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Citalopram-induced bradycardia and presyncope
G K Isbister1, F H Prior, A Foy
1Department of Clinical Toxicology and Pharmacology, Newcastle Mater Misericordiae Hospital, Locked Bag 7, Hunter Region Mail Centre, NSW 2310, Newcastle, Australia. gsbite@bigpond.com
The Annals of Pharmacotherapy
|January 17, 2002
Summary
Therapeutic citalopram use can cause symptomatic bradycardia and hypotension, even at low doses. This case highlights the importance of monitoring heart rate and blood pressure in patients, especially the elderly, during citalopram therapy.
Area of Science:
- Pharmacology
- Cardiology
- Clinical Toxicology
Background:
- Selective serotonin reuptake inhibitors (SSRIs) like citalopram are widely prescribed for depression and anxiety.
- While generally safe, SSRIs can have cardiovascular side effects, particularly in vulnerable populations.
- Previous reports have linked citalopram to QT prolongation and arrhythmias, primarily in overdose scenarios.
Observation:
- A 60-year-old woman developed symptomatic bradycardia (heart rate 39 bpm) and hypotension (BP 105 mmHg) after two weeks of therapeutic citalopram 20 mg/day.
- The patient experienced a presyncopal episode, necessitating hospitalization for cardiac monitoring.
- Discontinuation of citalopram led to the resolution of bradycardia and hypotension within 48 hours, with no other cause identified.
Findings:
- This is the first detailed case report of symptomatic bradycardia and hypotension associated with a low therapeutic dose (20 mg/day) of citalopram.
- Manufacturer data indicates bradycardia is an infrequent adverse effect (0.1-1%), with no prior reports to ADRAC or the manufacturer in postmarketing surveillance.
- The observed sinus bradycardia is distinct from the QT abnormalities typically seen with citalopram overdose, as no QTc prolongation was noted in this case.
Implications:
- Citalopram should be used with caution in elderly patients and those with pre-existing heart conditions.
- Close monitoring of heart rate and blood pressure is recommended during the initial week of citalopram therapy and following any dose adjustments.
- This case underscores the potential for citalopram to cause significant bradycardia at therapeutic doses, necessitating increased clinical vigilance.