Effects of Losartan on the Renin-Angiotensin-Aldosterone System and Erythrocytosis in Patients with Chronic Obstructive Pulmonary Disease and Systemic Hypertension A. Füsun Ülger, 1 Özlem Özdemir Kumbasar, 1 Özgür Karacan, 1,2 Peri Arbak 1,3 and Doganay Alper 1 1 Department of Chest Diseases, Faculty of Medicine, Ankara University, Ankara, Turkey 2 Department of Chest Diseases, Faculty of Medicine, Baskent University, Ankara, Turkey 3 Department of Chest Diseases, Faculty of Medicine, Abant Izzet Baysal University, Düzce, Turkey Abstract Objective: To evaluate the effects of losartan on blood pressure, erythrocytosis and the renin-angiotensin-aldosterone system (RAS) in patients with erythro- cytosis and hypertensive chronic obstructive pulmonary disease (COPD). Design: Prospective, nonrandomised, two-period study. Patients and Participants: 24 patients were recruited, of whom 20 (17 men) completed the trial. The mean age was 55 ± 8 years (range 40 to 65 years). Erythrocytosis was defined as a persistent elevation of the haematocrit to ≥47% in females and ≥50% in males. Patients were ≤65 years of age and hypertensive according to the WHO criteria. Patients who had hepatic and/or renal dysfunction, acute exacerbation of primary disease, were taking systemic corticosteroids, had any other systemic disease, or showed intolerance during the washout period were excluded. Methods: An initial 2-month period on a standard regimen with nasal oxygen (2 L/min, 18 h/day) and bronchodilators (inhaled salbutamol, oral theophylline, inhaled ipratropium bromide) was followed by a second 2-month period during which losartan was administered as an antihypertensive agent in addition to standard therapy. Routine biochemical and haematological monitoring was carried out. Systolic and diastolic blood pressures (SBP and DBP, respectively) were measured. ECG and arterial blood gas analyses were also performed for all patients at the beginning of the study, and all of these clinical and laboratory investigations were performed at 15-day intervals during the study. Plasma renin activity and serum aldosterone and erythropoietin levels were measured both at the beginning and at the end of each 2-month period. Results: No statistically significant changes were found in the measured para- meters at the end of the 2-month standard treatment period. Fatigue and dizziness were reported by four of the patients during the first week of losartan treatment. CLINICAL PHARMACODYNAMICS Clin Drug Invest 2001; 21 (5): 337-343 1173-2563/01/0005-0337/$22.00/0 © Adis International Limited. All rights reserved.