I got the following information from the celexa.com website. I hope you find it useful.
Celexa is well tolerated by many people. The most frequent side effects reported with Celexa are nausea, dry mouth, drowsiness, insomnia, increased sweating, tremor, diarrhea, and problems with ejaculation.
People taking Celexa generally do not suffer from insomnia, agitation, nervousness, or anxiety any more than people not taking Celexa. Furthermore, Celexa has not been associated with clinically significant weight changes.