Flibanserin represents a significant development in the pharmacological management of acquired, generalized Hypoactive Sexual Desire Disorder (HSDD) in premenopausal women. As a multifunctional serotonin agonist and antagonist (MSAA), it operates centrally to modulate neurotransmitter activity, specifically targeting the neurobiological pathways implicated in sexual motivation. This non-hormonal, oral tablet is indicated for patients experiencing clinically significant distress due to a persistent lack of sexual desire that is not attributable to a co-existing medical or psychiatric condition, medication, or relationship discord. Its mechanism distinguishes it from previous approaches, offering a targeted neuroscientific intervention.

Features

• Active pharmaceutical ingredient: Flibanserin 100 mg
• Pharmacologic class: Multifunctional serotonin agonist and antagonist (MSAA)
• Formulation: Oral tablet
• Mechanism: Acts centrally on 5-HT1A (agonist) and 5-HT2A (antagonist) receptors; also exhibits dopamine D4 receptor partial agonism
• Prescription status: Available only under a Risk Evaluation and Mitigation Strategy (REMS) program due to potential for hypotension and syncope
• Recommended administration: Once daily at bedtime

Benefits

• Increases the number of satisfying sexual events (SSEs) as reported in clinical trials
• Reduces distress associated with low sexual desire, a core diagnostic criterion for HSDD
• Offers a non-hormonal treatment option for premenopausal women
• Functions through a central nervous system mechanism, targeting the neurobiology of desire
• Provides a validated pharmacologic approach for a condition previously lacking FDA-approved medical therapies
• Can be integrated into a broader therapeutic strategy that may include psychological counseling

Common use

Flibanserin is specifically indicated for the treatment of premenopausal women with acquired, generalized Hypoactive Sexual Desire Disorder (HSDD). This diagnosis is characterized by a persistent or recurrent deficiency or absence of sexual fantasies and desire for sexual activity, causing marked distress or interpersonal difficulty. It is termed “acquired” when it occurs in a patient who previously experienced no such issues and “generalized” when it is not situational or partner-specific. It is critical that this low desire is not better explained by another medical condition (e.g., major depressive disorder, endocrine abnormalities), a comorbid psychiatric condition, the effects of a substance or medication, or severe relationship distress. Its use is confined to this specific patient population and is not approved for men or postmenopausal women.

Dosage and direction

The recommended dosage is 100 mg taken orally once daily, at bedtime. Administration at bedtime is mandated to mitigate the risks of hypotension, syncope, and central nervous system depression (e.g., somnolence, sedation). The tablet should be swallowed whole and can be taken with or without food; however, consistent administration relative to food may help manage variability in absorption. Patients must be advised not to consume alcohol during treatment with flibanserin due to a profound interaction that potentiates the risk of severe hypotension and syncope. Dose titration is not recommended, and the 100 mg dose should not be exceeded.

Precautions

Patients and prescribers must be enrolled in the FDA-mandated REMS program. Prior to initiation, assess hepatic function via blood tests. Use is contraindicated in patients with hepatic impairment. Concomitant use with moderate or strong CYP3A4 inhibitors is contraindicated. Caution is advised in patients with hypotension or who are on antihypertensive medications or other drugs that can lower blood pressure. Patients should be cautioned about the potential for significant drowsiness and advised against engaging in activities requiring full alertness (e.g., driving, operating machinery) until they know how flibanserin affects them. A patient’s cardiovascular status should be considered before prescribing.

Contraindications

• Concomitant use with alcohol
• Hepatic impairment
• Concomitant use with moderate or strong CYP3A4 inhibitors (e.g., ketoconazole, fluconazole, erythromycin, verapamil, diltiazem, grapefruit juice)
• Concomitant use with other central nervous system depressants
• Hypersensitivity to flibanserin or any component of the formulation

Possible side effects

The most commonly reported adverse reactions (incidence ≥2% and greater than placebo) in clinical trials were:

• Dizziness
• Somnolence (sleepiness)
• Nausea
• Fatigue
• Insomnia
• Dry mouth
• Sedation
• Anxiety
• Constipation
• Abdominal pain Serious side effects include:
• Severe hypotension
• Syncope (fainting)
• Central nervous system depression

Drug interaction

Flibanserin is primarily metabolized by CYP3A4 and, to a lesser extent, by CYP2C19. Its pharmacokinetics are highly susceptible to drug interactions.

• Strong/Moderate CYP3A4 Inhibitors: Concomitant use is contraindicated. These drugs (e.g., ketoconazole, itraconazole, nefazodone, ritonavir, clarithromycin, grapefruit juice) significantly increase flibanserin exposure, raising the risk of severe hypotension and syncope.
• CYP2C19 Inhibitors: Concomitant use may increase flibanserin exposure. Use with caution.
• Alcohol: Contraindicated. Interaction can lead to profound hypotension, syncope, and CNS depression.
• CNS Depressants: Concomitant use with other sedating agents (e.g., benzodiazepines, narcotics, sleep aids) may potentiate sedation and hypotension.
• Other Hypotensive Agents: May have additive effects on blood pressure lowering.

Missed dose

If a dose is missed, it should be skipped. The patient should not double the next dose to make up for the missed one. The next dose should be taken at the usual time the following bedtime. Taking a double dose significantly increases the risk of adverse effects like hypotension and syncope.

Overdose

There is limited clinical experience with flibanserin overdose. Based on its pharmacologic profile, overdose would be expected to manifest as an exaggeration of its known adverse effects, including severe hypotension, syncope, and profound CNS depression (sedation, somnolence). There is no specific antidote. In case of suspected overdose, symptomatic and supportive measures are indicated, including continuous cardiovascular monitoring and measures to manage hypotension. Due to the risk of sudden loss of consciousness, the patient should be placed in a supine position with legs elevated if hypotensive. Gastric lavage or administration of activated charcoal may be considered if ingestion was recent. Hemodialysis is not expected to be effective in removing flibanserin.

Storage

Store flibanserin tablets at room temperature, between 20°C to 25°C (68°F to 77°F). Excursions are permitted between 15°C and 30°C (59°F and 86°F). Keep the medication in its original container to protect it from light and moisture. Keep out of reach of children and pets.

Disclaimer

This information is for educational purposes only and is not a substitute for professional medical advice, diagnosis, or treatment. Always seek the advice of your physician or other qualified health provider with any questions you may have regarding a medical condition or before starting any new treatment. Never disregard professional medical advice or delay in seeking it because of something you have read here. The information provided does not cover all possible uses, directions, precautions, drug interactions, or adverse effects.

Reviews

“Within the confines of its strict REMS protocol and appropriate patient selection, flibanserin offers a valuable, mechanism-specific tool for treating HSDD. The efficacy data, while modest in absolute terms, represents a statistically significant improvement over placebo for a condition with profound negative impacts on quality of life. The safety profile necessitates rigorous patient education and monitoring, particularly regarding alcohol contraindication and CYP3A4 interactions. It is not a panacea, but for the right patient, it can be a meaningful component of a comprehensive treatment plan.” – Clinical Psychopharmacologist

“Prescribing flibanserin requires a meticulous approach. The REMS program is not a formality; it is a critical component of safe use. The benefits in terms of increasing satisfying sexual events and reducing associated distress are real for a subset of premenopausal women, but they must be carefully weighed against the risks of hypotension and syncope. It is imperative to have a thorough discussion with the patient about lifestyle modifications, particularly complete alcohol abstinence.” – Specialist in Obstetrics and Gynecology