Key takeaways:
Prozac (fluoxetine) and Zoloft (sertraline) belong to a group of medications called selective serotonin reuptake inhibitors (SSRIs). They treat many health conditions, including anxiety disorders.
Prozac and Zoloft are thought to be similarly effective for generalized anxiety disorder and panic disorder. But Zoloft may be more effective for social anxiety disorder.
Prozac and Zoloft have similar side effects. But Prozac is known to have more interactions.
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We all get a little anxious from time to time. From sweaty palms on a first date to knocking knees before a big presentation — these are normal responses to stress.
But if feelings of anxiety regularly interfere with your daily life, it’s important to check in with your healthcare team. If they believe you have an anxiety disorder, you’ll have many treatment options. This includes cognitive behavioral therapy (a type of psychotherapy), lifestyle changes, and/or medication.
Prozac (fluoxetine) and Zoloft (sertraline) are two medications commonly prescribed for anxiety. They’re part of the same group of medications and share some similarities. But they have many differences, too.
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1. Prozac and Zoloft have different uses
Prozac and Zoloft belong to a group of medications called selective serotonin reuptake inhibitors (SSRIs). Both medications are FDA approved to treat a type of anxiety disorder called panic disorder.
In addition to panic disorder, Prozac is approved to treat:
Zoloft is also approved to treat:
OCD
MDD
Social anxiety disorder (SAD)
Both medications have off-label uses, too. Prozac is often prescribed off label for generalized anxiety disorder (GAD), SAD, and others. Zoloft is sometimes prescribed off label for GAD.
Medications for generalized anxiety disorder (GAD): Learn about the many types of medications that treat GAD, from antidepressants and antipsychotics to benzodiazepines.
Prozac side effects: Check out the key side effects to be aware of when taking Prozac (fluoxetine).
Zoloft side effects: Zoloft (sertraline) has side effects too. Find out ways to manage them.
Good to know: A medication called Symbyax combines fluoxetine, Prozac’s active ingredient, with olanzapine in one pill. This combination pill is approved to treat treatment-resistant depression and depression symptoms in people with bipolar disorder.
2. Prozac and Zoloft work similarly for anxiety
SSRIs, such as Prozac and Zoloft, increase serotonin levels in the brain. Serotonin is a natural chemical in your body. It acts as a messenger that transports chemical messages between your nerves. This is thought to help regulate many bodily functions, including your sleep, digestion, and mood.
Many experts believe that low serotonin levels are associated with anxiety. But we aren’t completely sure just how significant serotonin’s role in anxiety is. Other factors, like your brain structure and even your gut microbiome, may also play a role.
For now, most experts agree that SSRIs improve anxiety-related symptoms in many people who take them.
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3. Prozac and Zoloft have similar side effects overall
Prozac and Zoloft share common side effects. But there are some differences, too.
In clinical studies, people taking Prozac to treat panic disorder were most likely to experience:
Nausea
Diarrhea
Trouble sleeping
Nervousness
Similar studies of people taking Zoloft for panic disorder found that its most common side effects were:
Nausea
Diarrhea
Trouble sleeping
Dry mouth
Tiredness
Dizziness
Common side effects of both Prozac and Zoloft include headache, changes in appetite, and sexual dysfunction (like ejaculation problems and low sex drive). While most of these side effects improve over time, sexual side effects may last for the duration of treatment.
Good to know: For more detailed information on Prozac side effects and Zoloft side effects, check out our other articles on these topics.
Serious side effects of Prozac and Zoloft
All SSRIs, including Prozac and Zoloft, have a boxed warning for the risk of suicidal thoughts and behaviors. Boxed warnings are the strongest warning the FDA can give a medication. The risk may be highest in people who are less than 25 years of age and during the first few months of treatment.
Other rare but serious side effects of Prozac and Zoloft include:
Abnormal heart rhythms
Manic episodes (intense feelings of energy) in people with bipolar disorder
Higher risk of bleeding
High serotonin levels (serotonin syndrome)
Antidepressant discontinuation syndrome if you abruptly stop Zoloft or Prozac
4. Prozac and Zoloft have unique dosages and formulations
Prozac and Zoloft both come in multiple formulations that are taken by mouth. But there are some differences you should know about.
Prozac
Prozac comes in the following formulations, some of which are only available as generics:
Tablets: 10 mg, 20 mg, 60 mg
Capsules: 10 mg, 20 mg, 40 mg
Delayed-release (DR) capsules: 90 mg
Liquid solution: 20 mg/5 mL
The DR capsules are only taken once a week. Other forms of Prozac are usually taken once daily in the morning, with or without food. If you’re taking a higher dosage, you may have to take two doses per day. Taking it with food may help prevent stomach upset, a common side effect of Prozac.
The starting Prozac dosage for panic disorder is usually 10 mg per day. For other conditions, it ranges between 20 mg to 60 mg per day. Your healthcare professional may increase the dose every several days to weeks. The maximum dosage is usually 60 mg per day but can go up to 80 mg per day for OCD.
Zoloft
Zoloft is usually taken once daily, with or without food. Like Prozac, taking it with food may help prevent an upset stomach. It comes in the following formulations, some of which are only available as a generic:
Capsules: 150 mg, 200 mg
Tablets: 25 mg, 50 mg, and 100 mg
Liquid solution: 20 mg/mL
The starting Zoloft dosage is usually 25 mg daily for panic disorder. It’s between 25 mg to 50 mg for other health conditions. Your healthcare professional may increase your dose by 25 mg to 50 mg on a weekly basis. The maximum dosage is 200 mg per day for most health conditions.
If you’re taking the concentrated liquid solution, you should mix it with 4 oz of liquid right before you take it. If you don’t mix Zoloft solution with liquid, it can numb your mouth and tongue for over a day. Water, ginger ale, and lemonade are all options for diluting the medication.
Comparing Prozac and Zoloft dosages for panic disorder
Prozac | Zoloft | |
Generic name | Fluoxetine | Sertraline |
Available formulations | • Tablets: 10 mg, 20 mg, 60 mg • Capsules: 10 mg, 20 mg, 40 mg • Delayed-release (DR) capsules: 90 mg • Liquid solution: 20 mg/5 mL | • Capsules: 150 mg, 200 mg • Tablets: 25 mg, 50 mg, 100 mg • Liquid solution: 20 mg/mL |
Typical starting dosage | 10 mg per day | 25 mg per day |
Maximum daily dosage | 60 mg per day | 200 mg per day |
5. Prozac and Zoloft performed slightly differently in clinical trials
Prozac and Zoloft are both effective at treating anxiety. You may notice an improvement in your anxiety in as little as 2 weeks. But since your healthcare professional may increase your dose over several weeks, it can take 1 to 2 months before you feel full effects.
What the studies show
Prozac has been shown to improve anxiety symptoms in panic disorder clinical trials. Other studies have found that it can also improve GAD symptoms, but the medication's effectiveness for treating SAD is less clear.
For example, Prozac was tested in two clinical studies to treat panic disorder. In both studies, it was compared to a placebo, which is a pill with no active ingredients. Everyone who took Prozac started with a dose of 10 mg per day, and their dose was increased to between 20 mg and 60 mg per day. After 12 weeks (3 months), about half of the people taking Prozac no longer had panic attacks. By comparison, about one-third of people taking the placebo stopped having panic attacks after 12 weeks.
Zoloft has also shown to improve symptoms of panic disorder. In two clinical studies for panic disorder, Zoloft was compared to a placebo. Everyone who took Zoloft started with a dose of 25 mg per day, and their dose was increased by 50 mg each week — up to a maximum of 200 mg per day. People who took Zoloft had fewer panic attacks, averaging about 2 fewer per week compared to those who took placebo. Additional study data speaks to Zoloft’s ability to treat SAD and GAD.
6. One isn’t widely considered better than the other
The studies discussed above speak to Prozac and Zoloft’s individual effectiveness for treating certain types of anxiety. But a few other studies and analyses are available that more directly compare Prozac to Zoloft. This helps us determine which one might be more effective in specific situations.
Panic disorder: A review of over 87 studies compared multiple SSRIs for the treatment of panic disorder. Zoloft was one of the most effective SSRIs with the lowest risk of side effects. Prozac was also effective but had a higher risk of side effects.
GAD: A review of 27 randomized controlled trials (the best type of study to check for cause and effect) found that Prozac may be the most effective SSRI at treating GAD. But the study found that Zoloft may have the least amount of side effects.
SAD: Prozac is considered less effective than other SSRIs at treating SAD. Some studies have found that Prozac isn’t more effective than placebo at treating SAD. But multiple studies have shown that Zoloft is more effective than placebo.
Depression: A study comparing Prozac, Zoloft, and Paxil (paroxetine) in people with depression and high levels of anxiety found that these SSRIs worked similarly well and were well-tolerated.
So, what’s the verdict? For GAD and panic disorder, Prozac and Zoloft are both effective options. Zoloft is likely a better option for treating SAD. But both are similarly effective for managing depression.
7. Prozac causes slightly more interactions
Prozac and Zoloft both have interactions. Prozac’s interactions tend to be similar to Zoloft’s interactions overall.
Prozac and Zoloft can increase the levels of other medications. This may lead to increased side effects of Prozac, Zoloft, or the other medication. Examples include:
Some antiarrhythmics, such as propafenone and flecainide
Beta blockers, such as metoprolol (Lopressor, Toprol XL) and nebivolol (Bystolic)
Some tricyclic antidepressants (TCAs), such as imipramine and desipramine (Norpramin)
Dextromethorphan (Delsym)
Venlafaxine (Effexor XR)
Other medications that have similar effects as Prozac and Zoloft can also interact. When combined, the general risk of side effects goes up. This includes:
Medications that increase serotonin levels, such as many other antidepressants, triptans, and tramadol (ConZip)
Medications that can cause abnormal heart rhythms, such as quinidine and methadone (Methadose)
Medications that can cause bleeding, such as nonsteroidal anti-inflammatory drugs (NSAIDs) and anticoagulants
Prozac may also interact with narrow therapeutic index drugs. These are medications that can become easily toxic at slightly high doses. These include lithium (Lithobid), digoxin (Lanoxin), and phenytoin (Dilantin, Phenytek).
You shouldn't take certain medications with Prozac or Zoloft at all. These include pimozide and monoamine oxidase inhibitors (MAOIs). If you’re taking an MAOI, you should stop it at least 2 weeks before starting Prozac or Zoloft. And thioridazine also shouldn’t be used within 5 weeks of taking Prozac. But don’t make any changes without talking to your healthcare professional first.
Keep in mind: This isn’t a complete list of possible interactions with Prozac and Zoloft. It’s a good idea to have your pharmacist or prescriber check for any potential interactions. Giving them an updated list of your medications will help them check.
8. There are ways to save on Prozac and Zoloft
Prozac and Zoloft are both available as brand-name medications. But you can also find them as lower-cost generics. GoodRx can help you navigate ways to save on your prescription.
Save with GoodRx: A 30-day supply of generic Prozac at certain pharmacies costs as low as $3.00 with a free GoodRx coupon. A similar quantity of generic Zoloft may cost as low as $9.25.
Save with a copay savings card: If you have commercial insurance and meet eligibility requirements, brand-name Zoloft’s price is as little as $4 if you use the manufacturer’s savings card.
Frequently asked questions
It’s possible. Talk with your healthcare professional if you want to switch from Prozac to Zoloft (or vice versa). There are different ways to make the switch. For instance, your prescriber might suggest slowly lowering the dose of your current medication you’re stopping and starting the new one right away. Alternatively, they may have you take both medications for a short time or go through a "washout period," where you don’t take either medication for a while.
The term “Prozac eyes” refers to specific eye movements that happen during certain stages of sleep, known as NREM and REM. These eye movements can happen with all SSRIs but are known to happen most often with Prozac. These eye movements can continue after you stop taking Prozac, but they don’t usually cause any issues. Prozac may also cause other eye-related side effects, including eye pain, changes in vision, and redness.
No, you can’t take Prozac and Zoloft together. They work the same way to relieve anxiety. Taking them together may increase the risk of side effects without any added benefit.
It’s possible. Talk with your healthcare professional if you want to switch from Prozac to Zoloft (or vice versa). There are different ways to make the switch. For instance, your prescriber might suggest slowly lowering the dose of your current medication you’re stopping and starting the new one right away. Alternatively, they may have you take both medications for a short time or go through a "washout period," where you don’t take either medication for a while.
The term “Prozac eyes” refers to specific eye movements that happen during certain stages of sleep, known as NREM and REM. These eye movements can happen with all SSRIs but are known to happen most often with Prozac. These eye movements can continue after you stop taking Prozac, but they don’t usually cause any issues. Prozac may also cause other eye-related side effects, including eye pain, changes in vision, and redness.
No, you can’t take Prozac and Zoloft together. They work the same way to relieve anxiety. Taking them together may increase the risk of side effects without any added benefit.
The bottom line
Prozac (fluoxetine) and Zoloft (sertraline) are selective serotonin reuptake inhibitor (SSRI) medications that can treat anxiety disorders. Both medications are FDA approved for panic disorder and are effective options for this use. Neither medication is approved for generalized anxiety disorder (GAD), but both are considered first-choice treatments for this condition. Zoloft is likely more effective than Prozac for social anxiety disorder (SAD).
Both medications have similar side effects, though Prozac is known to have more interactions. If you have any questions about Prozac versus Zoloft, and which SSRI might be right for you, talk to your healthcare professional. They can help you make a decision based on individual factors, including your medical history and personal preferences.
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