In few cases, pure citalopram overdose at doses above 600 mg showed electro-cardiographic changes with prolonged QT intervals and sinus bradycardia gradually resolving within 12-24 hours after intoxication. We report on a 32-year-old patient with borderline personality disorder (BPD) who ingested a total of 800 mg citalopram to attempt suicide due to an interpersonal disappointment. She developed severe sinus bradycardia with a minimal pulse rate of 41/min within about 4 hours after intoxication lasting up to six days during intensive care unit (ICU) treatment. Further, hypotension and syncopes occurred. No QT interval prolongations were recorded. To our knowledge, this is the first case report of pure citalopram overdose-induced long-lasting sinus bradycardia associated with severe hypotension and intermittent syncopes that required therapy with a temporary pacemaker.