Adverse effects of propafenone after long-term therapy with the addition of citalopram

Background: Propafenone, a class IC antiarrhythmic, and citalopram, a selective serotonin reuptake inhibitor (SSRI), are widely used in older patients. Although a potential interaction between propafenone and SSRIs has been noted, a MEDLINE search revealed no published reports of an interaction between propafenone and citalopram. Objective: The goal of this article was to describe a potential drug-drug interaction between propafenone and citalopram, which caused symptoms of propafenone adverse effects. Case summary: An 80-year-old white female, followed up at the Memory Clinic for mild cognitive impairment, had been taking propafenone 900 mg/d for >10 years for Paroxysmal atrial fibrillation without adverse effects. Three months after starting citalopram, she experienced episodes of chest tightness and dizziness. The episodes became more frequent in the following months, causing several falls and requiring visits to the emergency department, but no acute coronary event was diagnosed. She was started on amlodipine 2.5 mg orally once daily, a nitroglycerin patch (0.4 mg/h), and warfarin 5 mg orally once daily. After one fall, the patient became delirious. Amlodipine and the nitroglycerin patch were discontinued and propafenone decreased to 450 mg/d; citalopram was continued at 20 mg/d. The patient recovered well, both cognitively and physically, and did not have any further symptoms in I year of follow-up. Results of coronary investigations were negative. Conclusions: This is the first report of a possible interaction between propafenone and citalopram, which caused propafenone adverse effects (eg, dizziness, falls) and mimicked coronary artery disease.