What You Should Know About Addyi Side Effects Before Starting

Starting a new medication always comes with questions — especially when that medication has a boxed warning on the label. If you're considering Addyi (Flibanserin) for hypoactive sexual desire disorder (HSDD), understanding the side effects upfront will help you feel more prepared and know what's worth a call to your doctor.

The good news: most side effects are mild and manageable. The not-so-good news: there are a few serious risks you need to take seriously, especially around alcohol and certain medications.

Here's a straightforward breakdown of what to expect.

What Is Addyi? A Quick Refresher

Addyi is the only FDA-approved daily pill for HSDD in women under 65. It works by adjusting brain chemistry — specifically acting on serotonin, dopamine, and norepinephrine — to help restore sexual desire. For a deeper dive, read our guide on what Addyi is and how it's used.

You take one 100 mg tablet at bedtime each night. The bedtime timing isn't just a suggestion — it's a safety measure designed to reduce side effects.

Common Side Effects of Addyi

These are the side effects most women experience. They're usually mild and tend to improve over the first few weeks as your body adjusts.

Dizziness

Dizziness is the most frequently reported side effect. It's one of the main reasons Addyi must be taken at bedtime — if you're sleeping through the peak of the medication's effect, you're less likely to notice it. If dizziness is bothersome during the day, mention it to your doctor.

Sleepiness (Somnolence)

Many women feel more sleepy than usual, particularly in the first couple of weeks. This can actually work in your favor since you're taking it at bedtime. However, be cautious about morning grogginess. Don't drive or operate heavy machinery until you know how Addyi affects you.

Nausea

Some women experience nausea, especially in the first few days. Taking Addyi at bedtime helps here too, since you may sleep through the nausea. If it persists, talk to your doctor.

Fatigue

A general feeling of tiredness can occur. This is different from sleepiness — it's more of a low-energy feeling during the day. It usually improves within a few weeks.

Insomnia

This might seem contradictory given the sleepiness side effect, but some women experience difficulty staying asleep or getting quality sleep. If this happens, let your provider know.

Dry Mouth

A less common but reported side effect. Staying hydrated and using sugar-free lozenges can help.

Serious Side Effects and the Boxed Warning

Addyi carries an FDA boxed warning — the most serious type of warning — for three specific situations. These aren't theoretical risks; they're documented dangers that require strict precautions.

Severe Low Blood Pressure (Hypotension)

Addyi can cause a significant drop in blood pressure, leading to lightheadedness, weakness, or fainting. This risk is dramatically increased in two situations:

• Drinking alcohol: Combining Addyi with alcohol is the number one safety concern. Even moderate drinking can trigger a dangerous blood pressure drop. The FDA recommends waiting at least 2 hours after consuming 1–2 alcoholic drinks before taking Addyi. If you've had 3 or more drinks, skip your dose entirely that night.
• Taking certain other medications: Moderate or strong CYP3A4 inhibitors (a class of drugs that affect how your liver processes Addyi) can increase Flibanserin levels in your blood to dangerous levels. This includes common medications like Fluconazole (for yeast infections), certain antibiotics, and some heart medications. See our complete guide on Addyi drug interactions.

Fainting (Syncope)

Fainting episodes can occur, especially in the risky scenarios described above. If you faint while taking Addyi — even once — contact your doctor right away. Fainting can lead to falls and injuries, which is the downstream risk that makes this side effect particularly concerning.

Central Nervous System (CNS) Depression

Addyi can amplify the sedating effects of other CNS depressants, including benzodiazepines, opioids, and even over-the-counter antihistamines like Diphenhydramine (Benadryl). This combination can cause extreme drowsiness, impaired coordination, and dangerously low blood pressure.

Side Effects in Specific Populations

Women Over 65

Addyi is not indicated for women over 65. Clinical trials did not include enough older women to establish safety and efficacy in this age group.

Women with Liver Problems

Addyi is contraindicated — meaning it should absolutely not be used — in women with any degree of hepatic (liver) impairment. The liver processes Flibanserin, and impaired liver function causes the drug to build up to dangerous levels.

Pregnant or Breastfeeding Women

Addyi has not been studied in pregnant or breastfeeding women. If you become pregnant while taking Addyi, stop the medication and contact your doctor.

How to Manage Side Effects

Most side effects can be managed with simple strategies:

• Always take Addyi at bedtime. This is the single most important thing you can do to minimize side effects. It reduces your exposure to dizziness, sleepiness, and nausea during waking hours.
• Avoid alcohol entirely if possible. If you do drink, follow the strict guidelines: wait 2+ hours after 1–2 drinks, skip the dose after 3+ drinks.
• Give it time. Many side effects improve after 2–4 weeks as your body adjusts. Don't give up too early — but also don't ignore symptoms that are getting worse.
• Review all medications with your doctor. Before starting Addyi, make sure your provider knows every medication, supplement, and OTC product you take. Some interactions aren't obvious. Our drug interactions guide covers the major ones.
• Stay hydrated. Drinking plenty of water can help with dry mouth, dizziness, and general well-being.
• Get up slowly. If you wake during the night or first thing in the morning, get up slowly to reduce the chance of a blood pressure drop.

When to Call Your Doctor

Contact your healthcare provider if you experience any of the following:

• Fainting or near-fainting episodes
• Dizziness that doesn't improve after a few weeks
• Severe or persistent nausea
• Extreme drowsiness that affects your daily life or ability to drive
• Any side effect that feels concerning or unusual

Go to the emergency room if you faint and hit your head, if you can't be woken up, or if your blood pressure drops dangerously low.

Final Thoughts

Addyi's side effects are real but manageable for most women. The most important rules are simple: take it at bedtime, avoid alcohol, and make sure your other medications don't interact with it.

If you're still weighing whether Addyi is right for you, read our overview of what Addyi is and how it works. And when you're ready to fill your prescription, Medfinder can help you find a pharmacy that has it in stock.