Changes in blood count induced by doxazosin treatment in subjects with pheochromocytoma

Objective: Not only pre-treatment with with alfa-receptor antagonists and high-sodium diet, but also intravenous fluid administration immediately before surgery are recommended to minimalize per- and postoperative complications in subjects with pheochromocytoma or paraganglioma (PPGL). Aim of this study was to search for changes in blood count induced by doxazosin. Design and method: We studied PPGL subjects treated with doxazosin before operation and approximately one year after tumor removal. We measured count of blood elements – leukocytes, erythrocytes, thrombocytes, and hemoglobin level before initiation of treatment with doxazosin, during the treatment, and after tumor removal. Diagnosis of PPGL was based on elevated levels of plasma metanephrines preoperatively and was confirmed by histopathology. Results: In this retrospective study, we included 40 subjects with PPGL (15 males and 25 females, 51.8±14 years). Average doxazosin dose was 3.4±1.6 mg and median of duration of doxazosin treatment was 41 (25; 55) days. Leukocyte count decreased from 8.5±2.8 G/L to 7±2 G/L (P<0.001) after doxazosin treatment and to 6.5±1.6 G/L/l (P<0.001 vs. preoperatively) after surgery. Erythrocyte count decreased from 4.7±0.5 T/L to 4.3±0.5 T/L after doxazosin treatment (P = 0.01) and returned back after surgery: 4.6±0.3 T/L (P = 0.04 vs. after doxazosin). Similar results were found for hemoglobin levels: decrease from 140±15 g/L to 130±16 g/L (P<0.001) after doxazosin and increase after surgery to 140±14 g/L (P<0.001 vs. after doxazosin), and for hematocrit values: decrease from 0.42±0.04 to 0.39±0.04 (P<0.001) after doxazosin and increase after surgery to 0.41±0.05 (P<0.001). Platelets decreased significantly from 296±75 G/L to 263±78 G/L (P<0.001) after doxazosin and to 239±63 G/L after tumor removal (P = 0.02 vs. after doxazosin). Conclusions: These data show that doxazosin pretreatment before surgery was accompanied with a significant decrease in red blood cell count, and hemoglobin level and hematocrit compared to values before initiation of doxazosin treatment and after surgery (the highest decrease of hemoglobin value after doxazosin was almost 30 g/l). We conclude that routine fluid administration before PPGL surgery is not supported by presented data.