Taking citalopram 20mg for depression and i've ran out is it okay to take a different anti depressant same dose until i go to the doctors too get more?

Not necessarily: Not really. Celexa & Lexapro (escitalopram) are identical in terms of the active ingredient. However there are differences with other antidepressants - especially if they are not selective serotonin reuptake inhibitors. If you call the doctor's office, they will sometimes order you a temporary refill at a pharmacy to get you through to your next appt date. Good luck.