Flibanserin

Key facts

• Flibanserin is a daily tablet, taken at bedtime, used to treat acquired, generalized hypoactive sexual desire disorder in premenopausal women, low sexual desire that causes distress and was not always present.
• It carries a boxed warning: combining flibanserin with alcohol, or with medicines that inhibit the CYP3A4 enzyme, can cause severe low blood pressure, fainting and loss of consciousness. Alcohol must be avoided while taking it.
• It does not work as an on-demand medicine; it is taken every night regardless of sexual activity, and it can take several weeks to show an effect.
• Seek urgent care for fainting, severe dizziness or a very slow heartbeat.

What flibanserin treats

Flibanserin treats acquired, generalized hypoactive sexual desire disorder in premenopausal women. "Acquired" means the low desire developed after a period of normal sexual desire, and "generalized" means it is not limited to a specific partner or situation. It is not used for low desire caused by a medical condition, a relationship problem, or as a side effect of another medicine, and it is not approved for use in men or in postmenopausal women.

How flibanserin works

Flibanserin acts on brain chemistry rather than on blood flow to the genitals. It is thought to work by rebalancing the activity of two brain chemical systems involved in sexual desire and inhibition, namely serotonin and dopamine and noradrenaline. Lowering excess serotonin-driven inhibition while supporting dopamine and noradrenaline signalling is believed to restore sexual desire over time, though the mechanism is not fully established.

Before you take it

• Do not take flibanserin if you drink alcohol, have liver disease, or take a moderate or strong CYP3A4 inhibitor, which includes certain antifungals, some antibiotics, some HIV medicines and grapefruit juice.
• Tell your prescriber about all other medicines, since flibanserin also interacts with strong CYP3A4 inducers, which can make it less effective.
• It is not approved for use in men, in postmenopausal women, or for low desire caused by another medical or psychiatric condition, relationship difficulties, or another medicine.
• Take it only at bedtime, since drowsiness and low blood pressure are more likely if it is taken earlier in the day.

Side effects

Common effects include dizziness, drowsiness, nausea, fatigue and dry mouth.

Stop and seek urgent medical care for any of these:

• Fainting or loss of consciousness.
• Severe dizziness or a sensation the room is spinning.
• A very slow or irregular heartbeat.
• Severe drowsiness that affects your ability to stay awake during the day.

Safety essentials

• The boxed warning is the defining safety fact for flibanserin: never combine it with alcohol, and never combine it with CYP3A4 inhibitors, since together they can cause severe low blood pressure and fainting.
• Avoid activities that require full alertness, such as driving, until you know how flibanserin affects you the morning after a dose.
• If treatment has not improved your symptoms after eight weeks, your prescriber will usually review whether to continue it.

This page is educational and does not replace advice from a doctor or pharmacist who knows your health history.