There are no official guidelines to assist in answering this question. I will search for relevant research papers instead.
From the FDA Drug Label
Hyponatremia may occur as a result of treatment with SSRIs and SNRIs, including Escitalopram. In many cases, this hyponatremia appears to be the result of the syndrome of inappropriate antidiuretic hormone secretion (SIADH), and was reversible when Escitalopram was discontinued. Cases with serum sodium lower than 110 mmol/L have been reported Elderly patients may be at greater risk of developing hyponatremia with SSRIs and SNRIs. Also, patients taking diuretics or who are otherwise volume depleted may be at greater risk [see Geriatric Use (8. 5)].
Yes, Escitalopram (Lexapro) is associated with hyponatremia, which may be due to the syndrome of inappropriate antidiuretic hormone secretion (SIADH) and is more common in elderly patients and those taking diuretics or who are volume depleted 1.
From the Research
Association between Escitalopram and Hyponatremia
- Escitalopram, an SSRI, has been associated with hyponatremia in several studies 2, 3, 4, 5, 6.
- A retrospective observational cohort study found that escitalopram was associated with a higher overall risk of hyponatremia compared to sertraline, with a hazard ratio of 1.16 [1.01-1.33] 2.
- Case reports and observational studies have also reported hyponatremia associated with escitalopram use, with the incidence varying from 0.5% to 32% 3.
- The mechanism by which escitalopram causes hyponatremia is thought to be secondary to the development of syndrome of inappropriate antidiuretic hormone secretion (SIADH) 3, 4, 6.
Risk Factors and Management
- Risk factors for the development of hyponatremia with escitalopram include older age, female gender, concomitant use of diuretics, low body weight, and lower baseline serum sodium concentration 3.
- Treatment of hyponatremia associated with escitalopram includes water restriction and mild diuresis with a loop diuretic, with more severe cases requiring higher doses of loop diuretics and hypertonic saline 3.
- Regular monitoring of serum sodium levels is crucial when administering escitalopram, especially in elderly patients or those with other risk factors for developing hyponatremia 5, 6.