Fluoxetine is a generic selective serotonin reuptake inhibitor (SSRI), an antidepressant medication that is found in popular brand names like Prozac, Prozac Weekly, and Sarafem. The medication moderates serotonin levels in the brain to treat mood disorders like depression and anxiety. Fluoxetine is also prescribed to help obsessive-compulsive disorder (OCD), binge eating disorder, bulimia, and panic disorder (with or without agoraphobia). Sometimes, it is prescribed to treat premenstrual dysphoric disorder (PMDD); Sarafem was specifically developed to treat this condition.
In rare cases, fluoxetine can be prescribed to treat alcohol use disorder, attention deficit disorder, borderline personality disorder, headaches, sleep disorders like insomnia, Tourette’s syndrome, sexual problems, phobias, post-traumatic stress disorder (PTSD), and other mental illnesses that benefit from adjustments in how serotonin interacts with the brain.
How Fluoxetine Works
SSRIs like fluoxetine work by preventing serotonin from being reabsorbed rapidly after it is released. When serotonin is absorbed too fast, it is not able to help neurons communicate as well; with fewer signals moving between neurons, mood and physical energy can be low. However, an SSRI allows serotonin to remain in the synapses – the spaces between neurons – for longer, helping neurons communicate with each other. This elevates mood and improves energy.
Doses are found in tablet, capsule, and liquid form. Sizes of fluoxetine doses include 10 mg, 20 mg, and 40 mg; Sarafem specifically is found in 10 mg, 15 mg, and 20 mg forms.
Dosing depends largely on which condition fluoxetine has been prescribed to treat. For example, Sarafem may be taken once per day consistently, or it could be taken for specific days in the woman’s menstrual cycle. Prozac Weekly, which comes in 90 mg, is only taken once per week, but lower-dose versions of fluoxetine are taken once per day. Fluoxetine is always taken orally.
Like other SSRIs, fluoxetine needs a few weeks to fully work on brain chemistry. The medication should be taken consistently for 4-6 weeks before it is in full effect.
When fluoxetine works well, the medication elevates, then stabilizes mood. Mood swings and irritability can still occur, but they are less likely to occur, as are other depression-related symptoms like feeling guilty without cause, feeling sad, sleeping too much, and feeling hopeless.
Like other psychiatric medications, SSRIs like fluoxetine can cause side effects. These are rare in most people who take the medication, although experiencing side effects could be an indication that the dose is too high and should be adjusted by the person’s physician or therapist.
Side effects include:
- Sore throat
- Dry mouth
- Physical weakness
- Trembling or shaking that is involuntary
- Changes to appetite or weight
- Changes to sex drive
- Increased sweating
Weight gain is a common side effect from taking fluoxetine. While this is typically not a dangerous side effect for many people, it can reduce self-image and sense of self-worth. For some people, weight-related diseases like diabetes or heart disease can occur, so it is important to work with a medical professional to moderate weight gain if it occurs.
More serious side effects, like an allergic reaction, can indicate a serious, negative interaction with the medication. Call 911 for emergency medical treatment if these side effects occur:
- High fever
- Joint pain
- Swelling to the face, lips, throat, tongue, eyes, hands, feet, or lower legs
- Trouble breathing or swallowing
- Rapid or irregular heartbeat
- High blood pressure
- Extreme muscle stiffness
- Aggression or violence
People under the age of 24 years old are also more likely to experience suicidal thoughts or actions while taking fluoxetine.
If a person experiences these thoughts while taking fluoxetine, they should contact their prescribing physician or therapist immediately.
Using Fluoxetine for a Long Time
There are no severe long-term effects for adults who take fluoxetine, and there are few studies on the side effects on children who take fluoxetine. Taking fluoxetine or other SSRIs while pregnant has a less than 1 percent chance of causing birth defects to the fetus, so a woman who is pregnant or who plans to become pregnant should speak to her doctor about taking this medication.
Fluoxetine may also exacerbate some pre-existing health conditions, particularly heart problems. However, the medication has not been linked to triggering these problems. This medication is known to lead to physical dependence; although this is not the same as addiction, the condition can cause withdrawal symptoms.
Is Fluoxetine Addictive?
Fluoxetine and other SSRIs are not considered to be addictive, in part because they do not act quickly on brain chemistry to induce euphoria, or high. They take weeks to fully settle into the system; in fact, Prozac is sometimes prescribed to treat alcohol use disorder after detox. The medication reduces cravings, and stabilizes mood, so the person is less likely to drink to self-medicate a mood disorder. While some people may attempt to abuse fluoxetine, these individuals typically have a history of substance abuse problems, or polydrug abuse issues, and are at greater risk of struggling with any prescription medication.
Withdrawal Symptoms from Fluoxetine
While fluoxetine does not induce addiction, it can lead to physical dependence. If a person stops taking fluoxetine, Prozac, or Sarafem suddenly, they may experience withdrawal symptoms, including:
- Chest pain
- Rapid heart rate
- Muscle pain
- Nausea or vomiting
- Cold- or flu-like symptoms
- Difficulty falling or staying asleep
- Shaking or trembling
- Unusual physical weakness
- Vision changes
- Rebound depression or anxiety
To avoid withdrawal symptoms, the person should work with their doctor or psychiatrist to taper the medication, so their body no longer needs it.
When a person overdoses on fluoxetine, it is typically because they have accidentally combined antidepressant medications, especially more potent antidepressants like tricyclics or MAO inhibitors. It is very important to allow at least two weeks for MAO inhibitors to leave the body before beginning a new antidepressant, as the medications can otherwise lead to a type of overdose called serotonin syndrome.
Symptoms of an overdose involving fluoxetine include:
- Difficulty focusing the eyes
- Abnormal walking or gait
- Extreme confusion
- Lack of response
- Shaking or tremors
- An inability to wake up
- Unusual or paradoxical excitement
- Rapid or irregular heartbeat
- Nausea and vomiting
If fluoxetine does not work, there are other SSRI medications that may work better to treat any of the same disorders. SSRIs are considered the best option for treating depression, when they are used in combination with talk therapy; increasingly, SSRIs are used instead of benzodiazepines or other anti-anxiety medications, in combination with therapy, to treat anxiety disorders.
Psychiatric medications are not designed to function alone. It is important for a person who has been prescribed an SSRI to treat a diagnosed mental health condition, such as depression, anxiety, OCD, PTSD, or another condition, to find a therapist to work with.
Exercise and healthier dietary choices can help adjust mood as well. For some people, these lifestyle changes may work in place of medication; for other people, who have chronic mental health conditions, they can enhance the benefits of medication and therapy. It is important for each individual to evaluate their needs, with the help of a physician and therapist.
People who struggle with panic attacks or the sudden onset of panic may benefit from benzodiazepines, such as Valium, Klonopin, or Xanax. These medications are very habit-forming, however, and should not be taken consistently for more than two weeks. They are designed to treat the worst symptoms of anxiety, so the person can relax and get the therapeutic help they need. The individual should stop taking them once their panic has decreased. In many cases, benzodiazepines are prescribed as needed.
Fluoxetine’s Use in Addiction Treatment
Fluoxetine can be used to reduce the risk of relapse in people who have recovered from alcohol use disorder, and it may be prescribed during detox or a rehabilitation program to help people who suffer a mood disorder that led to addiction. However, it is only one tool in a much larger toolbox; rehabilitation programs offer many options, including therapy and social groups, that help people overcome addictions.