

The process of approval for flibanserin (trade name Addyi) has been associated with controversy since before its approval on August 18, 2015. This argument centered on challenges to the validity of the diagnosis of hypoactive sexual desire disorder in women and the safety and efficacy of the drug.

AIM

To explore the process of Food and Drug Administration (FDA) approval for flibanserin and delve further into the research, concerns, and various roadblocks to its approval.

METHODS

A literature review was undertaken using the terms flibanserin and hypoactive sexual desire disorder and relevant commentary from supporters and critics regarding the medication and difficulties leading up to approval.

MAIN OUTCOME MEASURES

Review of the process of FDA approval of a medication to treat hypoactive sexual desire disorder and research published exploring the efficacy and safety of flibanserin.

RESULTS

Before flibanserin, there were no drugs approved to treat hypoactive sexual desire disorder, which has a reported estimated incidence of 10% of women. For studying the effectiveness of flibanserin, the FDA required satisfying sexual events as the primary end point, although this end point does not measure level of desire or the associated distress. The satisfying sexual event measurement was significant across all three flibanserin trials in premenopausal women, as was an increase in desire according to the Female Sexual Function Index desire domain and a decrease in distress as recorded with the Female Sexual Distress Scale-Revised, Item 13. Safety concerns centered on the incidence of sedation, syncope, hypotension, and the interaction of flibanserin with alcohol and CYP3A4 inhibitors. Additional targeted challenge studies were mandated by the FDA.

CONCLUSION

The process of approval of flibanserin was lengthy. This was due in part to it being the first drug in its class and one with no clear guidance on study design from the FDA or roadmap for development and approval. Dooley EM, Miller MK, Clayton AH. Flibanserin: From Bench to Bedside. Sex Med Rev 2017;5:461-469.

Flibanserin Efficacy and Safety in Premenopausal Women With Generalized Acquired Hypoactive Sexual Desire Disorder

INTRODUCTION

Flibanserin is a postsynaptic 5-HT-1A agonist and 5-HT-2A antagonist for the treatment of generalized acquired hypoactive sexual desire disorder in premenopausal women.

AIM

To review and evaluate the efficacy and safety of flibanserin.

METHODS

We review and critique the appropriateness of the co-primary and secondary end points used in the flibanserin pivotal trial research program. We review the efficacy and safety parameters of this drug based on the published literature and related sources.

MAIN OUTCOME MEASURES

Pivotal trial primary and secondary end points and safety profile data from the flibanserin development program.

RESULTS

Our review identified instances of poor fit of two primary trial pivotal trial end points with the hypoactive sexual desire disorder construct: satisfying sexual events and electronic daily diary assessments of the most intense level of sexual desire experienced each day. Efficacy findings of the flibanserin pivotal trials program were positive for satisfying sexual events, not positive for electronic daily diary assessments of the most intense level of sexual desire experienced, and positive for secondary end points of the Female Sexual Function Index desire domain and overall measurements and the Female Sexual Distress Scale-Revised desire-specific and overall measurements. Safety data from the clinical trial program showed a reasonable safety profile.

CONCLUSION

Flibanserin has demonstrated efficacy on appropriate measurements of the hallmarks of hypoactive sexual desire disorder-experience of absent or decreased sexual desire that is persistent over time and distressing-and the safety profile of flibanserin is acceptable. Fisher WA, Pyke RE. Flibanserin Efficacy and Safety in Premenopausal Women With Generalized Acquired Hypoactive Sexual Desire Disorder. Sex Med Rev 2017:5;445-460.

The pharmacodynamic effects of combined administration of flibanserin and alcohol

WHAT IS KNOWN AND OBJECTIVE

Flibanserin is a serotonin 5-HT_1A agonist and 5-HT_2A antagonist approved for the treatment of acquired, generalized hypoactive sexual desire disorder (HSDD) in premenopausal women. Because of the increased risk of hypotension- and syncope-related adverse events (AEs) observed with coadministration of flibanserin and alcohol, alcohol use is contraindicated. To provide a more comprehensive understanding of the interaction between flibanserin and alcohol, the results of a dedicated phase 1 alcohol-interaction study and a pooled analysis of phase 3 studies of premenopausal women with HSDD are presented.

METHODS

In the phase 1 study, healthy participants (males [n=23] and females [n=2]) were randomly assigned to one of five sequence groups, which determined the order in which they were to receive flibanserin 100 mg or placebo, with or without ethanol 0.4 g/kg or 0.8 g/kg. Change from baseline in seated blood pressure, orthostatic vital signs, AEs and visual analogue scale sedation outcomes were examined. Blood samples were collected at baseline and for up to 4 hours after dosing to determine flibanserin area under the plasma concentration-time curve from 0 to 4 hours (AUC_0-4 ). Pooled data from five phase 3 studies of patients receiving flibanserin 100 mg once daily (n=1543), or placebo (n=1905), were analysed.

RESULTS

In the phase 1 study, the incidence of hypotension and syncope increased when flibanserin was coadministered with ethanol. Sedation increased 20% and 27% from baseline with flibanserin plus ethanol 0.4 g/kg and 0.8 g/kg, respectively, at 4 hours post-dose. In the pooled analysis of phase 3 studies, 58.2% and 63.6% of participants receiving flibanserin or placebo, respectively, reported baseline alcohol use. In patients receiving flibanserin, fatigue and dizziness occurred more frequently in patients with vs. without alcohol use.

WHAT IS NEW AND CONCLUSION

Results from this study suggest that increased incidence of hypotension- and syncope-related events may result from a pharmacodynamic interaction between flibanserin and alcohol, although the clinical significance of these interactions in real-world populations remains unclear.

Decreased lymphocyte dopamine transporter in romantic lovers

OBJECTIVE

The role of dopamine (DA) in romantic love is suggested by different evidence and is supported by the findings of some brain imaging studies. The DA transporter (DAT) is a key structure in regulating the concentration of the neurotransmitter in the synaptic cleft. Given the presence of DAT in blood cells, the present study aimed to explore it in resting lymphocytes of 30 healthy subjects of both sexes in the early stage of romantic love (no longer than 6 months), as compared with 30 subjects involved in a long-lasting relationship.

METHODS

All subjects had no physical or psychiatric illness. The DAT was measured by means of the [3H]-WIN 35,428 binding and the [3H]-DA reuptake to resting lymphocytes membranes. Romantic love was assessed by a specific questionnaire developed by us.

RESULTS

The results showed that the subjects in the early phase of romantic love had a global alteration of the lymphocyte DAT involving both a decreased number of proteins (Bmax) and a reduced functionality (Vmax).

CONCLUSIONS

Taken together, these findings would indicate the presence of increased levels of DA in romantic love that, if paralleled by similar concentrations in the brain, would explain some peculiar features of this human feeling.

Retinal Neuroprotective Effects of Flibanserin, an FDA-Approved Dual Serotonin Receptor Agonist-Antagonist

PURPOSE

To assess the neuroprotective effects of flibanserin (formerly BIMT-17), a dual 5-HT1A agonist and 5-HT2A antagonist, in a light-induced retinopathy model.

METHODS

Albino BALB/c mice were injected intraperitoneally with either vehicle or increasing doses of flibanserin ranging from 0.75 to 15 mg/kg flibanserin. To assess 5-HT1A-mediated effects, BALB/c mice were injected with 10 mg/kg WAY 100635, a 5-HT1A antagonist, prior to 6 mg/kg flibanserin and 5-HT1A knockout mice were injected with 6 mg/kg flibanserin. Injections were administered once immediately prior to light exposure or over the course of five days. Light exposure lasted for one hour at an intensity of 10,000 lux. Retinal structure was assessed using spectral domain optical coherence tomography and retinal function was assessed using electroretinography. To investigate the mechanisms of flibanserin-mediated neuroprotection, gene expression, measured by RT-qPCR, was assessed following five days of daily 15 mg/kg flibanserin injections.

RESULTS

A five-day treatment regimen of 3 to 15 mg/kg of flibanserin significantly preserved outer retinal structure and function in a dose-dependent manner. Additionally, a single-day treatment regimen of 6 to 15 mg/kg of flibanserin still provided significant protection. The action of flibanserin was hindered by the 5-HT1A antagonist, WAY 100635, and was not effective in 5-HT1A knockout mice. Creb, c-Jun, c-Fos, Bcl-2, Cast1, Nqo1, Sod1, and Cat were significantly increased in flibanserin-injected mice versus vehicle-injected mice.

CONCLUSIONS

Intraperitoneal delivery of flibanserin in a light-induced retinopathy mouse model provides retinal neuroprotection. Mechanistic data suggests that this effect is mediated through 5-HT1A receptors and that flibanserin augments the expression of genes capable of reducing mitochondrial dysfunction and oxidative stress. Since flibanserin is already FDA-approved for other indications, the potential to repurpose this drug for treating retinal degenerations merits further investigation.

Psychosexual disorders and dermatologists

Sexual problems that are psychological in origin, rather than physiological, are called psychosexual disorders. Multiple factors, such as general health of the patient, chronic illnesses, psychiatric/psychological disorders, and socio-cultural factors, alone or in combination can be attributed to the development of psychosexual dysfunctions. The symptoms of these disorders vary for each individual and differ with gender. These disorders may be categorized as sexual dysfunction, paraphilias, and gender identity disorders. Dermatologists are sometimes consulted for sexual dysfunctions in their routine practice by the patients visiting sexually transmitted infections (STI) clinics because a majority of the patients believe that these problems are caused by dysfunctions in the sex organs, and because people are hesitant to go to sexuality clinics and psychiatrists for such problems. Sometimes these patients are referred from other specialties such as urology or gynecology; most often, we attempt to search for STIs or other dermatoses on the genitalia and refer them back. We often underestimate the prevalence of sexual concerns of the patients or feel uncomfortable discussing matters of sexuality with them. Dermatologists should understand basic sexual medicine and ask patients for sexual problems. They should be trained to manage such patients accordingly. In this review, we will be focusing on sexual dysfunctions, their etiopathogenesis, and management from a dermatologist's perspective.