What Is the Difference between Fluoxetine and Citalopram?

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  • Written By: S. Berger
  • Edited By: Shereen Skola
  • Last Modified Date: 28 January 2020
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Fluoxetine and citalopram are both medications that are used to treat depression, along with certain other mental disorders. They are both classified as selective serotonin reuptake inhibitors (SSRIs), a class of drugs that increases serotonin levels in the brain. Serotonin is a chemical produced in the brain that influences mood, and increasing its levels may help reduce depressive symptoms.

Despite their chemical similarities, these medications have several important differences that impact when and how they are used. Studies have shown that both medications are about equally effective in their ability to treat depression. Citalopram begins to alleviate depression symptoms somewhat more quickly, however.

Another important difference between fluoxetine and citalopram relates to which disorders they are used to treat other than depression. Fluoxetine is sometimes combined with another drug, olanzapine, to treat bipolar disorder, but citalopram is not usually used for this purpose. Some of the unique disorders that citalopram may be used to treat include body dysmorphic disorder, anxiety, pain originating in the nerves, and, occasionally, premature ejaculation.

Both fluoxetine and citalopram are different in their chemical structures, and respond differently to proteins in the brain. Polyglycoprotein (Pgp) is a transport protein used to remove compounds from the brain. This protein can move citalopram out of the brain in some individuals, making this substance less effective for certain people. Pgp does not affect fluoxetine, however, which indicates that this medication would still be helpful even in people with this alternate form of Pgp.


Side effects of fluoxetine and citalopram are fairly common for all SSRIs, and include nausea, indigestion, and headaches. There are some slight differences in these side effects based on slight chemical differences between medications. Citalopram can affect levels of dopamine, a neurotransmitter chemical involved in mood and reward functions. This effect, which fluoxetine does not have, means that citalopram may sometimes cause patients to have a lack of emotion, or become less likely to openly show emotion.

Fluoxetine and citalopram differ in their half lives, or the time that it takes for the body to process half of a medication after it is taken. The half life of fluoxetine is around four to six days when taken daily, but citalopram's half life is only 36 hours. This can effect how doctors take patients off of these medications, since abruptly stopping SSRI treatment can result in unpleasant and dangerous adverse effects. A patient seeking to stop taking citalopram may be switched from that medication to fluoxetine by a doctor first, since the longer half life of the latter drug allows for a more gradual taper, with fewer adverse effects.


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Post 5

Sometimes the effectiveness of an antidepressant in relatives can be an indicator of how related family members might respond to similar meds. If it works for your cousin, there may be a genetic similarity in how you would respond.

Post 4

I take Klonopin, to me a miracle drug compared to Xanax as the withdrawal symptoms are far less severe. The problem is, like Xanax, its street popularity has made it an act of congress just to get a prescription now, and the last few doctors seem to think that Celexa, or Prozac, or Zoloft, will do what Klonopin does. That is a lie. Even if added with Klonopin, I have found all thre only reverse the positives Klonopin offers to me: relief of anxiety of many kinds, a better handle on depression, and the ability to relax and sleep better. The others only killed my appetite, destroyed my sex life and robbed me of sleep every night.

I am not

a doctor, but I think the answer for me was an increased dose of Klonopin. In Texas, I was given a script for 2 mgs twice daily. In North Carolina, I can only get 1 mg twice daily and the choice of the SSRI's I mentioned above. I have told every doctor I felt my best on the 2 mg twice daily regimen, but due to the new laws regarding benzodiazepines, no doctor will go above 1 mg. Instead, they offer anti depressants which, for me, seem to counter the very things they are being prescribed to me for. I have chosen not to take Prozac, as it appears to be quite similar to Celexa, and again I don't feel like losing sleep, losing sex, losing my appetite and the other side effects from taking Naproxen and Tramadol, since doctors are also afraid to prescribe the other drug that helps me with my chronic back pain: Soma.

When I was on both Klonopin and Soma, I felt the best I've felt in years. I have also tried Depakote, Effexor, and more, all of which failed miserably. So now I have a stockpile of Zoloft, Celexa and Prozac because I want to see what my doctor says next month at my appointment when I lie and say I'm taking the Prozac and having the same bad side effects as I was with Celexa, which are plainly posted on the info sheet attached with the medication.

It is causing me anxiety which I'm supposedly being treated for having to live month to month on a refill. This is stupid to me and quite counterproductive to my treatment for anxiety. I just wish I could go back to the 2 mgs twice a day, and the 2 350 mgs of soma and get a 1 year script so I don't have anxiety or pain having to grovel for a lousy one month prescription. I'm not a drug dealer or a drug abuser. I am a regular person just trying to live a more normal life but the dealers and abusers are ruining it all for the people like me.

Post 3
I'll take fluoxetine over citalopram any day. Fluoxetine has been around for a while and is safe to use even in teenagers. Citalopram is a fairly new drug and its long-term effects are not known.
Post 2

@simrin-- I'm not a doctor and I think your doctor should decide what medication is best for you because all of us are dealing with slightly different issues.

Having said that, I have used both fluoxetine and citalopram in the past. I have general anxiety disorder but I was mistakenly diagnosed with depression several times. But anxiety and depression frequently go hand in hand and it can be difficult to figure out which is the main problem in someone.

Fluoxetine is mainly used for depression and it did not help my anxiety either. Citalopram on the other hand, is firstly an anxiety medication and it definitely helped me. In fact, citalopram got rid of my anxiety all together.

I should also mention that it can take selective serotonin reuptake inhibitors (SSRIs) at least six months to show effects. Both fluoxetine and citalopram are SSRIs. So you should probably try your medication for longer before deciding that it doesn't work.

Post 1

I have anxiety and my doctor prescribed me fluoxetine. I've been taking it for a few weeks now but aside from making me sleepy all the time, it hasn't helped with my anxiety at all.

My cousin is on citalopram and was telling me that it has helped her a lot. Does citalopram work for anxiety or is it like fluoxetine in that regard?

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