Effect of Low-Molecular-Weight Heparin on Potassium Homeostasis

Abstract

Background: Low-molecular-weight heparins (LMWHs) are being preferred to unfractionated heparin (UFH) because of their superior convenience and a comparable or slightly better toxicity profile. Whether LMWH has an inhibitory effect on aldosterone that causes hyperkalemia is yet uncertain. Methods: Twenty-eight patients (all male; mean age: 70 years, range 52–87 years) placed on LMWH therapy (40 mg subcutaneously every 12 h) for deep venous thrombosis prophylaxis after an operation were included in the study. Transtubular potassium concentration gradient (TTKG) was calculated 1 day prior to LMWH therapy and again after 4 days of treatment. Of the 28 patients enrolled in the study, we were able to calculate the TTKG in only 19 patients: 9 had a urinary osmolarity (either before or after LMWH therapy) less than the serum osmolarity, making the TTKG calculation unreliable. The Wilcoxon signed-rank test was used to analyze differences in the median serum potassium levels and TTKG before and after LMWH therapy. Results: All patients had adequate renal function (creatinine clearance >90 ml/min). Mean (± SD) serum potassium concentration before LMWH was 4.25 (± 0.40) mmol/dl. It increased to 4.35 (± 0.41) mmol/dl after initiating LMWH therapy (p = 0.09). Similarly, the mean (± SD) TKKG calculated was 5.52 (± 2.33) before and 5.97 (± 3.06) after 4 days of LMWH (p = 0.54). Conclusions: Unlike UFH, LMWH (Lovenox^®) in doses used for postoperative prophylaxis against deep venous thrombosis does not seem to have a significant effect on potassium homeostasis.

Effects of 8,000 IU aXa long-term prophylaxis with certoparin on the incidence of hyperkalemia in patients with coronary heart disease – a post-hoc analysis of the PARAT trial

“…Our results are in principal agreement with a prior observational study by Abdel-Raheem who reported no major increase in serum potassium with 2×40 mg enoxaparin per day [ 15 ]. It is in partial contrast, however, to a warning in the summary of product characteristics (SPCs) of enoxaparin and certoparin that potassium should be monitored in patients with increased serum potassium and those with a high risk.…”

“…Prolonged heparin application has been shown to result in a reduced width of the adrenal zona glomerulosa, an effect that appears to be more pronounced with UFH than LMWH [ 12 , 13 ]. Available studies on LMWH induced hyperkalemia have usually compared incidence rates with those observed with UFH [ 6 , 12 , 14 ] or were purely observational [ 7 , 15 ]. These studies suggested that hyperkalemia rates with LMWH were as high [ 6 ] or even lower [ 12 ] than those with UFH.…”

Diagnosis and treatment of low‐renin hypertension

“…Also, nonsteroidal anti‐inflammatory drugs (NSAIDs) and newer COX‐2 inhibitors inhibit the RAAS by suppressing intrarenal prostaglandin and renin secretion directly and by reducing sodium excretion, thus favouring volume expansion and aggravating hypertension 2 . Furthermore, unfractionated heparin (UFH) is a well known, potent inhibitor of aldosterone production; 47 notably, unlike UFH, low‐molecular‐weight heparins seem to lack effects on aldosterone production 48 . Third, a low‐renin/low‐aldosterone status may derive from a marked reduction in nephron number and function.…”

“…2 Furthermore, unfractionated heparin (UFH) is a well known, potent inhibitor of aldosterone production; 47 notably, unlike UFH, low-molecular-weight heparins seem to lack effects on aldosterone production. 48 Third, a low-renin/lowaldosterone status may derive from a marked reduction in nephron number and function. These conditions include diabetic nephropathy, chronic glomerulonephritis, congenital solitary kidney, unilateral nephrectomy or ageing.…”

Heparin-Induced Hyperkalemia in a Patient Diagnosed with Thyroid Storm

“…Recent studies have found that low-molecular-weight heparin and dabigatran can induce hyperkalemia in similar fashion, which makes clinical decisions to provide adequate antithrombotic therapy difficult. [16][17][18][19][20][21][22] This case exemplifies a confirmed case of HIH based on a low TTKG and a high score on the Naranjo probability scale, indicating a probable medication cause for hyperkalemia. 4 Additionally, our patient had normal potassium just prior to receiving UFH; hyperkalemia occurred early in his hospital stay; and alternative causes, including renal dysfunction, acidosis, and intake of potassium, were absent.…”