title: The effect of spironolactone on the cardiocirculatory responses to upright tilt at sea level and at simulated high altitude.
abstract: The objective of this study was to determine if spironolactone (S) alters the cardiocirculatory responses to upright tilt at sea level (SL;50 m) and during 44 h of simulated altitude (HA;4,600 m). In a double-blind, crossover-designed study, 9 male subjects (age range: 18-25 years) received 25 mg orally, four times per day of either S or an identically-appearing placebo (P) 2 d prior to and during HA. The crossover was separated by 2 weeks. Heart rate, stroke volume, cardiac output, calf blood flow, total peripheral resistance and systemic blood pressure were obtained during supine rest and after 10 min of 60 degrees head-up tilt using an impedance monitor and an electro-sphygmomanometer. The 24-h determinations of urinary volume, sodium and potassium as well as venous plasma values for sodium, potassium and chloride were obtained daily. There were no statistically significant differences between P and S treatment periods for: caloric, electrolytes or fluid ingestion; urinary volume or electrolytes; plasma electrolytes; or any of the cardiocirculatory parameters measured in the supine or upright position at SL or during HA. It was concluded that S did not induce a significant diuresis or significantly alter vascular responsiveness to negatively effect the normal cardiocirculatory responses to upright tilt at sea level or simulated high altitude.
mesh_terms: D000328:Adult; D000531:Altitude; D001274:Atmospheric Pressure; D001794:Blood Pressure / Q000187:drug effects; D002319:Cardiovascular System / Q000187:drug effects*; D004311:Double-Blind Method; D006339:Heart Rate / Q000187:drug effects; D006400:Hematocrit; D006801:Humans; D008297:Male; D011187:Posture; D012039:Regional Blood Flow / Q000187:drug effects; D013148:Spironolactone / Q000494:pharmacology*; D014556:Urine / Q000032:analysis; D014655:Vascular Resistance / Q000187:drug effects
chemical_list: D013148:Spironolactone