Background and Importance The correlation between psychotropic drugs and iatrogenic syndrome of inappropriate antidiuretic hormone secretion (SIADH) has been well documented. In regards to anxiolytics and hypnotic drugs, however, a recent expert consensus finds only low-level evidence supporting the relationship between benzodiazepines and SIADH. In this report we present a case of patient with diagnosed alprazolam-induced SIADH.

Aim and Objectives A 67 year-old woman was diagnosed with SIADH possibly induced by alprazolam benzodiazepine. The patient, with a long history of anxiety syndrome, was treated with alprazolam 0.25 mg 3 times daily for more than 10 years. The patient also suffered from Hashimoto’s thyroiditis, pulmonary arterial hypertension, paroxysmal atrial fibrillation, mitral valvuloplasty, Gilbert’s syndrome and underwent polypharmacy treatment with furosemide 25 mg, rivaroxaban 20 mg, bisoprolol 5 mg, ramipril 5 mg, amlodipine 20 mg, atorvastatin 10 mg and cholecalciferol 10.000 UI/ml.

Material and Methods In 2020, the patient attended the emergency department after syncope and diarrhoea. Blood tests revealed sodium levels of 126 mmol/L. Furosemide was immediately suspended and sodium with inulin supplementation was initiated. The subsequent follow-up tests excluded hypocorticism or thyroid dysfunction; copeptin and sodium and potassium excretion levels were all in range; all other possible causes were excluded. Due to the anxiety syndrome, benzodiazepine therapy was not discontinued but alprazolam was replaced with bromazepam 1.25 mg twice daily.

Results Since last check-ups, the patient has been presenting stable mild hyponatremia (around 130 mmol/L) and is continuing daily oral sodium and inulin supplementation. Periodic electrolyte tests and monitoring for symptoms such as confusion, psychomotor retardation, nausea or vomiting are recommended at every visit.

Conclusion and Relevance The patient presented in this case report was diagnosed with an alprazolam-induced SIADH after differential diagnosis. Risk factors known to potentially cause SIADH, such as age >=60 years, female gender, polypharmacy and medical comorbidities, all present in the described patient, had to be taken into consideration for diagnosis. Benzodiazepine-induced SIADH could be considered in case of hyponatraemic patients presenting underlying risk factors and in the absence of other clinical causes.

References and/or Acknowledgements 1. Pinkhasov A, et al. Management of SIADH-related hyponatremia due to psychotropic medications -An expert consensus from the Association of Medicine and Psychiatry. J Psychosom Res. 2021;151:110654.

Conflict of Interest No conflict of interest.