The haemodynamic and hormonal responses after clonidine occur independently of sedation in essential hypertension.
1. To investigate the contribution of sedation to the cardiovascular effects induced by clonidine, we studied patients with essential hypertension on two separate occasions when similar levels of sedation were induced by clonidine and nitrazepam. 2. After clonidine, there was a fall in blood pressure, heart rate, digital skin vascular resistance and plasma noradrenaline which is consistent with its ability to reduce sympathetic outflow. Dissociation of the circulatory/neurohormonal and sedative responses after clonidine indicated that sedation alone is not an important factor in the blood pressure lowering effect of clonidine. 3. The absence of a fall in blood pressure, heart rate, digital skin vascular resistance and plasma noradrenaline after nitrazepam further suggest that sedation did not influence the hypotensive response in essential hypertension.
Kooner
J S
JS
Department of Medicine, St. Mary's Hospital and Medical School, London.
Peart
W S
WS
Mathias
C J
CJ
D000328:Adult; D000450:Aldosterone / Q000097:blood; D003000:Clonidine / Q000009:adverse effects / Q000627:therapeutic use*; D004837:Epinephrine / Q000097:blood; D005260:Female; D006439:Hemodynamics / Q000187:drug effects*; D006728:Hormones / Q000097:blood*; D006801:Humans; D006973:Hypertension / Q000188:drug therapy* / Q000503:physiopathology; D006993:Hypnotics and Sedatives; D008297:Male; D008875:Middle Aged; D009638:Norepinephrine / Q000097:blood; D012083:Renin / Q000097:blood; D012881:Skin Temperature / Q000187:drug effects; D014655:Vascular Resistance / Q000187:drug effects
D006728:Hormones; D006993:Hypnotics and Sedatives; D000450:Aldosterone; D012083:Renin; D003000:Clonidine; D009638:Norepinephrine; D004837:Epinephrine