Flibanserin belongs to the class of medications called central nervous system agents. It is used to treat a condition called hypoactive sexual desire disorder (HSDD). This medication is intended for use by women 60 years of age or younger who have had a low sexual desire 75 to 100 per cent of the time, for a minimum of 6 months, and this low sexual desire is causing distress or problems with intimate relationships.

The exact way that flibanserin works is not known. It is believed to affect the levels of dopamine and serotonin in the brain. These chemicals are involved in sexual interest and desire. This medication does not improve sexual performance.

This medication may be available under multiple brand names and/or in several different forms. Any specific brand name of this medication may not be available in all of the forms or approved for all of the conditions discussed here. As well, some forms of this medication may not be used for all of the conditions discussed here.

Your doctor may have suggested this medication for conditions other than those listed in these drug information articles. If you have not discussed this with your doctor or are not sure why you are taking this medication, speak to your doctor. Do not stop taking this medication without consulting your doctor.

Do not give this medication to anyone else, even if they have the same symptoms as you do. It can be harmful for people to take this medication if their doctor has not prescribed it.

The recommended dose of this medication is 100 mg taken by mouth, once daily at bedtime.

Many things can affect the dose of medication that a person needs, such as body weight, other medical conditions, and other medications. If your doctor has recommended a dose different from the ones listed here, do not change the way that you are taking the medication without consulting your doctor.

It is important to take this medication exactly as prescribed by your doctor.

If you miss a dose, skip the missed dose and continue with your regular dosing schedule. Do not take a double dose to make up for a missed one. If you are not sure what to do after missing a dose, contact your doctor or pharmacist for advice.

Store this medication at room temperature, protect it from light and moisture, and keep it out of the reach of children.

Each pink, oval, film-coated tablet debossed on one side with "fl100" and blank on the other side contains 100 mg of flibanserin. Nonmedicinal ingredients: croscarmellose sodium, hypromellose, iron oxide red, lactose monohydrate, magnesium stearate, macrogol, microcrystalline cellulose, talc, and titanium dioxide.

Do not take this medication if you:

• are allergic to flibanserin or any ingredients of the medication
• have decreased liver function
• are pregnant
• are breast-feeding
• have low blood pressure and drink alcohol
• are taking any of the following medications:
• aprepitant
• "azole" antifungal medications (e.g., fluconazole, itraconazole, voriconazole)
• carbamazepine
• ciprofloxacin
• cobicistat
• conivaptan
• digoxin
• diltiazem
• dronedarone
• HIV protease inhibitors (e.g., ritonavir, saquinavir)
• macrolide antibiotics (e.g., clarithromycin, erythromycin)
• mifepristone
• certain protein kinase inhibitors (e.g., ceritinib, crizotinib, idelalasib, imatinib, nilotinib, ribociclib)
• phenobarbital
• phenytoin
• rifampin
• St. John's wort
• verapamil

Many medications can cause side effects. A side effect is an unwanted response to a medication when it is taken in normal doses. Side effects can be mild or severe, temporary or permanent.

The side effects listed below are not experienced by everyone who takes this medication. If you are concerned about side effects, discuss the risks and benefits of this medication with your doctor.

The following side effects have been reported by at least 1% of people taking this medication. Many of these side effects can be managed, and some may go away on their own over time.

Contact your doctor if you experience these side effects and they are severe or bothersome. Your pharmacist may be able to advise you on managing side effects.

• abdominal pain
• abnormal dreams
• acne
• anxiety
• constipation
• diarrhea
• dizziness
• dry mouth
• headache
• indigestion
• muscle spasms
• nausea
• night sweats
• rash
• symptoms of sinusitis (e.g., nasal congestion, pressure, pain)
• sleepiness
• spinning sensation
• tiredness
• trouble sleeping (falling asleep or staying asleep)
• vomiting

Although most of the side effects listed below don't happen very often, they could lead to serious problems if you do not seek medical attention.

Check with your doctor as soon as possible if any of the following side effects occur:

• excited mood
• hallucination (seeing or hearing things that aren't there)
• low blood pressure (e.g., blurred vision, dizziness, feeling tired, nausea)
• racing thoughts
• rapid heartbeat (e.g., chest pain, fast pulse, lightheadedness, racing or irregular heartbeat, shortness of breath)
• swelling of the hands or legs
• symptoms of a urinary tract infection (e.g., pain when urinating, urinating more often than usual, low back or flank pain)

Stop taking the medication and seek immediate medical attention if any of the following occur:

• fainting (loss of consciousness)
• signs of a serious allergic reaction (e.g., abdominal cramps, difficulty breathing, nausea and vomiting, or swelling of the face and throat)

Some people may experience side effects other than those listed. Check with your doctor if you notice any symptom that worries you while you are taking this medication.

Before you begin using a medication, be sure to inform your doctor of any medical conditions or allergies you may have, any medications you are taking, whether you are pregnant or breast-feeding, and any other significant facts about your health. These factors may affect how you should use this medication.

Alcohol and other medications that cause drowsiness: Taking flibanserin at the same time as alcohol and other medications that cause drowsiness (e.g., antidepressants, sleeping pills, anxiety medications) can cause increased drowsiness, severe low blood pressure, and fainting. If you have had 1 or 2 standard alcoholic drinks in the evening, wait at least 2 hours before taking your bedtime dose of flibanserin. If you have had 3 or more alcoholic drinks, skip your bedtime dose of flibanserin. If you have low blood pressure you should not drink alcohol while taking flibanserin.

Drowsiness/dizziness: Flibanserin may cause drowsiness or dizziness, affecting your ability to drive or operate machinery. Avoid driving, operating machinery, or performing other potentially hazardous tasks for at least 6 hours after taking this medication. And until you have determined how you are affected by this medication.

Grapefruit and grapefruit juice: Grapefruit, Seville oranges, and their juices interfere with how this medication is broken down and removed from the body. Consuming any of these products while taking flibanserin may cause the medication to build up in the body, causing severe side effects. You should avoid these fruits and their juices while taking flibanserin.

Heart problems: This medication may cause decreased blood pressure, fainting, increased heart rate, or irregular heartbeat. Any of these can cause symptoms of heart problems to worsen. If you have heart disease such as angina, congestive heart failure, or arrhythmia, discuss with your doctor how this medication may affect your medical condition, how your medical condition may affect the dosing and effectiveness of this medication, and whether any special monitoring is needed.

Liver function: Liver disease or reduced liver function may cause this medication to build up in the body, causing side effects. If you have liver problems, discuss with your doctor how this medication may affect your medical condition, how your medical condition may affect the dosing and effectiveness of this medication, and whether any special monitoring is needed. Your doctor may want to test your liver function regularly with blood tests while you are taking this medication.

Low body weight: If you weigh less than 50 kg, you may be more at risk of side effects such as drowsiness, low blood pressure, and fainting. 

Pregnancy: This medication should not be used during pregnancy. If you become pregnant while taking this medication, contact your doctor immediately.

Breast-feeding: It is not known if flibanserin passes into breast milk. If you are breast-feeding and are taking this medication, it may affect your baby. Breastfeeding is not recommended while taking this medication.

Children: This medication is not intended for use by children

Seniors: The safety and effectiveness of this medication have not been determined for women who are older than 60 years of age.

There may be an interaction between flibanserin and any of the following:

• acetylsalicylic acid (ASA)
• alcohol
• aliskiren
• antiarrhythmics (e.g., amiodarone, dronedarone, quinidine)
• anticancer medications (e.g., doxorubicin, etoposide, topotecan, venetoclax)
• antihistamines (e.g., cetirizine, doxylamine, diphenhydramine, hydroxyzine, loratadine)
• antipsychotics (e.g., chlorpromazine, clozapine, haloperidol, olanzapine, quetiapine, risperidone)
• aprepitant
• azelastine
• "azole" antifungals (e.g., itraconazole, ketoconazole, voriconazole)
• benzodiazepines (e.g., alprazolam, diazepam, lorazepam)
• bosentan
• brimonidine
• buspirone
• buprenorphine
• butorphanol
• calcium channel blockers (e.g., amlodipine, diltiazem, nifedipine, verapamil)
• cannabis
• chloral hydrate
• cimetidine
• ciprofloxacin
• clonidine
• cobicistat
• colchicine
• conivaptan
• cyclosporine
• danazol
• dabigatran
• deferasirox
• digoxin
• edoxaban
• elagolix
• entacapone
• esketamine
• estrogens (e.g., conjugated estrogen, estradiol, ethinyl estradiol)
• everolimus
• glecavir and pibrentasvir
• grapefruit juice
• grazoprevir
• HIV non-nucleoside reverse transcriptase inhibitors (NNRTIs; e.g., efavirenz, etravirine, nevirapine)
• HIV protease inhibitors (e.g., atazanavir, indinavir, ritonavir, saquinavir)
• isoniazid
• lemborexant
• lomitapide
• lumacaftor and ivacaftor
• macrolide antibiotics (e.g., clarithromycin, erythromycin)
• methadone
• metoclopramide
• mifepristone
• mirtazapine
• moclobemide
• modafinil
• muscle relaxants (e.g., baclofen, cyclobenzaprine, methocarbamol, orphenadrine)
• nadolol
• naloxegol
• narcotic pain relievers (e.g., codeine, fentanyl, morphine, oxycodone)
• nonsteroidal anti-inflammatory medications (NSAIDs; e.g., diclofenac, ibuprofen, ketorolac, naproxen)
• progestins (e.g., levonorgestrel, medroxyprogesterone, progesterone)
• protein kinase inhibitors (e.g., bosutinib, dasatinib, imatinib, nilotinib)
• proton pump inhibitors (e.g., esomeprazole, omeprazole)
• pramipexole
• rifabutin
• rifampin
• romidepsin
• ropinirole
• St. John's wort
• sarilumab
• scopolamine
• seizure medications (e.g., carbamazepine. clobazam, levetiracetam, phenobarbital, phenytoin, primidone, topiramate, valproic acid, zonisamide)
• selective serotonin reuptake inhibitors (SSRIs; e.g., citalopram, fluoxetine, paroxetine, sertraline)
• sildosin
• siltuximab
• sirolimus
• sodium oxybate
• tacrolimus
• tapentadol
• thalidomide
• tocilizumab
• tolvaptan
• tramadol
• tricyclic antidepressants (e.g., clomipramine, desipramine, imipramine)
• zolpidem
• zopiclone

If you are taking any of these medications, speak with your doctor or pharmacist. Depending on your specific circumstances, your doctor may want you to:

• stop taking one of the medications,
• change one of the medications to another,
• change how you are taking one or both of the medications, or
• leave everything as is.

An interaction between two medications does not always mean that you must stop taking one of them. Speak to your doctor about how any drug interactions are being managed or should be managed.

Medications other than those listed above may interact with this medication. Tell your doctor or prescriber about all prescription, over-the-counter (non-prescription), and herbal medications you are taking. Also tell them about any supplements you take. Since caffeine, alcohol, the nicotine from cigarettes, or street drugs can affect the action of many medications, you should let your prescriber know if you use them.