Citalopram is an anti depressive medication that is part of a group of medications called SSRIs (selective serotonine reuptake inhibitors). When a patient withdraws from using and SSRI, she may experience some symptoms similar to those you've mentioned such as anxiety or tingling. Additionally, other symptoms of SSRI withdrawal might include like dry mouth, dizziness, sweating etc...These symptoms may last, individually, from one week to a month. You can try to regulate your blood pressure and the withdrawal effects of the medicament before going in for an operation. For additional consultation, you may seek help from a psychiatrist.