Posted by shantie on August 20, 2000, at 2:19:48
In reply to Re: Celexa » Nanci, posted by Cam W. on August 18, 2000, at 23:17:06
> Nanci - As with any antidepressant it takes a minimum of 2 weeks to notice any effect and 4 to 8 weeks (or more) for full effect. I like to say that in 2 weeks others notice a lifting of your depression and in 4 weeks you begin to notice the change.
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> While both of these drugs are SSRIs (selective serotonin reuptake inhibitors) the main differences between Prozac™ (fluoxetine) and Celexa™ (citalopram) are as follows:
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> 1) - the half-life (the time it takes for half of the drug to leave the body) of Prozac and it's main active metabolite is about 100 hours, while the half-life of Celexa and it's active (but less potent) metabolites is about 37 hours. This means that Celexa does not accumulate in the body as readily as Prozac, so if you have to switch to a different class of antidepressants, it can be done quicker from Celexa (2 week washout) than from Prozac (5 week washout). Switching within the SSRI class can be done without a washout period.
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> 2) - Prozac inhibits a certain portion of a liver enzyme system called the cytochrome P450 system. This system is involved in the metabolism of many different drugs. The inhibition of a certain portion of this enzyme system can cause an increase in the blood concentration of certain other drugs. This is called a drug-drug interaction and the dose of the other drug may need to be modified. This enzyme inhibition is not caused by Celexa to any appreciable extent, so Celexa has really no significant drug interactions other than with the monoamine oxidase inhibitor antidepressants (MAOIs).
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> 3) - Celexa affects fewer receptor systems in the body than Prozac. Even though Prozac is called a selective serotonin reuptake inhibitor it affects other receptors as well as the serotonin reuptake receptor. In essence, SSRIs block the reuptake of the neurotransmitter serotonin back into the nerve cell from which it was released, leaving more serotonin in the synaptic gap between nerve cells, enhancing the electrical signals from one nerve cell to another. Although a lack of serotonin is not the cause of depression, increasing it's levels in the body seems to resolve the depressive symptoms in a majority of subtypes of depressions. This is probably not be the full mechanism of action of SSRI antidepressants, but it is a reproduceable feature of them. By affecting more than just the serotonin reuptake receptor (eg certain other serotonin receptors, norepinephrine reuptake receptors, etc.) Prozac supposedly has more side effects (and possibly therapeutic effects, in some cases) than Celexa, which only really blocks the serotonin reuptake receptor. Celexa is said to be a "cleaner" (more selective) drug than Prozac.
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> 3) - Prozac can be augmented by lithium when it doesn't fully relieve the depressive symptoms, while augmenting Celexa with lithium causes no enhancement of antidepressant effect.
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> These are some of the main differences between Prozac and Celexa. I have probably missed some, but others on the board will fill in the gaps. Even though SSRIs are thought to have similar actions in depression, people do have different responses to the different SSRIs (one SSRI may not resolve a person's depressive symptoms, while another will).
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> Is Celexa right for you? Unfortunately, we can only roughly estimate if a certain antidepressant will work for a certain person. You have to give each antidepressant you try an adequate trial period (usually 8 weeks). Stick it out for the 8 weeks and see if it works, unless your doctor decides differently.
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> Will Serzone™ (nefazodone) work for you? Again, the only way to know is to give it an 8 week trial.
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> I have seen several people who have stopped responding to Prozac (on this board we call it "poop-out") and have been tried on Celexa and it has worked. This is not true for everyone and I don't know what the percentages of responders are. As we say, "Your Mileage May Vary".
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> As for the energy issue, SSRIs usually are not that sedating in most people, but when they are you usually see it with Prozac, rather than with Celexa. Your lack of energy may be partially a symptom of depression, rather than fully due to the Prozac. One good non-drug way of increasing energy is to exercise regularily. There are many drugs, including some antidepressants that can increase energy (eg Wellbutrin™ - bupropion), but they may not work for your specific type of depression. Ask your doctor about other alternatives.
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> Sorry that this was so long winded, but once I started, I couldn't stop (sort of like potato chips).
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> Hope this helps - CamCam since you seem to have a pretty good understsnding of these drugs....does celexa's side effects really make you gain weight and have loss of hair? I am on 60mgs of ritalin and 300mgs of WB-i was supposed to start taking 20mgs of celexa a few days ago but i am afraid, especially after taking effexor for 3 months and gaining 16lbs. i dint really notice too much difference to me it wasnt worth it ......
poster:shantie
thread:43277
URL: http://www.dr-bob.org/babble/20000811/msgs/43361.html