Abstract: FR-PO0902
Posaconazole-Induced Hypokalemia
Session Information
- Fluid, Electrolyte, and Acid-Base Disorders: Case Reports - 1
October 23, 2026 | Location: Exhibit Hall A, Convention Center
Abstract Time: 10:00 AM - 12:00 PM
Category: Fluid, Electrolytes, and Acid-Base Disorders
- 1102 Fluid, Electrolyte, and Acid-Base Disorders: Clinical
Authors
- Ragasa, Richard Raymund Reyes, University of California San Diego, La Jolla, California, United States
- Beben, Tomasz, University of California San Diego, La Jolla, California, United States
Introduction
This uncommon case of hypokalemia illustrates the importance of integrating multiple lab and clinical findings with a medication review to diagnose a reversible etiology.
Case Description
A 64 year old female with acute myeloid leukemia on cytarabine was admitted for severe hypokalemia while taking posaconazole 300 mg daily for 17 days. She denied diuretic usage and had no nausea, vomiting, or diarrhea. Her systolic blood pressure was 150 mmHg (baseline 110s-120s) and she was euvolemic.
Initial blood work showed K 2 mmol/L, bicarbonate 32 mmol/L, Cr 0.34 mg/dL, and glucose 108 mg/dL. Urine studies after initial K repletion to 2.8 mmol/L showed K 78 mmol/L, osmolality 543 mOsm/kg, and Cr 34 mg/dL. A very high urine K/Cr ratio of 229 mmol K/g Cr supported renal K wasting. Venous blood gas confirmed primary metabolic alkalosis: pH 7.48 with pCO2 49 mmHg and bicarbonate 33 mmol/L. Both renin and aldosterone were suppressed below the lower limits of our assays.
Her prior neutropenia had resolved and posaconazole was stopped on admission. After a total of 350 mmol of KCl supplementation, K stabilized at 3.7-3.8 mmol/L on day 4 and she was discharged on KCl 20 mmol PO daily with outpatient monitoring. Bicarbonate normalized and blood pressure returned to baseline.
Isavuconazonium was utilized for further neutropenic prophylaxis. Neither hypokalemia, metabolic alkalosis, nor elevated blood pressure have recurred in the subsequent four months of follow-up.
Discussion
Patients with malignancy on chemotherapy can have multiple causes of hypokalemia and acid-base disturbances including nausea, vomiting, diarrhea, and poor oral intake. In our case, there was severe hypokalemia despite elevated blood pressure and no significant gastrointestinal symptoms, prompting a further search for a cause.
Similar to black licorice, pozaconazole inhibits 11-beta-hydroxysteroid dehydrogenase type 2. This decreases cortisol’s converstion to cortisone at target tissues, leading cortisol to act as the major circulating mineralocorticoid. This accounts for suppressed renin and aldosterone levels, hypokalemia from renal K wasting, metabolic alkalosis, and elevated blood pressure. As demonstrated, switching to a different antifungal can fully reverse this. However, as pozaconazole’s half life is 15-35 hours and these patient often have a large K deficits, it may take several days for labs to normalize, necessitating close monitoring and agressive initial electrolyte repletion.