What does it mean " prozac (fluoxetine) is activating" compared to other ssri?

Stimulating: Ssris are all similar in how they work, but they vary in how "activating" or "stimulating" they are. A more activating ssri like Prozac can be caffeine-like: gives more energy but makes it hard to sleep. While all ssris can help anxiety, i tend to prefer less activating ones for this problem, as activation may temporarily worsen the feeling of anxiety. Less activating: paxil, (paroxetine) lexapro, celexa.

More "get up and go": Prozac (fluoxetine) tends to have a higher incidence of being activating as a side effect. This means that the Prozac (fluoxetine) may help one have more "get up and go". The opposite of this would be a medicine that tends to be more "calming" or sedating. Keep in mind that all of these medications work in conjunction with your individual body chemistry, and this will dictate if Prozac (fluoxetine) is more activating or calming.

Activating: When i said that Prozac (fluoxetine) can be a little more activating in some people, i meant that for some (not all) it can be more energizing esp. If depression has been making you feel more tired. Both Prozac (fluoxetine) and Celexa can help depression & anxiety, though. Some people also may feel jittery beginning either of these; possibly more often with prozac (fluoxetine). If it happens, this effect may dissipate with time.