Antidepressants (cardiac Effects)

Question 1

TCAs

Answer 1

TCAs are associated with arrhythmia which is thought to result from blockade of cardiac sodium channels and variable activity at potassium channels.
ECG changes with tricyclic antidepressantsPR prolongation
QRS Prolongation
QTc prolongation

Brugada syndrome (genetic abnormality manifest only by aberrant cardiac conduction)😤😖😤😖😤😖 Lofepramine however does not share this effect and is considered low risk for arrhythmia.

Question 2

Other anyidepressants

Answer 2

Although there is evidence that venlafaxine is a sodium channel antagonist, arrhythmia is a rare occurrence even following massive overdose. Additionally, ECG changes are no more common than with SSRIs.

QTc changes are not normally seen with SSRIs at normal clinical doses (except for citalopram and escitalopram). Citalopram is linked to a risk of torsade de pointes and should be avoided if other QTc prolonging drugs are prescribed.

Moclobemide, citalopram, bupropion, lofepramine and venlafaxine should be used with caution (or avoided) in those at risk of arrthymia (previous MI, heart failure etc). TCAs (except lofepramine) are best avoided completely in patients at risk of arrthymia.

The arrhythmic potential for the antidepressants is dose related.