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Prozac Patient Tips

Written by C. Fookes, BPharm on Jun 15, 2016

How it works

  • Prozac is a brand (trade) name for fluoxetine. Experts believe fluoxetine's effects are due to its ability to block the reuptake of serotonin by nerves, leading to an increase in serotonin concentrations in the nerve synapse (space between two nerves). Its activity against other neurotransmitters is much less potent than other antidepressants.
  • Prozac belongs to a group of medicines called Selective Serotonin Re-uptake Inhibitors (SSRIs).


  • Used in the treatment of depression, obsessive-compulsive disorder, bulimia and panic disorder.
  • Less likely to cause weight gain than some other antidepressants; may cause weight loss.
  • Less likely to cause sedation than some other antidepressants; may cause insomnia (sleeplessness).


If you are between the ages of 18 and 60, take no other medication or have no other medical conditions, side effects you are more likely to experience include:

  • Headache, loss of energy, flu-like symptoms, nausea, diarrhea, weight-loss, abnormal bleeding, increased sweating or decreased libido. Anxiety, low sodium levels, allergic reactions (including rash) can also occur. May also affect heart rhythm and trigger angle-closure glaucoma.
  • As with other antidepressants, Prozac may increase the risk of suicidal thoughts or behavior, especially in children and young adults.
  • May impair judgement and affect ability to drive or operate machinery.
  • Interaction or over-dosage may cause serotonin syndrome (symptoms include mental status changes [such as agitation, hallucinations, coma, delirium], fast heart rate, dizziness, flushing, muscle tremor or rigidity and stomach symptoms [such as nausea, vomiting, diarrhea]). Another serious syndrome, called Neuroleptic Malignant Syndrome, has also been reported; symptoms include high body temperature, muscle rigidity, and mental disturbances. Discontinue Prozac immediately and seek urgent medical advice if this syndrome occurs.
  • May precipitate mania in people with undiagnosed bipolar disorder.
  • May interact with some other medications, including other antidepressants and other medications that increase bleeding risk. Avoid administration with pimozide or thioridazine.

Notes: In general, seniors or children, people with certain medical conditions (such as liver or kidney problems, heart disease, diabetes, seizures) or people who take other medications are more at risk of developing a wider range of side effects. For a complete list of all side effects, click here.

Bottom Line

Prozac is an antidepressant that is unlikely to cause drowsiness but may cause insomnia.


  • May be taken with or without food.
  • Morning dosages may decrease the risk of insomnia.
  • Be alert for changes in behavior including agitation, depressed mood, and suicide-related events and seek medical advice if changes are apparent.
  • Do not drive or operate machinery until full effects of Prozac are known as may impair judgement and affect ability to drive or operate machinery.
  • Seek urgent medical advice if symptoms consistent with serotonin syndrome (such as agitation, hallucinations, fast heart rate, dizziness, flushing, nausea, diarrhea) or Neuroleptic Malignant syndrome (including high body temperature, muscle rigidity, or mental disturbances) develop.

Response and Effectiveness

  • Peak plasma concentrations occur within six to eight hours of a single dose. A reduction in depressive or other symptoms may be noticed within two to four weeks; however, it may take up to six to eight weeks before full effects are seen.
  • Persists for a long time in the body, so it may take a while to see an improvement in mood or a reduction in side effects with dose changes.


Prozac (fluoxetine) [Package Insert] Revised: 02/2016 Accessed 15 June 2016 Dista Products Company

  • Remember, keep this and all other medicines out of the reach of children, never share your medicines with others, and use Prozac only for the indication prescribed.

  • Disclaimer: Every effort has been made to ensure that this information is accurate, up-to-date, and complete, but no guarantee is made to that effect. Drug information contained herein may be time sensitive. This drug information does not endorse drugs, diagnose patients or recommend therapy. It is an informational resource designed as a supplement to, and not a substitute for, the expertise, skill, knowledge and judgment of healthcare practitioners. The absence of a warning for a given drug or drug combination in no way should be construed to indicate that the drug or drug combination is safe, effective or appropriate for any given patient. does not assume any responsibility for any aspect of healthcare administered with the aid of this information. The information contained herein is not intended to cover all possible uses, directions, precautions, warnings, drug interactions, allergic reactions, or adverse effects. If you have questions about the drugs you are taking, check with your doctor, nurse or pharmacist.

Copyright 1996-2017 Revision Date: 2016-06-15 00:00:00