Diuretics and Na

Q: Which diuretics are more prone to induce hyponatremia? (select one)

A) Loop

B) Thiazide

Answer: B

Thiazides are notorious for causing hyponatremia, which typically occurs within the initial two weeks of intake. It can be a challenging situation for a clinician since patients with thiazide-induced hyponatremia are usually euvolemic clinically and exhibit many of the features of inappropriate ADH secretion. 

Hyponatremia rarely occurs with loop diuretics. This is because the inhibition of sodium chloride transport in the loop of Henle impairs the generation of the countercurrent gradient and, therefore, limits the ability of ADH to promote water retention. However, this should not be taken as a universal rule, as patients with CHF or cirrhosis may develop hyponatremia, as these disease processes are prone to cause hyponatremia or may be subject to over-diuresis.

#nephrology

#electrolytes

#pharmacology

References:

1. Filippone EJ, Ruzieh M, Foy A. Thiazide-Associated Hyponatremia: Clinical Manifestations and Pathophysiology. Am J Kidney Dis. 2020 Feb;75(2):256-264. doi: 10.1053/j.ajkd.2019.07.011. Epub 2019 Oct 9. PMID: 31606239.

2. Burst V, Grundmann F, Kubacki T, Greenberg A, Becker I, Rudolf D, Verbalis J. Thiazide-Associated Hyponatremia, Report of the Hyponatremia Registry: An Observational Multicenter International Study. Am J Nephrol. 2017;45(5):420-430. doi: 10.1159/000471493. Epub 2017 Apr 19. PMID: 28419981; PMCID: PMC5452281.