Prozac side effects can negatively influence a person’s sleep patterns, mood, weight, sexual activity, and gastrointestinal health. Less common, but more severe effects, can include abnormal bleeding, suicidal ideation (in younger patients), allergic reactions (including rash, swelling and trouble breathing), and serotonin syndrome (presents as shaking, fever or sweating, fast or irregular heartbeat and loss of muscle function).1
What Is Prozac?
Prozac, or fluoxetine, is a medication commonly used to treat depression or obsessive compulsive disorder (OCD) in adults and occasionally children. In some cases, Prozac may also be prescribed in the treatment of panic disorder and premenstrual dysphoric disorder (PMDD).2 Prozac is an SSRI (selective serotonin uptake inhibitor) that works by increasing a person’s serotonin levels, and is often one of the first medications prescribed.4 It helps one manage associated with depression such as feelings of sadness or worthlessness, decreased energy, loss of interests, loss of appetite, and difficulty sleeping.3
Common Side Effects of Prozac
Prozac typically causes changes in appetite and sleep, especially at the beginning of treatment. It is important to consult your doctor regarding side effects, as they can help you minimize adverse reactions.Oftentimes, they may instruct you to dose at a certain time of the day, or recommend healthy ways to cope with unwanted side effects. Some initial reactions may decrease or go away with time as your body gets used to the new treatment.5
Typically, Prozac requires 4 to 6 weeks to take full effect. After this period, you should notice an improvement of symptoms and a positive increase in mood.4
Common side effects of Prozac include the following:2
- Nausea
- Diarrhea
- Indigestion
- Weakness
- Feeling tired
- Abnormal dreams
- Trouble sleeping or insomnia
- Decreased appetite
- Nervousness
- Rash, watery nasal discharge
- Sweating
- Tremor (shakes)
- Hot flashes
- Problems with orgasm
- Decreased sex drive
- Difficulty maintaining an erection
Severe Side Effects of Prozac
While serious side effects of Prozac are rare, they most often occur after someone first starts or increases a Prozac dosage. They may also occur if other certain prescriptions are taken alongside Prozac. Your doctor may run tests before and during treatment, if certain risk factors for extreme reactions are present.4
Severe side effects of Prozac may include the following:
- Suicidal ideations
- Rash, hives, blisters, or itching
- Joint pain
- Swelling
- Difficulty breathing or swallowing
- Increased agitation
- Fevers, sweating, or shivering
- Confusion or loss of coordination
- Hallucinations
- Nausea, vomiting, or diarrhea
- Irregular heartbeat
- Seizures
- Abnormal bleeding
Abuse & Dependence
When used correctly, Prozac has been proven to improve symptoms of various mental health conditions. As your body adjusts to your dosage, the drug will work well within your system. However, taking more than you are prescribed can be detrimental to your health. A large dose can lead to a myriad of issues including sudden cardiovascular problems, hallucinations, hyperthermia, coma, vomiting, diarrhea, and loss of bodily control.2
If you feel that you have become or are at risk of becoming physically dependent on Prozac, consult your physician about how to safely terminate your dosage. Quitting abruptly can be dangerous and unpleasant.8 Fluoxetine is not a medication that is associated with misuse or addiction.
Prozac Long Term Side Effects
Long term side effects of taking Prozac are rare, and generally occur only in specific populations. Reports show that Prozac may cause an increased risk of bone fractures and bleeding in some patients, along with an activation of mania or hypomania symptoms. You can speak with your doctor about ways to decrease the likelihood of experiencing these effects.2
Prozac Side Effects in Women
In women, many side effects of Prozac resemble the common symptoms of menopause.
However, Prozac has not been found to affect fertility or interact with any oral birth control medications.2 If you are premenopausal or menopausal, you should be sure to alert your care provider of any questionable reactions.
Side effects of Prozac in women may include the following:1
- Decreased sex drive
- Delayed or absent orgasm
- GI Distress
- Weight gain
Pregnant & Breastfeeding Women
Prozac has been shown to cross the placenta during pregnancy and be excreted through breast milk. When mothers take Prozac during their third trimester, the risk of newborns presenting withdrawal symptoms upon birth increases.2,7 It is important to talk with your doctor if you are considering becoming pregnant or currently breastfeeding. Other prescriptions for treating depression may be better suited and safer, for both you and your baby.
Prozac Side Effects in Men
Men who are prescribed Prozac may notice a decrease in sexual functions. This can be cause for concern for some, but consulting a doctor regarding these side effects may be helpful. There are other medications that can be safely introduced into your treatment plan to address any sexual dysfunctions.6
Side effects of Prozac in men may include the following:1
- Decreased sex drive
- Inability to get or keep an erection
- Delayed or absent ejaculation
How Quickly Do Prozac Side Effects Start?
As Prozac builds up in your body, side effects will present at different times. The most common initial side effects are dry mouth, nausea, headaches, and trouble sleeping; these will most likely subside with time.5 Weight changes and sexual dysfunctions often occur after weeks or months of therapy.2 However, not everyone will have the same experience with Prozac, and side effects can occur at any time.
Do Prozac Side Effects Go Away?
Many negative side effects of Prozac will dissipate within a few weeks. Additionally, other prescriptions may be utilized to help subdue reactions such as gastrointestinal issues or headaches. With your doctor’s guidance, you can decrease the likelihood of sleep disturbances by changing your dosage schedule.5 If side effects persist or interfere with your life significantly, your care team will facilitate stopping Prozac or recommend switching to a new medication. Negative side effects can continue or worsen if Prozac treatment is not stopped correctly.
Warnings & Interactions to Avoid While Taking Prozac
Certain medications can affect or cease functioning of Prozac within your body, or heighten the severity of its associated side effects. Making sure you know what to avoid when using Prozac will help eliminate the risk of these occurrences.2,5
Substances to avoid while taking Prozac include:
- Monoamine Oxidase Inhibitors or MAOIs
- Warfarin
- St. John’s Wort
- Lithium
- Thioridazine
- Tramadol
- Alcohol
- Other non-prescription medications
- Recreational drugs
- Other antidepressant medications classified as SSRIs or SNRIs
- Migraine medications that are part of the triptans drug class
Prozac Withdrawal
While the risk is relatively low, symptoms of withdrawal can occur if you abruptly stop taking or significantly lower your dose of Prozac.8 Both actions should always be done with the supervision of your doctor. You will likely be directed to slowly lower the dose over a period of time to reduce potential effects.9
Questions to Ask Your Health Team About Prozac Side Effects
Communicating your concerns with a provider before and after starting Prozac is important. Being open and honest with your care team allows them to create a treatment plan that will be both effective and helpful for you. Be sure to alert your doctor about any allergies you may have or any prescription and non prescription drugs you take.10
Questions to ask your care team about Prozac include:
- What time of day should I take my medication?
- Should I take Prozac if I’m pregnant?
- What drugs or food should I avoid when taking Prozac?
- How will I know this medication is working?
- What if I no longer want to take Prozac?
- What side effects should I look out for?
Final Thoughts
Determining if Prozac is a good fit for you takes time. Keeping track of side effects as they happen and working with your care team to reduce them can help you achieve successful results. Maintaining a log of your prescription activity (schedule of dosage, negative reactions, etc.) allows you to address any issues along the way.
For Further Reading
- Antidepressants: Selecting one that’s right for you – Mayo Clinic
- Fluoxetine (Prozac) – National Alliance on Mental Illness
