How To Start Prozac Again After Stopping

In our latest question and answer, the pharmacist discusses several methods of how to appropriately start Prozac (fluoxetine) again after having stopped the medication.

Question

I have been off Prozac (fluoxetine) for about 6 months now and have noticed that depression and worry coming back. I have some of the 40mg left and are still good. Would it be safe to say, I can start taking the 40mg every day or should I take one every other day to start?

Asked by Lynn On Sep 23, 2022

Answered by
Medical Content Reviewed By HelloPharmacist Staff

Published Sep 23, 2022
Last updated Sep 23, 2022

Key points

  • There are multiple ways to re-initiate Prozac therapy after stopping, based on how long you have been off the drug.
  • If you stopped Prozac and have only been off of the drug for about a month or so, you can sometimes be restarted at your previous dose.
  • If you have been off Prozac for a considerable amount of time (generally 2 months or more), it is recommended to start again at a low dose, and slowly titrate your way back up.
  • Be sure to speak to your doctor about your options.

Thanks for reaching out to us! How to start taking Prozac (fluoxetine) again after stopping depends on your particular situation.

Starting Again After Being Off Prozac For A Long Time

If you have been off of Prozac (fluoxetine) for a long enough period of time for it to be completely eliminated from your system, studies indicate that you can be re-initiated at a low dose and titrated up to effect. This means that you most likely will be starting on a lower dose than what you were previously taking.

While this method may not provide more immediate relief of depressive symptoms, it is a prudent approach to avoid side effects and find the lowest, most effective dose for you (which may have changed). 

Most side effects tend to occur when the medication is first 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 it for 4-12 weeks.

A low starting dose of Prozac is generally 10mg to 20mg daily, and increasing by 10mg or so every few weeks until you reach the desired dose.

Starting Again After Being Off A Short Time

Some studies show that if you relapse soon after discontinuation of Prozac (within a month or two), therapy can be re-initiated at your prior dose. This method provided adequate, and quick relief of depressive symptoms, although it was associated with a slight increase in side effects (although generally not as many side effects as starting Prozac for the first time).

While a month or two may seem like a long time to be off a medication, with Prozac, that's not quite the case, as the drug stays in your system for a considerable amount of time. Much longer than most other antidepressants.

Prozac Lasts A Long Time In Your System

Prozac has a long half-life (i.e. time for 50% of the drug to be metabolized).

Sources indicate that it ranges from 8-14 days. This means that it can take over 2 months for the drug to be completely eliminated from the body!

However, six months, the time that you have been off the drug as you state in your question, is a long enough time for Prozac (fluoxetine) to be no longer present in the body and that is why low dose initiation is recommended for you (versus starting at your previous dose).

Speak With Your Doctor As Options Vary

Be sure to speak with your doctor regarding your best option here. While the general recommendation is to start at a low dose and titrate up, if you are having severe and debilitating symptoms, your doctor may recommend starting at your last dose that was effective. You may experience more side effects, however.

Starting a high dose may cause the following:

  • Nausea
  • Headache
  • Diarrhea
  • Drowsiness
  • Dry mouth 
  • Libido decrease

If you and your doctor do decide to start at a low dose and taper up, the following is one recommended way:

  • Start with 10-20 mg/day. The dosage can be increased after 2-3 weeks by 10 to 20 mg to effect.

Final Words

To reiterate, studies indicate that there are multiple ways to re-initiate Prozac therapy after stopping, based on how long you have been off the drug.

Generally speaking, you can be re-initiated on your last successful dosage level if it has been a relatively short amount of time since discontinuation (<2 to 3 months). Additionally, if symptoms are severe, it may be more beneficial to re-initiate at your last successful dose. However, this is associated with a slightly higher risk of side effects.

If it has been long enough for the drug to be completely eliminated from your system, it may be prudent to start at a low dosage (e.g. 20 mg per day) and titrate up to an effective dose. Speak with your doctor regarding the best option for your specific situation.

References

  • Prozac Prescribing Information, AccessFDA
  • Fluoxetine Monograph, PubChem
  • SSRI Antidepressant Medications: Adverse Effects and Tolerability, PubMed
  • Treatment approaches to major depressive disorder relapse. Part 2: reinitiation of antidepressant treatment, PubMed
  • PRACTICE GUIDELINE FOR THE Treatment of Patients With Major Depressive Disorder, Psychiatry Online

About the Pharmacist

Dr. Brian Staiger, PharmD

Dr. Brian has been practicing pharmacy for over 11 years and has wide-ranging experiences in many different areas of the profession. From retail, clinical and administrative responsibilities, he's your knowledgeable and go-to source for all your pharmacy and medication-related questions! Feel free to send him an email at Hello@HelloPharmacist.com! You can also connect with Dr. Brian Staiger on LinkedIn.

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