Key takeaways:
If you miss a dose of Prozac (fluoxetine), take it as soon as you remember unless it’s almost time for your next dose. Never take 2 doses at once.
Prozac stays in your body longer than many other antidepressants. This means that missing 1 dose of Prozac is less likely to cause withdrawal symptoms.
Prozac works best when taken every day or once-weekly as prescribed. If you’re thinking about stopping Prozac, talk to your healthcare team first.
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Prozac (fluoxetine) is a selective serotonin reuptake inhibitor (SSRI) that’s commonly prescribed to treat depression and other mental health conditions. It works by raising serotonin levels in the brain, which helps regulate your mood.
It’s important to take Prozac every day or once weekly as prescribed. But it’s normal to forget a dose from time to time.
Here’s what to know about a missed dose of Prozac, including what to do next, possible side effects, and how to help prevent missed doses in the future.
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What should you do if you miss a dose of Prozac?
If you miss a dose of Prozac, don’t panic. In most cases, you should take the missed dose as soon as you remember. But if it’s almost time for your next scheduled dose, skip the missed dose and take your next dose at the usual time.
Use the chart below to find out what to do based on your missed-dose situation.
Missed-dose situation | What you should do |
|---|---|
You remember within a few hours of your scheduled dose | Take the missed dose as soon as you remember. Then take your next dose at your usual time. |
It’s close to or time for your next scheduled dose | Skip the missed dose and take your next dose at your usual time. Don’t take 2 doses to make up for the missed one. |
You’ve missed more than 1 day of Prozac | Take your next scheduled dose at the usual time. If you’ve missed several doses, contact your healthcare team. |
You’ve missed more than a week of Prozac | Contact your prescriber before restarting Prozac. They can recommend the safest way to continue treatment. |
You’ve missed your once-weekly dose of Prozac | Take your dose as soon as you remember, then continue taking it on your usual weekly schedule. If it’s time for your next scheduled weekly dose, skip the missed dose and take your next weekly dose. |
You’re having side effects after a missed dose | Mild symptoms, such as headache or nausea, may improve as you get back on your regular schedule. If your side effects are severe or don’t go away, contact your prescriber or seek medical care right away. |
Keep in mind that you shouldn’t take 2 doses at the same time or take extra Prozac to make up for a missed dose. Taking more than prescribed can raise your risk of side effects, including serotonin syndrome, a rare but potentially life-threatening issue.
If you’re not sure what to do after missing a dose of Prozac, ask your pharmacist or prescriber. They can tell you the safest way to get back on your regular schedule.
What happens if you miss a dose of Prozac?
Many people won’t notice any symptoms after missing 1 dose of Prozac. That’s because Prozac lasts longer in the body than most other SSRIs. After you take a dose of Prozac, it breaks down in your liver to an active chemical called norfluoxetine. Both fluoxetine and norfluoxetine work to improve your mood. Fluoxetine can last in your body for about 1 month, while norfluoxetine can last for about 2.5 months.
But if you miss several doses in a row, Prozac levels can begin to fall. In this case, there’s a higher chance that depression or other symptoms related to your mental health condition will come back.
For Prozac to work its best, it’s important to take it as directed on a daily or weekly basis. If you’re having trouble remembering your medication, ask your healthcare team for guidance.
Can missing a dose of Prozac cause withdrawal symptoms?
Antidepressant discontinuation syndrome (withdrawal symptoms) is possible if you’ve been taking Prozac for 4 weeks or longer and then stop it abruptly. Although this is less likely with Prozac than with other SSRIs. Here are common withdrawal symptoms to look for:
Dizziness
Flu-like symptoms (chills, runny nose)
Tingling or zapping sensations
Balance problems
Anxiety
Light sensitivity
Noise sensitivity
Restlessness
Most withdrawal symptoms go away within 1 to 3 days of restarting your medication. But if you develop severe side effects or symptoms that don’t go away, contact your prescriber as soon as possible.
Good to know: Once-weekly Prozac is designed to stay in your body for a full week. Missing 1 weekly dose of Prozac is also unlikely to cause withdrawal symptoms. Still, it’s important to take your dose on schedule to help Prozac work its best.
How to prevent missing Prozac doses
It’s a good idea to take Prozac at the same time each day. If you take once-weekly Prozac, take it on the same day each week and, if possible, at the same time.
Building a routine, such as taking Prozac with your first meal of the day, can make it easier to remember to take your medication.
Other helpful reminders for taking your medication include:
Setting an alarm on your phone
Using a weekly pill organizer
Keeping your medication where you’ll see it, such as near the coffeepot (but safely away from children and pets)
Using a medication reminder app
If you frequently forget to take Prozac, let your healthcare team know. They may have suggestions to help you stay on track, such as switching from daily to once-weekly Prozac (or vice versa).
Can you stop taking Prozac suddenly?
You shouldn’t stop taking Prozac on your own. If you’re feeling better, that’s a sign that Prozac is helping you manage your symptoms. Keep in mind that it can take up to 8 weeks to feel the full effects of Prozac and other antidepressants. So it’s important to give the medication plenty of time to work before you decide to stop taking it.
If you stop taking Prozac too soon, there’s also a chance your symptoms could return. This is known as a relapse. Most experts recommend taking Prozac and other SSRIs for at least 6 months after your symptoms improve. This helps reduce the chance of relapse.
If you suddenly stop taking Prozac — or if you lower your dose too quickly — you might experience withdrawal symptoms. These include tiredness, dizziness, and more.
That being said, if you want to stop taking Prozac, talk with your prescriber first. They can help address side effects or other concerns you may have. They can also help you stop taking the medication in a safe way.
How to save on Prozac
There are many ways to save on Prozac, which is available as both a brand-name and generic medication. Choosing the generic version can help lower your prescription costs.
Save with GoodRx: The price of 30 capsules of generic fluoxetine 20 mg is as low as about $9 at certain pharmacies with a free GoodRx discount.
Save with Companion: You can access discounted prescription medications with a GoodRx Companion subscription. Over 200 medications (including some forms of generic Prozac) are available for free, with hundreds more under $10. The program also includes benefits to help you cut your self-pay costs, such as lower prices for online care visits, discounts on dental care, and other health services.
Save with a 90-day supply: Depending on your pharmacy and insurance plan, you may be able to save money by filling a 90-day supply. Plus, you won’t have to refill your medication as often. If you’re paying cash, compare the price for a 30-day supply versus a 90-day supply. It may cost more up front, but overall you could pay less than you would for three 30-day fills.
Frequently asked questions
For most people, it’s best to take Prozac in the morning. This is because it can cause insomnia (trouble sleeping). Taking it early in the day may help lower your chance of sleep problems. If Prozac makes you feel sleepy instead, ask your healthcare professional if taking it later in the day is a better option.
When you find a time that works for you, stick with it. Taking Prozac at the same time every day — or the same day every week for once-weekly dosing — can help it work more effectively.
Prozac doesn’t start working right away. Instead, many people notice gradual improvements over several weeks.
The biggest sign that Prozac is working is that your symptoms start to improve. For example, you may feel less down, have more energy, or find it easier to do your daily activities. Keep in mind that everyone responds differently to antidepressants. And it may take 4 to 8 weeks to experience Prozac’s full benefits. But if your symptoms don’t improve or get worse, tell your prescriber.
For most people, it’s best to take Prozac in the morning. This is because it can cause insomnia (trouble sleeping). Taking it early in the day may help lower your chance of sleep problems. If Prozac makes you feel sleepy instead, ask your healthcare professional if taking it later in the day is a better option.
When you find a time that works for you, stick with it. Taking Prozac at the same time every day — or the same day every week for once-weekly dosing — can help it work more effectively.
Prozac doesn’t start working right away. Instead, many people notice gradual improvements over several weeks.
The biggest sign that Prozac is working is that your symptoms start to improve. For example, you may feel less down, have more energy, or find it easier to do your daily activities. Keep in mind that everyone responds differently to antidepressants. And it may take 4 to 8 weeks to experience Prozac’s full benefits. But if your symptoms don’t improve or get worse, tell your prescriber.
The bottom line
If you miss a dose of Prozac (fluoxetine), take it as soon as you remember unless it’s almost time for your next scheduled dose. Never take 2 doses of Prozac at once to make up for a missed dose.
Prozac stays in your body longer than many other antidepressants. So missing 1 dose isn’t likely to cause withdrawal symptoms. But taking Prozac every day or once weekly as prescribed helps it work best, so use reminders if needed. Talk to your prescriber before stopping treatment or if you have questions about a missed dose of Prozac.
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References
Dr. Reddy’s Laboratories Limited. (2025). Fluoxetine hydrochloride- fluoxetine hydrochloride capsule, delayed release pellets [package insert].
Edinoff, A. N., et al. (2021). Selective serotonin reuptake inhibitors and adverse effects: A narrative review. Neurology International.
MedlinePlus. (2025). Fluoxetine.
Parry, T. (Ed.). (2025). Antidepressant withdrawal syndrome - update. Therapeutics Letter.
