What is Flibanserin used for?

Flibanserin is a prescription medication often marketed under the trade name Addyi. It is primarily prescribed for premenopausal women experiencing hypoactive sexual desire disorder (HSDD). This condition is characterized by a persistent lack of sexual desire that can lead to distress or difficulty in interpersonal relationships. Originally developed by the pharmaceutical company Boehringer Ingelheim, the drug's rights were later acquired by Sprout Pharmaceuticals. Flibanserin stands out as a unique treatment option because, unlike other sexual dysfunction drugs, it targets the central nervous system rather than merely addressing physical factors.

The journey of Flibanserin to becoming an FDA-approved medication was convoluted. Initially, it was researched as an antidepressant, but its efficacy in that domain was unsatisfactory. However, during clinical trials, researchers observed an interesting side effect: some participants reported an increase in sexual desire. This observation redirected the focus of the drug's research, eventually leading to its approval by the FDA in August 2015 for the treatment of HSDD in premenopausal women.

Flibanserin Mechanism of Action

Flibanserin operates by modulating neurotransmitter activity in the brain, specifically targeting serotonin, dopamine, and norepinephrine systems. It works as a serotonin 5-HT1A receptor agonist and a 5-HT2A receptor antagonist. In simpler terms, it activates receptors that promote the release of serotonin while inhibiting receptors that would otherwise decrease serotonin levels. This dual action is believed to rebalance the levels of key neurotransmitters, thereby enhancing sexual desire.

The serotonin system is closely tied to mood regulation and inhibition, which likely explains the drug's initial exploration as an antidepressant. However, it is also intricately linked to sexual function. High levels of serotonin can inhibit sexual desire, while lower levels may facilitate it. By fine-tuning this balance, Flibanserin aims to alleviate the symptoms of HSDD. Furthermore, the drug's impact on dopamine and norepinephrine—neurotransmitters associated with pleasure and alertness—may also contribute to its effectiveness in increasing sexual desire.

How to Use Flibanserin

Flibanserin is administered orally in the form of a 100 mg tablet, typically taken once a day at bedtime. The reason for this timing is twofold: it helps to mitigate potential side effects like dizziness and drowsiness, and it aligns with the drug's pharmacokinetics, ensuring optimal absorption and effectiveness during sleep.

It's important to adhere strictly to the prescribed schedule to maintain consistent levels of the medication in the bloodstream. Missing a dose or taking it at irregular intervals can reduce its effectiveness. The onset of action may vary; some women report noticing changes within a few weeks, while for others, it may take up to 8 weeks to experience significant benefits.

A crucial aspect to remember is that alcohol consumption should be avoided while taking Flibanserin. The combination of alcohol and Flibanserin can significantly increase the risk of severe hypotension (low blood pressure) and syncope (fainting). Therefore, healthcare providers emphasize the importance of abstaining from alcohol during the course of treatment.

What is Flibanserin Side Effects

Like any medication, Flibanserin comes with a range of potential side effects. The most commonly reported ones include dizziness, sleepiness, nausea, fatigue, insomnia, and dry mouth. These are generally mild to moderate in severity and often diminish as the body adjusts to the medication.

However, there are also more severe side effects to be aware of. As mentioned earlier, the combination of Flibanserin and alcohol can lead to significant drops in blood pressure and fainting. Therefore, it’s crucial to discuss your alcohol consumption habits with your healthcare provider before starting this medication.

Other contraindications include liver impairment and the use of moderate to strong CYP3A4 inhibitors, which are drugs that can interfere with Flibanserin's metabolism. These inhibitors include certain antibiotics, antifungals, and antiretrovirals. Because Flibanserin is metabolized in the liver, any condition or medication that affects liver function can alter the drug's efficacy and safety.

Moreover, individuals with a history of depression or other mental health disorders should approach the use of Flibanserin cautiously. Although it is not an antidepressant, its impact on neurotransmitter levels can potentially exacerbate underlying mental health conditions. Therefore, a thorough medical history and consultation are essential before starting this medication.

What Other Drugs Will Affect Flibanserin

Flibanserin can interact with a variety of other medications, which can either increase the risk of side effects or reduce its effectiveness. As previously mentioned, any drugs that inhibit the CYP3A4 enzyme can significantly alter Flibanserin’s metabolism. This includes several classes of medications such as:

- Antibiotics: Erythromycin and ciprofloxacin
- Antifungals: Ketoconazole and itraconazole
- Antiretrovirals: Ritonavir and saquinavir
- Certain cardiovascular drugs: Verapamil and diltiazem

Additionally, combining Flibanserin with other CNS depressants such as benzodiazepines, opioids, or sleep aids can amplify drowsiness and sedation, further increasing the risk of accidental injury. Similarly, the use of medications that lower blood pressure, including antihypertensives and diuretics, can compound the risk of hypotension and syncope.

Over-the-counter herbal supplements, particularly those that affect liver enzymes, should also be used cautiously. St. John's Wort, for instance, is known to influence CYP3A4 activity and could potentially interfere with Flibanserin's metabolism.

Given these potential interactions, it is imperative to provide your healthcare provider with a complete list of all medications and supplements you are currently taking. This allows for a comprehensive review of potential drug interactions and helps in making informed decisions about the use of Flibanserin.

In summary, Flibanserin represents a novel approach to treating hypoactive sexual desire disorder in premenopausal women by targeting central neurotransmitter systems. While it offers a promising solution for many, it is not without its risks and potential side effects. Careful consideration and consultation with healthcare providers are essential to determine whether it is the right treatment option for you.