Can You Start Prozac Again After Stopping On Your Own?

In our latest question and answer, the pharmacist discusses whether or not it is a good idea to start taking Prozac again to combat anxiety symptoms after stopping it (without being under the supervision of a qualified health care practitioner).

Can You Start Prozac Again After Stopping On Your Own?
Jul 08, 2020

Frank asked

I have been off of fluoxetine 20 mg since July of 2018 which was prescribed because of anxiety and was taking it along with clonazepam 0.5 mg. I took myself off of fluoxetine because I had been doing well. I just stayed with clonazepam only as needed. With all that is going on with this pandemic, I have been experiencing anxiety on a daily basis with some depression. I still have some leftover fluoxetine which states discard after 12/28/2019. First of all, can I restart taking it without seeing a doctor and can I continue with what I have?

At a glance

  • SSRI’s like Prozac are not fast acting medications. They can take anywhere from 4-12 weeks for you to see benefits. This is typically the case if you are just starting or restarting the medication. About 15% of patients experience anxiety when starting a SSRI that usually resolves.
  • I would recommend speaking with your physician before resuming your medication.
  • Assuming that you stored the fluoxetine at room temperature and a dry place, it is probably still good, but I would recommend disposing it.


Hi Frank and thank you for your question. I certainly understand your increased levels of anxiety over the last few months. I think that many of us are experiencing similar feelings. 

Fluoxetine (or under the brand Prozac) was the first selective serotonin reuptake inhibitor approved for use over 30 years ago, so we have decades of research. When it comes to fluoxetine, most side effects tend to occur when the medication is started or restarted. Generally, these side effects gradually resolve and you’ll start to experience the positive antidepressant effects of the medication after being on the medication for 4-12 weeks. 

Now, there are a few reasons why I think it would be inappropriate to resume the medication without letting your physician know. First, the medication takes a while to show positive effects and you’ve been off of it for a while. While uncommon, some people do experience serious side effects while starting or restarting an antidepressant and it, therefore, is important that you be under the supervision of your doctor to monitor you.

Secondly, your entire medical situation needs to be taken into consideration before starting (or restarting in this case) any medication. You could have a new condition or be taking other meds that could preclude using fluoxetine safely.

I imagine, at the very least, that your physician would want to know that you restarted the medication so that they can monitor your progress and follow up with you after a few weeks of therapy. 

Lastly, regarding your medication stability and potency; it might still be ok, but I can’t say for sure since stability studies aren't generally done past the listed expiration date. I also don't know if the expiration date you refer to is the date on your prescription vial or the date the was listed on the manufacturer's stock bottle.

Fluoxetine 20mg is a very common medication and a “fast mover” at most pharmacies that I've worked at. Usually, a bottle doesn't last longer than a month or two on the shelf before we’ve dispensed it all and have to open up another one. Typically, most bottles don’t expire for two or more years when they get to the pharmacy. We automatically put an expiration date of the actual expiration date or a year from the dispensed date, whichever is shorter, so it is likely your expiration date is referencing a year after it was dispensed.

This expiration date of one-year that is put on dispensed prescription bottles is to ensure that you not only taking a fully-potent (i.e. non-degraded) medication but also to ensure that you are having regular follow-ups with your doctor (i.e. you ideally shouldn't go more than a year without some sort of follow-up).

In terms of medication stability after one year, assuming that you stored your medication in a cool, low light, not too humid environment, your medication is probably good for quite a while longer. Solid, non-protein based drugs like fluoxetine are generally pretty stable. That being said, fluoxetine is generally pretty inexpensive and since we don't know for sure it is 'still good', I would recommend disposing of it and getting a new prescription filled for it after speaking with your physician, just to be safe.

  • Fluoxetine monograph, PubChem
  • What are the clinical implications of new onset or worsening anxiety during the first two weeks of SSRI treatment for depression?, Depression and Anxiety
  • CFR Code of Federal Regulations Title 21, FDA

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