Disclaimer: None of the information in this article constitutes medical advice, and is just the opinion of the writer(s). We recommend that patients follow their doctor’s guidance in regard to prescription medication.
Fluoxetine, also referred to as fluoxetine hydrochloride or fluoxetine HCL for short, is a prescription drug approved by the FDA for the treatment of depression. It’s the generic version of the drug Prozac, as we explained in our Prozac reviews article.
But is fluoxetine as effective as Prozac? How much can it reduce depression scores? Does it cause concerning side effects? And does it cause worse side effects in women than men?
In this article we’ll answer all of these questions and more, as we review clinical studies on fluoxetine to determine if it's effective for the treatment of depression.
We'll discuss potential side effects, explain whether the drug causes worse side effects in women than men, and share patient ratings of fluoxetine.
We'll also explain how the drug works in the body, and whether it's more or less effective than a similar antidepressant called fluvoxamine.
Does Fluoxetine Reduce Depression?
Fluoxetine has been studied in hundreds of clinical trials involving depressed patients.
A 2004 medical review documented that fluoxetine reduced depression severity after just one week of treatment, and decreased depression scores by an average of 38% after three weeks of treatment.
This review surveyed data from nearly 10,000 patients.
A clinical trial on fluoxetine published in the BMC Psychiatry journal examined the drug's efficacy for treating major depressive disorder (MDD) in postmenopausal women.
After eight weeks of treatment, fluoxetine reduced depression scores by an average of around 50%. There was clinically significant improvement after just one week.
An extensive meta-study on the effectiveness of 21 antidepressants found that fluoxetine was effective on average, but was one of the least effective medications studied.
Overall, we will conclude that fluoxetine is effective for the treatment of depression, which is unsurprising given that it's approved for that indication by the FDA.
However, it appears based on clinical trials cited in this article that other prescription antidepressants may be more effective.
Does Fluoxetine Cause Side Effects?
Fluoxetine does cause side effects in some patients.
A meta-study on the side effects of fluoxetine found that the most common side effects were nausea, nervousness and insomnia.
The study authors reported that these side effects were more common in patients taking fluoxetine than those taking a different class of antidepressants called tricyclic antidepressants.
This suggests that patients with anxiety or sleep disorders may wish to speak with their doctor about tricyclic antidepressants instead of fluoxetine.
Fluoxetine's FDA label indicates that the drug may increase risk of suicidal thoughts and behaviors in young adults, adolescents and children.
Increased risk of suicidality shouldn't affect most fluoxetine users; it’s a rare side effect. However, this side effect is so concerning that it may benefit young adult patients or guardians of adolescents to speak with their doctor about alternative antidepressants that do not confer this risk.
The FDA reserves black box warnings for side effects that may be life-threatening, and this is the most severe category of warning issued by the FDA.
Real People Try Fluoxetine
A YouTube creator named "The Better Side of Life" shared her experience after one year of using fluoxetine:
A TikTok creator named Vikki Williams shares some side effects she experienced from fluoxetine:
@vikkiwilliams Finally having a medication switch #fluoxetine #weightgain #sideeffects #antidepressants #numb #exhaustion #bpd #eupd ♬ original sound - Kyle & Jackie O
Do Women Experience Worse Side Effects?
Women are often curious if there are any drug-specific side effects for them, given that some antidepressants are documented to cause side effects in women specifically.
A medical review published in the Journal of Sex & Marital Therapy found that fewer women (13.4%) reported a worsening of sexual function on fluoxetine than men (17.4%).
We are unable to locate any other medical studies documenting a sex-based difference in fluoxetine side effects, so we will conclude that there does not appear to be any side effects of this drug specific to women, and women may even respond better to the drug than men based on early research.
Patients (of either sex) experiencing sexual dysfunction may benefit from speaking with their doctor about antidepressant medications without sexual side effects.
Is the Brand-Name Version Better?
Prozac is the branded version of fluoxetine.
We would recommend that patients speak with their doctor about fluoxetine rather than Prozac.
Since both drugs contain the same active chemical compound, it seems logical to take the generic version which can be cheaper. This is an especially important consideration for patients without health insurance.
A medical review compared the efficacy and safety of branded and generic drugs, analyzing data from over 1 million patients. Generic drugs were found to be just as effective as brand name drugs on average. This suggests that generic fluoxetine is as effective as Prozac.
The retail price of Prozac is currently around $450 at the time of updating this article, according to GoodRx.
The retail price of fluoxetine is currently under $7 at Cost Plus Drugs.
Patients Rate Fluoxetine
Drugs.com is a website that allows prescription medication patients to rate and review the drugs they're taking.
We cannot verify the accuracy or authenticity of any reviews on this site.
Fluoxetine currently has an average rating of 6.9/10 on Drugs.com for treating depression.
A top positive review of the drug comes from a user named “READTHISPLEASE” who gave the drug a 10/10 rating, and claims it caused a significant improvement in their mental state:
“ONE YEAR AGO I WAS YOU READING THIS COMMENTS THINKING IT WOULD NEVER GET BETTER. WELL IT GOT PRETTY DAMN BETTER. (: God bless whoever is reading this.”
A top negative review of fluoxetine is written by a user called “Mcano” who gave the drug a 1/10 rating, and claims it caused weight gain:
“Caused uncontrollable massive weight gain just like the atypical antipsychotics do (129 to 185 in 3 months!!! Eating same diet. Robot emotions. Hair loss. And suddenly...good old diabetes 2.”
Can You Drink on Fluoxetine?
Fluoxetine's label indicates that users of the drug should avoid alcohol entirely.
There’s also some interesting clinical research showing fluoxetine may decrease the desire to drink.
A clinical trial in an alcoholic patient population found that fluoxetine decreased the desire to drink.
Trial participants were presented with a variety of alcoholic beverages, and those taking fluoxetine showed a decreased desire to drink any of them compared to the placebo group. Fluoxetine at a dose of 60 milligrams (mg) per day decreased alcoholic drinks consumed by around 50%.
These results were mirrored in a separate clinical trial which found that depressed alcoholic patients taking fluoxetine experienced improvement in depression scores and also decreased their alcohol intake throughout the course of the trial.
Fluoxetine appears to have a negative interaction with alcohol according to the drug's manufacturer, so it's imperative that patients have an honest conversation with their doctor about their alcohol intake and whether they will be able to avoid alcohol entirely while using this drug.
The good news is that fluoxetine appears to decrease the desire to drink, so for patients who are able to avoid alcohol during their first few weeks on the medication, they may lose the desire to drink entirely which can benefit health.
Fluoxetine vs. Fluvoxamine
Fluvoxamine is another generic antidepressant, so patients are often curious about which drug is more safe and effective.
A 2003 clinical trial compared the effectiveness of these two drugs for treating major depression.
Depressed patients were given one of the two drugs for 6 weeks, and researchers tracked changes in their depression scores using the Hamilton Depression Rating Scale (HAMD), which is a clinical tool for depression tracking.
The study authors found that there was no difference in efficacy. Both drugs decreased depression to a statistically significant degree. Fluvoxamine required a shorter duration of time to be effective, so it may be a better option for patients suffering from a severe, acute depressive episode.
Based on the available research, we would recommend that patients speak with their doctor about fluvoxamine instead of fluoxetine.
Our Mental Wellness Picks
Brightside Health is our top overall mental wellness pick.
Brightside is an online therapy and medication platform that connects patients with licensed therapists and psychiatrists from the comfort of their home.
A medical review published in the Clinical Psychology & Psychotherapy journal found that online therapy was equally effective to in-person therapy for treating depression, anxiety and PTSD.
Mindbloom is our top alternative mental wellness pick.
Mindbloom offers ketamine therapy, and over 88% of patients experienced relief of anxiety and depression symptoms in a clinical trial on the brand.
How Does Fluoxetine Work?
Fluoxetine is a member of a class of pharmaceutical drugs called selective serotonin reuptake inhibitors (SSRI).
This is the most common type of antidepressant.
As we documented in our Celexa reviews article on another popular SSRI drug, this class of drugs minimizes the reuptake of serotonin in the brain.
This artificially increases circulating serotonin levels. Serotonin is a neurotransmitter that influences mood and depression, so increasing its levels may normalize brain function in patients suffering from depression.
Researchers still haven’t conclusively shown that low levels of serotonin in the brain are the cause of depression; we just know that this type of drug is effective on average in depressed patients.
Fluoxetine Dosage
A 2022 medical review documents the dosing range for fluoxetine.
Fluoxetine dosage typically starts at 20 mg per day. It can be broken into smaller doses taken throughout the day to minimize side effects.
A patient prone to anxiety may start on a 10 mg dose in the morning and a 10 mg dose in the evening, rather than one single 20 mg dose, to decrease the risk of acute side effects.
Fluoxetine has been studied, and proven safe, at daily doses up to 80 mg according to the above-linked medical review.
Typically, a doctor will increase dosage up to the safety limit if the patient isn’t responding to treatment. If a patient isn’t experiencing any benefit at 80 mg per day, they can speak with their doctor about alternative options.
