Role of fludrocortisone in the management of tacrolimus-induced hyperkalemia in a renal transplant recipient

Fludrocortisone Among Adult Renal Transplant Recipients With Persistent Hyperkalemia: Single-Center Experience

OBJECTIVES

Calcineurin inhibitors are the cornerstone of immunosuppression following solid-organ transplant. However, hyperkalemia may occur by multiple mechanisms affecting potassium in the distal tubule. Hyperkalemia is commonly observed in renal transplant recipients, and it is dose-dependent. Here, we evaluated the impact of fludrocortisone in the management of calcineurin inhibitor-induced hyperkalemia after renal transplant.

MATERIALS AND METHODS

We evaluated newly transplanted patients who developed hyperkalemia or those with hyperkalemia who attended our outpatient renal transplant clinic (Hamed Al-Essa Organ Transplant Center, Kuwait). Clinical and laboratory parameters were collected before starting fludrocortisone (baseline values) and then at 1, 2, 4, and 8 weeks. Drug history was assessed, with any drugs that could induce hyperkalemia being discontinued (such as spironolactone); otherwise, essential drugs like prophylactic agents (sulfamethoxazole-trimethoprim) were maintained. Oral anti-hyperkalemic doses (bicarbonate, resonium calcium, fludrocortisone) were noted.

RESULTS

Our study included 29 patients; most were men (aged 45.8 ± 15 years). Body weight did not significantly change after introduction of fludrocortisone (79.53 ± 24.31, 79.82 ± 23.85, 80.62 ± 24.24, 77.03 ± 20.7, and 79.21 ± 27.93 kg at baseline and at postdose week 1, 2, 4, and 8, respectively). Systolic and diastolic blood pressure levels were also similar at baseline versus postdose. Steroid doses (prednisolone) were significantly reduced over 1 month (15.7 ± 12.4, 14.1 ± 10.19, 12.6 ± 8.7, 9.5 ± 5.2, and 9.5 ± 5.2 mg/ day). Serum potassium levels significantly improved (5.18 ± 0.58, 4.9 ± 0.49, 4.8 ± 0.54, 4.8 ± 0.65, and 4.4 ± 0.72 mmol/L). Serum creatinine levels significantly improved by postdose week 8 (129.28 ± 48.9, 130.92 ± 52.2, 127.66 ± 50.9, 121.42 ± 41.7, and 124.1 ± 51.27 μmol/L). Serum bicarbonate levels remained similar.

CONCLUSIONS

Fludrocortisone was a safe and effective option in management of calcineurin inhibitor-induced hyperkalemia among renal transplant recipients.

Fludrocortisone Is an Effective Treatment for Hyperkalaemic Metabolic Acidosis in Kidney Transplant Recipients on Tacrolimus: A Case Series

BACKGROUND

Hyperkalaemia with metabolic acidosis is common but under-reported following kidney transplantation. Calcineurin inhibitors, such as tacrolimus, are widely used in the management of transplant patients and are associated with the development of hyperkalaemia. We report on 10 renal transplant patients, treated with fludrocortisone, following identification of hyperkalaemic metabolic acidosis.

RESULTS

All 10 patients were male aged (mean ± SD) 53.0 ± 13.2 years; 7 were Caucasian and 3 South Asian. Before and after fludrocortisone administration, respective (mean ± SD) serum potassium was 6.1 ± 0.4 mmol/L and 5.3 ± 0.3 mmol/L (p = 0.0002); serum bicarbonate 18.5 ± 1.6 mmol/L and 20.5 ± 2.3 mmol/L (p = 0.002); serum sodium 135 ± 4.6 mmol/L and 137 ± 2.2 mmol/L (p = 0.0728); serum creatinine 181 ± 61 μmol/L and 168 ± 64 μmol/L (p = 0.1318); eGFR 42 ± 18 mL/min and 46 ± 18 mL/min (p = 0.0303); blood tacrolimus 10.1 ± 2.9 ng/mL and 10.4 ± 1.4 ng/mL (p = 0.7975); and blood pressure 129 ± 15/79 ± 25 mm Hg and 126 ± 24/75 ± 7 mm Hg. Pre-fludrocortisone, there were 7 episodes of serum potassium ≥6.5 mEq/L, with 4 patients requiring admission for the treatment of hyperkalaemia. Following fludrocortisone, no patients had hyperkalaemia requiring inpatient management.

CONCLUSIONS

Treatment of hyperkalaemic metabolic acidosis in transplant patients on tacrolimus with low-dose fludrocortisone resulted in rapid correction of hyperkalaemia and acidosis without significant effects on blood pressure or serum sodium. Fludrocortisone can be an effective short-term option for the treatment of hyperkalaemic metabolic acidosis in kidney transplant recipients on tacrolimus; however, patient selection remains important in order to reduce to risk of potential adverse effects.

Management of hyperkalemia: A focus on kidney transplant recipients

Hyperkalemia is a frequent complication among kidney transplant recipients that can lead to fatal arrhythmias. The causes of hyperkalemia post kidney transplant are multifactorial and often are drug-induced, and include decreased glomerular filtration rate, tubular dysfunction, and impaired sodium delivery in the distal nephron. This review will discuss pathophysiology and recent updates in the management of both acute and chronic hyperkalemia with a focus on kidney transplant recipients.

The Many Faces of Calcineurin Inhibitor Toxicity-What the FK?

Calcineurin inhibitors (CNIs) are both the savior and Achilles' heel of kidney transplantation. Although CNIs have significantly reduced rates of acute rejection, their numerous toxicities can plague kidney transplant recipients. By 10 years, virtually all allografts will have evidence of CNI nephrotoxicity. CNIs have been strongly associated with hypertension, dyslipidemia, and new onset of diabetes after transplantation-significantly contributing to cardiovascular risk in the kidney transplant recipient. Multiple electrolyte derangements including hyperkalemia, hypomagnesemia, hypercalciuria, metabolic acidosis, and hyperuricemia may be challenging to manage for the clinician. Finally, CNI-associated tremor, gingival hyperplasia, and defects in hair growth can have a significant impact on the transplant recipient's quality of life. In this review, the authors briefly discuss the pharmacokinetics of CNI and discuss the numerous clinically relevant toxicities of commonly used CNIs, cyclosporine and tacrolimus.

Fludrocortisone-a treatment for tubulopathy post-paediatric renal transplantation: A national paediatric nephrology unit experience

Calcineurin inhibitors post-renal transplantation are recognized to cause tubulopathies in the form of hyponatremia, hyperkalemia, and acidosis. Sodium supplementation may be required, increasing medication burden and potentially resulting in poor compliance. Fludrocortisone has been beneficial in addressing tubulopathies in adult studies, with limited paediatric data available. A retrospective review of data from an electronic renal database from December 2014 to January 2016 was carried out. Forty-seven post-transplant patients were reviewed with 23 (49%) patients on sodium chloride or bicarbonate. Nine patients, aged 8.3 years (range 4.9-16.4), commenced fludrocortisone 22 months (range 1-80) after transplant and were followed up for 9 months (range 2-20). All patients stopped sodium bicarbonate; all had a reduction or no increase in total daily doses of sodium chloride. Potassium levels were significantly lower on fludrocortisone, 5.2 vs 4.5 mmol/L, P = .04. No difference was noted in renal function (eGFR 77.8 vs 81.7 mL/min/1.73 m² , P = .45) and no significant increase in systolic blood pressure (z-scores 0.99 vs 0.85, P = .92). No side effects secondary to treatment with fludrocortisone were reported. A significant proportion of renal transplant patients were on sodium supplementation and fludrocortisone reduced sodium supplementation without significant effects on renal function or blood pressure. Fludrocortisone appears to be safe and effective for tubulopathies in children post-transplantation.

How Dangerous Is Hyperkalemia?

Hyperkalemia is a potentially life-threatening electrolyte disorder appreciated with greater frequency in patients with renal disease, heart failure, and with use of certain medications such as renin angiotensin aldosterone inhibitors. The traditional views that hyperkalemia can be reliably diagnosed by electrocardiogram and that particular levels of hyperkalemia confer cardiotoxic risk have been challenged by several reports of patients with atypic presentations. Epidemiologic data demonstrate strong associations of morbidity and mortality in patients with hyperkalemia but these associations appear disconnected in certain patient populations and in differing clinical presentations. Physiologic adaptation, structural cardiac disease, medication use, and degree of concurrent illness might predispose certain patients presenting with hyperkalemia to a lower or higher threshold for toxicity. These factors are often overlooked; yet data suggest that the clinical context in which hyperkalemia develops is at least as important as the degree of hyperkalemia is in determining patient outcome. This review summarizes the clinical data linking hyperkalemia with poor outcomes and discusses how the efficacy of certain treatments might depend on the clinical presentation.

Tacrolimus-Induced Type IV Renal Tubular Acidosis following Liver Transplantation

Calcineurin inhibitors remain an integral component of immunosuppressive therapy regimens following solid organ transplantation. Although nephrotoxicity associated with these agents is well documented, type IV renal tubular acidosis is a rare and potentially underreported complication following liver transplantation. Hepatologists must be able to recognize this adverse effect as it can lead to fatal hyperkalemia. We describe a case of tacrolimus-induced hyperkalemic type IV renal tubular acidosis in a patient following an orthotopic liver transplant for alcoholic cirrhosis.