Prozac Drug Interactions

Major depression is one of the most common forms of mental illness in the United States, with tens of millions of U.S. adults affected on an annual basis.

If you’ve been diagnosed with depression, your mental health provider may prescribe Prozac® to treat your symptoms and help you recover.

Prozac is a safe and effective medication for most people with depression. However, there are several Prozac drug interactions that you should be aware of if you use this medication to treat depression or other forms of mental illness. 

Below, we’ve explained what Prozac is, how it works and the most common drug interactions to be aware of if you’re prescribed Prozac.

We’ve also shared some simple tips to help you minimize your risk of drug interactions and use Prozac as safely as possible. 

Prozac is a prescription medication that’s used to treat major depression, obsessive-compulsive disorder, panic disorder and bulimia nervosa. It contains the active ingredient fluoxetine and is available as a capsule, tablet and liquid solution.

Fluoxetine, the ingredient in Prozac, belongs to a class of medications called selective serotonin reuptake inhibitors, or SSRIs. It works by increasing the levels of serotonin, a neurotransmitter, in your brain and body.

Serotonin plays an important role in regulating your thoughts, feelings and behavior. Low levels of serotonin are associated with depression, anxiety, suicidal behavior and an increased risk of other emotional disorders, while high levels are linked to decreased arousal.

Experts believe that the increase in serotonin levels caused by fluoxetine and other SSRIs can reduce the severity of depression symptoms and help to facilitate recovery.

Since the mid-20th century, several classes of antidepressant medications — including older drugs, such as tricyclic antidepressants (TCAs) and monoamine oxidase inhibitors (MAOIs) — have been used to treat major depressive disorder and other types of depression. 

Many of these older antidepressant drugs are well known for causing side effects and interacting with other medications. For example, MAOI drugs — which were commonly used throughout the 20th century — are infamous for interacting with other medications and with some foods and drinks.

Today, SSRIs such as fluoxetine have replaced these antidepressant drugs as first-line treatments for depression due to their improved safety and lower risk of an adverse reaction.

While Prozac, generic fluoxetine and similar SSRIs are less likely to cause interactions than old antidepressant medications, they can still interact with other medications and supplements. In some cases, these interactions may be harmful to your health and wellbeing.

Medications That Increase Serotonin Levels

Prozac and other SSRIs should not be used with any other medications or supplements that increase your serotonin levels.

When Prozac or generic fluoxetine are used with other serotonergic drugs, they may cause a dangerous increase in serotonin levels called serotonin syndrome. This is a serious, potentially fatal drug interaction that often requires urgent medical care.

Symptoms of serotonin syndrome include elevated blood pressure, hyperthermia, tachycardia (fast heart rate), dilation of the pupils, shivering, tremor, diaphoresis (abnormal sweating) and jerky, overly responsive reflexes.

When severe, serotonin syndrome can cause dramatic changes in blood pressure and pulse rates, as well as seizures, respiratory distress and potentially even death.

Medications and supplements that raise serotonin levels and can cause symptoms of serotonin syndrome when used with Prozac include:

• Other SSRIs and serotonin-norepinephrine reuptake inhibitors (SNRIs)

• Tricyclic antidepressants and monoamine oxidase inhibitors

• Bipolar disorder medications, such as lithium

• Triptans

• Tramadol for premature ejaculation

• Buspirone

• Amphetamines

• St. John’s wort

To avoid the risk of serotonin syndrome, make sure to tell your healthcare provider about any prescription drugs, over-the-counter medications and/or supplements you take or have recently taken before using Prozac or generic fluoxetine. 

Other Prozac Drug Interactions

In addition to serotonin syndrome, other symptoms and safety issues may occur when Prozac is used with other medications. Make sure you’re aware of the following additional interactions and safety risks before using Prozac or generic fluoxetine: 

• Using Prozac or generic fluoxetine with warfarin, aspirin and other medications that can affect the blood clotting process may cause abnormal bleeding, including a higher risk of gastrointestinal bleeding.
  

• Prozac and generic fluoxetine can interact with ibuprofen and other NSAIDs, causing a risk of abnormal bleeding.
  

• When used with pimozide or thioridazine, Prozac and generic fluoxetine may cause QT interval prolongation (slow heart muscle contraction and relaxation).
  

• When used with benzodiazepines (a class of medications used to treat anxiety), Prozac and generic fluoxetine may increase the severity of certain side effects, such as reduced psychomotor performance (coordination and motor skills).
  

• Prozac and generic fluoxetine may increase the effects of medications that affect central nervous system function.
  

• Prozac and generic fluoxetine can inhibit the cytochrome P450 2D6 (CYP2D6) enzyme pathway. This may affect the metabolism and efficacy of some other medications and supplements. 

Like other SSRIs, Prozac can cause side effects. Many side effects of Prozac are temporary and mild, although some adverse effects may be persistent and/or severe. Common side effects of Prozac and generic fluoxetine include:

• Abnormal dreams

• Anorexia

• Anxiety

• Diarrhea

• Dry Mouth

• Dyspepsia (indigestion)

• Erectile dysfunction (ED)

• Flu syndrome

• Insomnia

• Nausea

• Nervousness

• Pharyngitis (sore throat)

• Reduced sex drive

• Sexual dysfunction and reduced sexual ability

• Sinusitis

• Skin rash

• Somnolence (drowsiness)

• Sweating

• Tremor

• Vasodilation

• Yawning

Although uncommon, Prozac and generic fluoxetine can cause more severe and persistent side effects.

When it’s used correctly, Prozac is generally a safe and effective medication. Use the tips below to take Prozac or generic fluoxetine safely and reduce your risk of experiencing any side effects or adverse interactions:

• Follow the instructions from your healthcare provider. Make sure to use Prozac as directed by your healthcare provider. Take the initial dose prescribed to you and inform your healthcare provider if you experience any side effects.
  

• Inform your healthcare provider about any medications you use. To reduce your interaction risk, make sure to let your healthcare provider know about all medications, including other antidepressants, that you currently use or have recently used.
  

• Take Prozac at the same time every day. Prozac is usually taken once per day in the morning or twice per day in the morning and at midday. Try to take Prozac around the same time each day and maintain a consistent schedule.
  

• Wait for several weeks before assessing your results. Prozac is effective, but it can take time to start working. You may need to take Prozac or generic fluoxetine for four to five weeks before you notice any improvements in your depression symptoms.
  If you don’t notice any changes after using Prozac for five weeks, it’s best to talk to your healthcare provider.
  

• Don’t ever take a double dose of Prozac. If you forget a dose of Prozac, it’s okay to take it as soon as you remember. However, if it’s close to the time for your next dose, skip the missed dose and continue to use Prozac as normal.
  

• Talk to your healthcare provider before using herbal supplements. Some dietary supplements, including St. John’s wort and tryptophan, may interact with Prozac and cause potentially harmful symptoms.
  If you’re prescribed Prozac or generic fluoxetine, make sure to talk to your healthcare provider before using any dietary supplements or herbal depression treatments.
  

• If you experience side effects, let your healthcare provider know. Side effects are possible with any antidepressant, and Prozac is no exception. If you develop any side effects while using Prozac, don’t feel hesitant to let your healthcare provider know.
  Your healthcare provider may adjust your dosage of Prozac or switch you to a different antidepressant that’s more suited to your needs.
  

• Don’t adjust your dosage or stop taking Prozac without direction from your healthcare provider. Like other SSRI antidepressants, Prozac and generic fluoxetine can cause withdrawal symptoms if you suddenly lower your dosage or stop taking your medication.
  If you want to stop taking Prozac, talk to your healthcare provider. They’ll help you safely reduce your dosage and avoid any adverse events from withdrawal. 

Prozac is one of several medications used to treat depression. Like other antidepressants, it’s important to take Prozac safely by sticking to your prescribed dosage and understanding your risk of drug interactions.

If you’re worried about an interaction or adverse reaction from Prozac, it’s best to reach out to your healthcare provider for more information.

We offer fluoxetine (a generic version of Prozac) online, following a consultation with an online licensed psychiatry provider. We also offer a full range of mental health services, including the ability to connect with a licensed provider for an online psychiatric evaluation.

Interested in learning more about depression? Our guide to the symptoms of depression goes into detail about what depression feels like, while our list of depression treatments covers your options if you’re feeling depressed and want to seek help.