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How to prescribe loop diuretics in oedema

BMJ 2019; 364 doi: (Published 21 February 2019) Cite this as: BMJ 2019;364:l359

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Re: How to prescribe loop diuretics in oedema

Dear Drs. Loke and Squire,

We very much appreciate your careful reading and thoughtful response to our article “How to prescribe loop diuretics in oedema”. You raise the point that “as needed dosing” is potentially problematic in certain populations, an assertion with which we completely agree; we recommend this approach only for patients who are capable of employing it. There are as yet no randomized trials showing incremental benefits with this approach, although our clinical experience has been excellent. We took great care to indicate the quality of evidence and the source of our recommendations here and elsewhere. We also agree that some patients may require maintenance dosing, although in our experience this can be a thiazide (we recommend chlorthalidone), with as-needed use of loop diuretics. While under-diuresis is a legitimate concern, we also commonly see heart failure patients admitted to the hospital with significant hypovolemia and renal failure from overly-aggressive diuresis. Given the all-or-none nature of the loop diuretic response, there are no effective methods, other than decreased dosing frequency (either as needed, or scheduled - such as every other day or every third day, etc) to reduce the potency of loop diuretics and to therefore avoid complications of their use.

We agree that the evidence supporting the advantages of torsemide over furosemide is not of the highest standard, which led us to include the details behind our reasoning. However, the results of head-to-head comparisons, despite their limitations, consistently point in the same direction (other than the post-hoc re-analyses by Mentz that you referenced), favoring torsemide over furosemide. While the evidence is not conclusive, it is very compelling, and at a minimum, it certainly does not support the widespread common-use preference of choosing furosemide as the first-line drug in treating oedema.

We are very much looking forward to more definitive research in this area; for such a common condition with life-threatening complications, it is shockingly under-analyzed, in our opinion. Until definitive data are published, we recommend making the most informed decisions possible using the best available evidence, despite its limitations. We agree that many guidelines are not yet in alignment with what we have presented as the best available evidence, and are hoping that this article - and others like it - may have an impact in that direction.

Competing interests: No competing interests

08 March 2019
Steven D Anisman
Bennington , VT, USA