Which antidepressant may cause hyponatremia in a client?

Paroxetine is known to be associated with the risk of hyponatremia, particularly in older adults. This phenomenon may occur due to the drug's impact on the body's balance of sodium, which can lead to a decreased serum sodium concentration. Hyponatremia can result in various neurological symptoms, ranging from mild confusion to more severe conditions such as seizures or coma.

The pharmacological action of paroxetine, an SSRI (selective serotonin reuptake inhibitor), can contribute to the release of antidiuretic hormone (ADH), which may result in the body retaining excess water. This water retention dilutes the sodium levels in the bloodstream, leading to hyponatremia.

While other SSRIs like citalopram and fluoxetine may have some risk for hyponatremia, paroxetine has a more established link to this side effect based on clinical observations and studies. Venlafaxine, while having its own side effects, is an SNRI (serotonin-norepinephrine reuptake inhibitor) and does not have the same significant association with hyponatremia as paroxetine. Therefore, paroxetine is recognized in clinical practice for its potential to cause this electrolyte imbalance.