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Cardiac effects of different tricyclic antidepressant drugs
Insights
Tricyclic antidepressants can increase heart rate and slow atrioventricular conduction. Overdoses frequently cause distal conduction defects, but therapeutic doses rarely impair heart conduction.
Area of Science:
- Cardiology
- Pharmacology
- Psychiatry
Background:
- Tricyclic antidepressants (TCAs) are widely used for depression.
- Cardiac side effects of TCAs require thorough investigation.
Purpose of the Study:
- To review the cardiac effects of tricyclic antidepressants.
- To investigate atrioventricular conduction in patients treated with TCAs.
Main Methods:
- His bundle electrocardiography was used.
- Studied ambulant patients and those with TCA overdose.
- Included animal experiments for comparative analysis.
Main Results:
- TCAs significantly increased heart rate and atrioventricular conduction times.
- Distal conduction defects were common in TCA overdose, except with doxepin.
- Impaired conduction occurred rarely at therapeutic TCA doses.
Conclusions:
- TCAs can affect cardiac conduction, particularly at high doses.
- Doxepin may have a different cardiac safety profile compared to other TCAs.
- Monitoring cardiac function is important for patients on TCAs.
Abstract:
The effects of tricyclic antidepressants on the heart are reviewed. Statistically significant increases in heart rate and in atrioventricular conduction times were found following the administration of tricyclic drugs to 32 depressed patients. The method of His bundle electrocardiography was used to study atrioventricular conduction in ambulant patients and in patients admitted after an overdose of tricyclic antidepressant drugs. Distal conduction defects were frequently found in patients following tricyclic overdosage, but these were not seen with doxepin overdosage. Impaired distal conduction was also found in occasional patients on therapeutic doses of tricyclic drugs. Some animal experiments giving similar results to the above clinical findings are also described. The clinical implications of these findings are discussed.