Like any antidepressant, not everyone responds or tolerates any given medication. Celexa may cause suicidal thoughts or ideation. Citalopram is an antidepressant in a group of drugs called selective serotonin reuptake inhibitors. Celexa causes less drug interactions, you should always let your doctor know what other medications you are taking. Do not stop using Celexa without first talking to your doctor. You must wait at least 14 days after stopping an MAO inhibitor.