Can Prozac (fluoxetine) make you tired or sleepy?
Yes. Prozac can cause tiredness or sleepiness in some people. Drug labeling and clinical experience commonly list fatigue and/or drowsiness as possible side effects of fluoxetine, so it can feel like you are more tired than usual after starting the medication or after dose changes.
What does Prozac fatigue feel like?
People who report this side effect often describe it as:
- being more tired during the day than before
- low energy or reduced motivation
- feeling drowsy, especially at certain times of day
If you’re noticing new or worsening fatigue, it’s worth tracking when it happens (after taking a dose, at a specific time of day, or throughout the day).
Does it get better over time, or does it worsen?
Often, side effects can improve after your body adjusts, especially in the first days to weeks. But if fatigue is severe, continues to worsen, or affects daily function, you should contact your prescriber. They may adjust the dose, change the timing of your dose, or switch medications depending on your situation.
Could your tiredness be from something else?
Yes. With depression or anxiety treatment, tiredness can come from several places, including:
- the illness itself (mood disorders can cause fatigue)
- changes in sleep from starting treatment
- other medications you take (many can cause sedation)
- medical issues like thyroid problems, anemia, or sleep apnea
A clinician can help sort out whether the timing lines up with starting or increasing Prozac.
When should you get urgent help?
Seek urgent care or contact emergency services if tiredness comes with signs of a serious reaction, such as:
- trouble breathing, swelling, or hives
- extreme agitation, confusion, high fever, or severe muscle stiffness
- fainting or severe weakness
What can you do to reduce fatigue from Prozac?
Practical steps that prescribers commonly consider include changing when you take the dose (morning vs. evening) and adjusting the dose. Don’t stop Prozac suddenly on your own, since that can cause withdrawal symptoms and can worsen mood symptoms.
If you tell me your Prozac dose and when you take it, plus when the tiredness started, I can help you think through whether the timing fits a Prozac effect and what to discuss with your prescriber.