Which antidepressant class is most likely to cause hyponatremia via SIADH?

Which antidepressant class is most likely to cause hyponatremia via SIADH?

• A. SNRIs
• B. MAO inhibitors
• C. TCAs
• D. SSRIs

Answer: (D)

Hyponatremia from SIADH is a recognized adverse effect of some antidepressants, with the strongest link to selective serotonin reuptake inhibitors. SIADH happens when antidiuretic hormone is inappropriately released, causing the body to retain water and dilute serum sodium. Serotonin increases ADH release from the hypothalamus and posterior pituitary, and drugs that raise serotonin levels—namely SSRIs—are therefore more likely to provoke this mechanism. While other antidepressants such as SNRIs, TCAs, and MAO inhibitors can also contribute to hyponatremia, SSRIs have the most consistent association due to their serotonin-mediated stimulation of ADH. This risk is particularly notable in older adults or those with low baseline sodium, so monitoring sodium after starting or adjusting an SSRI is important.

Hyponatremia from SIADH is a recognized adverse effect of some antidepressants, with the strongest link to selective serotonin reuptake inhibitors. SIADH happens when antidiuretic hormone is inappropriately released, causing the body to retain water and dilute serum sodium. Serotonin increases ADH release from the hypothalamus and posterior pituitary, and drugs that raise serotonin levels—namely SSRIs—are therefore more likely to provoke this mechanism. While other antidepressants such as SNRIs, TCAs, and MAO inhibitors can also contribute to hyponatremia, SSRIs have the most consistent association due to their serotonin-mediated stimulation of ADH. This risk is particularly notable in older adults or those with low baseline sodium, so monitoring sodium after starting or adjusting an SSRI is important.