Recurrent hyponatremia after substitution of citalopram with duloxetine

Factors Associated with Hyponatremia in Patients Newly Prescribed Citalopram: A Retrospective Observational Study

Background

Hyponatremia is a common and under-recognized adverse drug reaction of selective serotonin re-uptake inhibitor (SSRI) antidepressants. Despite its clinical importance, there are few large-scale studies on the factors associated with hyponatremia.

Objective

The aim of this study was to determine the incidence of hyponatremia and to identify patient factors associated with hyponatremia in a large, population-based cohort initiating new prescriptions for citalopram.

Methods

We included all patients with a new prescription for citalopram during 2010–2017, inclusive, with baseline and post-initiation serum sodium values available. Data were obtained from an Alberta Health Pharmacy database to identify new citalopram prescriptions. Laboratory values for patients with new prescriptions were obtained from linked Calgary Laboratory Services data. Incident hyponatremia was defined as serum sodium level < 135 mmol/L, following prescription initiation. Associations were determined by performing Cox regression with time-varying covariate analysis, with the development of hyponatremia as the dependent variable.

Results

A total of 19,679 patients with new prescriptions were identified; 12,842 females and 6837 males. The mean age was 55.48 years (SD 21.35). Of these patients, 3250 (16.5%) developed hyponatremia, 1996 (15.5% of) females and 1254 (18.3% of) males (p = 0.002). Cox regression showed significant associations of hyponatremia with lower baseline sodium (HR 0.788), older age (HR 1.029), thiazide diuretic use (HR 1.141), and male sex (HR 1.168). Pharmaceutical manufacturer or strength of citalopram did not have significant effects on the development of hyponatremia.

Conclusion

This study provides additional data on the predictors of hyponatremia among patients initiating citalopram therapy. We report a 16.5% incidence of hyponatremia after starting citalopram treatment, and significant new findings include a higher incidence in males. This is the first published incidence of hyponatremia following the initiation of citalopram treatment across all ages in Canada.

Rapid-onset hyponatremia and delirium following duloxetine treatment for postherpetic neuralgia: Case report and literature review

RATIONALE

Hyponatremia following duloxetine treatment has been reported in patients with major depressive disorder, fibromyalgia, diabetic neuropathy, or sciatic pain. The manifestations of duloxetine-induced hyponatremia are varying in different individuals. The overall prognosis for this type of hyponatremia is favorable if properly managed.

PATIENT CONCERNS AND DIAGNOSES

Herein, we reported rapid-onset hyponatremia and delirium in an older patient after 2 doses of duloxetine, which was used to control his postherpetic neuralgia. Laboratory examinations revealed a rapid decline in serum sodium level and indicated the possibility of syndrome of inappropriate antidiuretic hormone (SIADH).

INTERVENTIONS

Discontinuation of duloxetine, restriction of water intake, and intravenous supplement of normal saline were adopted to manage the hyponatremia.

OUTCOMES

Serum concentration of sodium gradually normalized following aforementioned strategies.

LESSONS

Special attention to the electrolyte abnormality is recommended in old patients undergoing duloxetine treatment.

Appropriate prescribing and important drug interactions in older adults

Polypharmacy, specifically the overuse and misuse of medications, is associated with adverse health events, increased disability, hospitalizations, and mortality. Mechanisms through which polypharmacy may increase adverse health outcomes include decreased adherence, increased drug side effects, higher use of potentially inappropriate medications, and more frequent drug-drug interactions. This article reviews clinical problems associated with polypharmacy and presents a framework to optimize prescribing for older adults.

Antidepressants and the risk of hyponatremia: a class-by-class review of literature

BACKGROUND

Antidepressant-induced hyponatremia can cause significant morbidity and mortality. It is mostly associated with the use of selective serotonin reuptake inhibitors (SSRIs), but its frequency and class specificity are uncertain.

OBJECTIVES

To determine the relationship between hyponatremia and antidepressants and to define the incidence and odds ratios for antidepressant classes.

METHODS

A review of the literature prior to March 2013 was performed using Web of Science and PubMed by employing combinations of search strings "antidepressants" and antidepressant class and generic drug names with "hyponatr(a)emia," "SIADH," or "inappropriate ADH."

RESULTS

Overall, 21 effect studies and more than 100 case reports were considered, most concerning SSRIs. Because of variations in study designs, populations, and cutoff values, incidence rates diverged between 0.06% and 40% for SSRIs and 0.08% and 70% for venlafaxine. Although based on less solid evidence, incidence figures for mirtazapine and tricyclic antidepressants were lower. Regarding classes, odds ratios for SSRIs (1.5-21.6) were consistently higher than for tricyclic antidepressants (TCAs) (1.1-4.9). The risks associated with monoamine oxidase inhibitors, reboxetine, and bupropion could not be established owing to insufficient information. Patient risk factors included older age (odds ratios = 6.3) and concomitant use of (thiazide) diuretics (odds ratios = 11.2-13.5).

CONCLUSION

Hyponatremia is a potentially dangerous side effect of antidepressants and is not exclusive to SSRIs. Current evidence suggests a relatively higher risk of hyponatremia with SSRIs and venlafaxine, especially when combined with patient risk factors, warranting clinicians to be aware of this complication. The risks associated with mirtazapine are moderate, supporting this antidepressant as an alternative treatment for patients with (an increased risk of) hyponatremia.

Rapid-onset hyponatremia induced by duloxetine in a middle-aged male with depression and somatic symptoms

Duloxetine is a relatively balanced selective serotonin and noradrenaline reuptake inhibitor. We report a case of hyponatremia induced by duloxetine developed rapidly after starting the medication in a middle-aged male with multiple somatic symptoms and depression. Two days after discontinuation of duloxetine and management with hypertonic saline as well as fluid restriction, the serum sodium level normalized. The patient had two risk factors for developing hyponatremia, such as severe body weight loss and pneumonia. Therefore, when treating patients with depression and somatic symptoms, especially with risk factors for developing hyponatremia, close monitoring for clinical and laboratory evidence of hyponatremia may be essential.

Symptomatic hyponatremia during glomerular filtration rate testing

Hyponatremia affects nearly one in five of all hospitalized patients. Severe hyponatremia is associated with significant morbidity and mortality, and is therefore important to recognize. Prior reports have linked duloxetine with hyponatremia, but it is uncommon. In this case report, we describe a research subject taking duloxetine who developed severe symptomatic hyponatremia during glomerular filtration rate testing despite having undergone such testing uneventfully in the past.