Short answer: Both treat acquired, generalized hypoactive sexual desire disorder (HSDD) in women.12 Addyi is a 100 mg tablet taken every night at bedtime and is approved for women under 65. Vyleesi is a 1.75 mg shot under the skin, used as needed at least 45 minutes before sex, for premenopausal women. Only Addyi has a boxed warning, on fainting with alcohol. Neither label reports a trial against the other.
| Addyi | Vyleesi | |
|---|---|---|
| Drug and form | Flibanserin 100 mg tablet1 | Bremelanotide 1.75 mg prefilled autoinjector2 |
| Approved for | Women under 65 with acquired, generalized HSDD; not for men or to enhance sexual performance1 | Premenopausal women with acquired, generalized HSDD; not for postmenopausal women or men, or to enhance sexual performance2 |
| How used | Once daily at bedtime, every day1 | As needed, at least 45 minutes before expected sexual activity; no more than one dose in 24 hours, and more than 8 a month is not recommended2 |
| If there is no improvement | Stopped after 8 weeks1 | Stopped after 8 weeks2 |
| Most common side effects in label trials | Dizziness 11.4% vs 2.2% on placebo, sleepiness 11.2% vs 2.9%, nausea 10.4% vs 3.9%1 | Nausea 40.0% vs 1.3% on placebo, flushing 20.3% vs 0.3%, headache 11.3% vs 1.9%2 |
| Stopped because of side effects | 13% vs 6% on placebo1 | 18% vs 2% on placebo2 |
| Boxed warning | Low blood pressure and fainting with alcohol, moderate or strong CYP3A4 inhibitors, or liver impairment1 | None2 |
Taking Addyi and alcohol close together raises the risk of severe low blood pressure and fainting. The boxed warning says to wait at least two hours after one or two standard drinks before the bedtime dose, to skip that night's dose after three or more drinks, and not to drink after the dose until the next day.1 In a study of Addyi taken at the same time as about two drinks, 4 of 23 healthy people (17%) had low blood pressure or fainting that needed treatment. Moderate or strong CYP3A4 inhibitors, including grapefruit juice, and any degree of liver impairment are also contraindicated for the same reason.1
Addyi can cause sleepiness, and the label says to avoid driving or using machinery until at least 6 hours after a dose. It is taken at bedtime because daytime dosing raises the risk of low blood pressure, fainting and sleepiness.1 Each Vyleesi dose briefly raises blood pressure, by up to 6 mmHg systolic, with a peak 2 to 4 hours after the dose, so it is not used with uncontrolled high blood pressure or known heart disease. Its label also lists skin darkening on the face, gums or breasts (1% with up to 8 doses a month), and nausea that was most common after the first dose: 21% then, about 3% after later doses.2 These numbers come from separate trials with different people, lengths and methods, so they are not a head-to-head comparison.
Which, if either, fits is for your prescriber. More detail: Addyi side effects, Vyleesi side effects, the Addyi and Vyleesi dosing schedules, and the Addyi missed-dose page.