Reactions 1222 - 4 Oct 2008

SCitalopram/escitalopram

Hyponatraemia secondary to inappropriateantidiuretic hormone secretion in elderly patients:2 case reports

Two women developed hyponatraemia, secondary toinappropriate antidiuretic hormone secretion, duringtreatment with citalopram (patient 1) or escitalopram(patient 2) for depressive syndromes.

Patient 1, aged 65 years, had been receiving deflazacort, andfor the previous 15 days, citalopram 20 mg/day. She presentedwith a 5-day history of nausea, vomiting, a sensation ofinstability and headache. Laboratory tests revealed thefollowing levels: blood potassium 3.9 mEq/L, blood sodium119 mEq/L, urinary potassium 48 mEq/L, urinary sodium16 mEq/L, plasma osmolality 242 mOsm/kg and urinaryosmolality 287 mOsm/kg. Citalopram was stopped. Shereceived hypertonic serotherapy and in 48 hours her plasmasodium level was 135 mEq/L.

Patient 2, aged 81 years, was receiving lorazepam, and hadrecently begun receiving escitalopram 10 mg/day. After about12 days, she presented with apathy, asthenia and malaise.Physical examination showed mucocutaneous dehydration,skin pallor and a generalised motor deficit of 4/5. Laboratorytests revealed the following levels: blood potassium 4.1 mEq/L,blood sodium 116.7 mEq/L, plasma osmolality 247 mOsm/kg,urinary potassium 17.6 mEq/L and urinary sodium 32 mEq/L.Lorazepam and escitalopram were stopped and she receivedhypertonic serotherapy. In 48 hours she had a plasma sodiumlevel of 137 mEq/L.

Author comment: In the absence of diuretic treatment,and in view of the rapid return of blood sodium values tonormal, it was thought that the drug treatment could havebeen the trigger for both episodes of hyponatraemia. . . Inthe first case reported here, the administration of aglucocorticoid with a mild mineralocorticoid effect(deflazacort) could explain a urinary sodium level below 20mEq/L in the context of hyponatraemia secondary to elevatedADH excretion.Creus EJ, et al. Citalopram- and escitalopram-induced symptomatic hyponatremia.Endocrinologia y Nutricion 55: 178-180, No. 4, 2008 [Spanish; summarised from atranslation] - Spain 801117180

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Reactions 4 Oct 2008 No. 12220114-9954/10/1222-0001/$14.95 Adis © 2010 Springer International Publishing AG. All rights reserved