What are the side effects of Prozac for women?

Prozac (fluoxetine) is a selective serotonin reuptake inhibitor (SSRI) antidepressant approved by the U.S. Food and Drug Administration (FDA) to treat mental health conditions such as major depressive disorder, panic disorder, obsessive-compulsive disorder (OCD), and binge eating disorder. It works by increasing serotonin levels, a natural feel-good hormone, in the brain.

Like most prescription medications, Prozac can have side effects, such as suppressed appetite, nausea, diarrhea, dry mouth, drowsiness, and trouble sleeping. However, some side effects may differ based on the patient’s sex. For example, men may experience erectile dysfunction while women may see decreased libido. Read on to learn more about how this medication affects women.

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Fluoxetine side effects in females

In the process of treating the condition it’s prescribed for, fluoxetine (known by its brand name Prozac) may also trigger some unwanted side effects. Common side effects of Prozac include gastrointestinal issues like nausea, diarrhea, and heartburn; trouble sleeping; and headaches.

However, there are side effects that primarily affect women. They include loss of appetite, weight loss, and sexual dysfunction, such as loss of sexual desire, weakened arousal and lubrication, delayed orgasm, and anorgasmia.

“It is possible for individuals to notice some side effects within the first few days of starting fluoxetine as the body is getting used to the medication,” says Frances Javier, MD, psychiatrist and medical director at Neuro Wellness Spa. Some of these side effects will disappear with time, though. 

In some people, Prozac may also trigger serious side effects, such as swelling on the face, lips, eyes, ankles, or lower legs, difficulty breathing, irregular heartbeat, seizures, hallucinations, agitation, bleeding, and lack of coordination. Fluoxetine may also cause narrow-angle glaucoma (fluid buildup in the eye). If you experience any of these, seek medical advice from a healthcare professional and report any uncommon or worsening adverse effects.

Impact of fluoxetine on female hormonal balance

About 80% of women taking SSRIs have reported sexual dysfunction. According to a 2022 animal study, all SSRIs—including fluoxetine—showed the ability to affect the production of hormones including estrogen, progesterone, and androgens when tested in the laboratory. 

This very small animal study demonstrated that when mice were given high doses of fluoxetine their reproductive cycles were altered. At high doses, fluoxetine was associated with irregular cycles, fewer corpus luteum (involved in progesterone production in early pregnancy), decreased follicle development, and reduced ovulation. The study also found an association between increased estrogen concentration and taking fluoxetine—which may affect other reproductive hormones including gonadotropin hormone-releasing hormone (controls the production of sex hormones), follicle-stimulating hormone (plays a role in sexual development and reproduction), and luteinizing hormone (controls the menstrual cycle in women). 

The researchers recommended caution for women and girls of reproductive age using fluoxetine. However, because this research has only been performed in animals, it’s uncertain if the same conclusions would apply to human subjects. 

“The vast majority of findings in animal studies do not translate to humans,” says Bruce Bassi, MD, the medical director at TelepsychHealth. “I would not put a lot of weight on a study that looked at such a small sample size (6/7 per group).” 

In other words, more evidence is needed to support any conclusions about how fluoxetine affects hormonal balance in human females.

Long-term fluoxetine side effects in women

When women are on fluoxetine for six to 10 years or longer, they have reported long-term side effects, including:

• Restlessness
• Tension
• Agitation
• Sleep disturbances
• Low sex drive (which may persist even after discontinuation)

They also report low estrogen—which can trigger or contribute to painful vaginal intercourse, hot flashes, irregular periods, and more—but the data on fluoxetine’s impact on estrogen is conflicting. 

“Some data supports that Prozac can decrease estrogen levels, but it is unclear why,” Dr. Bassi says. “The evidence is conflicting, as other studies showed an increase.”

According to the medication insert, when discontinuing use of Prozac, whether they’ve taken it long-term or not, women should do so under the supervision of a healthcare provider. “A gradual reduction in the dose rather than abrupt cessation is recommended whenever possible,” says Alisha Reed,  Pharm.D., a pharmacist based in New Orleans, Louisiana. 

Patients should be monitored for potential withdrawal symptoms or worsening mood. These symptoms include dysphoric mood, irritability, agitation, dizziness, sensory disturbances (e.g., electric shock sensations), anxiety, confusion, headache, lethargy, emotional lability, insomnia, and hypomania. “While these reactions are generally self-limiting,” Dr. Reed says, “there have been reports of serious discontinuation symptoms.” 

How long do fluoxetine side effects last?

Some side effects are temporary and may disappear after your body adjusts to the medication. For instance, according to one study, the suppression of appetite experienced in the first two to three months of taking fluoxetine slowly goes away with time, such that in six months, the person’s appetite returns to normal. 

However, Dr. Javier says that adjusting to fluoxetine is a unique experience for each individual. “Some [people] may notice some mild improvement in symptoms as early as two weeks, such as changes in sleep, appetite, and energy,” she says. “However, a more common timeline is around four to eight weeks, especially for symptoms of low mood, lack of motivation, and lack of interest in activities.” 

How to treat side effects of fluoxetine in females

One common side effect of fluoxetine for women is sexual dysfunction. If you suspect that fluoxetine is affecting your sex life, do not stop the medication without informing your healthcare provider, who may recommend reducing the dose or changing medications. Sometimes lowering the dose may be enough to alleviate the sexual side effects. You can also try planning sexual activity for moments when the effects of the medication are at their lowest. Another option is to work with a sex therapist or switch to a different drug (only if directed by your healthcare provider).

Some severe side effects of Prozac will demand immediate medical attention. It is a good idea to see your healthcare provider for side effects including irregularity in the menstrual cycle, unexplained weight loss, or weight gain. If you’re experiencing allergic reactions to the medication, get medical attention urgently. You should also call your doctor immediately if you experience the following: feelings of euphoria, bleeding gums, unexplained bruises, bloody sputum, or blood in your urine, stool, and vomit. If you experience suicidal thoughts, seek emergency help immediately or call 988.

Some side effects may go away as your body gets used to the drug; however, it is a good idea to speak with your healthcare provider about new symptoms while using this medication.

How to avoid fluoxetine side effects

Like most prescription drugs, fluoxetine can trigger unwanted side effects. There are a number of strategies you can try to minimize the risk of fluoxetine side effects: 

• Take fluoxetine at a certain time of day; this time will depend on the side effects you experience. For example, taking it in the morning can minimize the risk of insomnia. Then, take the medication at the same time every day.
• Work with your provider to find the right dose. If you’re having side effects, you may need a higher or lower dosage. Fluoxetine can be taken at doses as low as 20 mg daily. 
• Tell your provider and pharmacist about all other medications and supplements you take, which will help you avoid drug interactions. Prozac should not be taken with antidepressants such as monoamine oxidase inhibitors (MAOIs) or thioridazine serotonergic drugs (such as triptans, tricyclic antidepressants, and St. John’s Wort). Combining certain medications increases the risk of serotonin syndrome.
• Inform your healthcare provider about other medical conditions you have, such as heart failure, high blood pressure, bleeding problems, stroke, diabetes, seizures, and liver or kidney disease. You should also let them know if you have low sodium, potassium, or magnesium levels.

Do not stop taking fluoxetine without your healthcare provider’s advice. If you are discontinuing the medication, your provider may reduce your dosage gradually to reduce the risk of you experiencing withdrawal symptoms. It’s important to stay in contact with your provider so they can help you navigate and alleviate any adverse effects of Prozac.