Flibansetrin has high affinity for serotonin receptors in the brain: it acts as an agonist on 5-HT1A and an antagonist on 5-HT2A. In vivo, flibanserin binds equally to 5-HT1A and 5-HT2A receptors. However, under higher levels of brain 5-HT (i.e., under stress), flibanserin may occupy 5-HT2A receptors in higher proportion than 5-HT(1A) receptors. It may also moderately antagonize D4 (dopamine) receptors and 5-HT2B and 5-HTB2C. Its action on neurotransmitter receptors may contribute to reduction in serotonin levels and increase in dopamine and norepinephrine levels, all of which may play part in reward processing.

Flibanserin is indicated for the treatment of premenopausal women with acquired, generalized hypoactive sexual desire disorder (HSDD), as characterized by low sexual desire that causes marked distress or interpersonal difficulty and is not due to:

• A co-existing medical or psychiatric condition,
• Problems within the relationship, or
• The effects of a medication or other drug substance.

Acquired HSDD refers to HSDD that develops in a patient who previously had no problems with sexual desire. Generalized HSDD refers to HSDD that occurs regardless of the type of stimulation, situation or partner.

The recommended dosage of Flibanserin is 100 mg administered orally once per day at bedtime. Flibanserin is dosed at bedtime because administration during waking hours increases the risks of hypotension, syncope, accidental injury, and central nervous system (CNS) depression (such as somnolence and sedation). If a dose of Flibanserin is missed at bedtime, instruct the patient to take the next dose at bedtime on the next day. Instruct the patient to not double the next dose.

Pediatric Use: Flibanserin is not indicated for use in pediatric patients.

Geriatric Use: Flibanserin is not indicated for use in geriatric patients. Safety and effectiveness have not been established in geriatric patients.

Flibanserin is contraindicated: with use of alcohol, with concomitant use with moderate or strong CYP3A4 inhibitors, in patients with hepatic impairment.

Most common adverse reactions are Dizziness, Somnolence, Nausea, Fatigue, Insomnia, Dry mouth.

Hypotension and Syncope with Flibanserin Alone: Patients with pre-syncope should immediately lie supine and promptly seek medical help if symptoms do not resolve.

Central Nervous System (CNS) Depression (e.g., Somnolence, Sedation): Can occur with Flibanserin alone. Exacerbated by other CNS depressants, and in settings where flibanserin concentrations are increased. Patients should avoid activities requiring full alertness (e.g., operating machinery or driving) until at least 6 hours after each dose and until they know how Flibanserin affects them.

Pregnancy & Lactation

There are no studies of Flibanserin in pregnant women to inform whether there is a drug-associated risk in humans. Flibanserin is excreted in rat milk. It is unknown whether flibanserin is present in human milk, whether Flibanserin has effects on the breastfed infant, or whether Flibanserin affects milk production. Because of the potential for serious adverse reactions including sedation in a breastfed infant, breastfeeding is not recommended during treatment with Flibanserin.