Effects of antidepressants on the HPA axis

Drug groupDrugProperties
Tricyclic antidepressantsImipramine

Reduced HPA axis responsiveness over 6 weeks [179]

No change in cortisol levels over 4 weeks [180]

NortriptylineReduced ACTH and no change in cortisol over 4 weeks [182]
AmitriptylineNo effects on circadian variations in cortisol over 6 weeks [183]
SSRIsFluoxetineReduced ACTH and no change in cortisol over 4 weeks [180, 181]
Citalopram

Transient increase in morning cortisol after 6 days [187]

Reduced HPA axis responsiveness over 4 weeks [188]

Escitalopram

Transient stimulation of cortisol response to dexamethasone at 1 week [184, 185]

No effects on diurnal secretion of ACTH or cortisol over 8 weeks [186]

FluvoxamineNo effects on circadian variations in cortisol over 6 weeks [183]
SNRIsVenlafaxineNo effects on cortisol over 4 weeks [190]
Other antidepressantsMirtazapineTransient increase in morning cortisol after 1 week [189]