Alcohol ingestion lowers supine blood pressure, causes splanchnic vasodilatation and worsens postural hypotension in primary autonomic failure.
Patients with pure autonomic failure (PAF) and multiple system atrophy (MSA) may complain of feeling light-headed after alcohol ingestion particularly on assumption of the upright posture. The reasons for this have not been investigated. We therefore studied the effects of oral alcohol (40% vodka in sugar-free orange juice) and placebo (juice only) on the systemic and regional (including superior mesenteric artery, SMA) blood flow in nine patients with PAF and six patients with MSA. After alcohol, there was a fall in supine blood pressure (BP) and vasodilatation in the SMA but no change in cardiac output, or forearm muscle and cutaneous blood flow in either PAF or MSA; BP fell further during head-up tilt with no changes in levels of plasma catecholamines. After placebo, there were no changes while supine. We conclude that alcohol lowers supine BP and dilates the SMA with no change in muscle or cutaneous blood flow. Alcohol also enhances the fall in BP during head-up tilt. This may explain the symptoms experienced by PAF and MSA patients after alcohol.
Chaudhuri
K R
KR
University Department of Clinical Neurology, Institute of Neurology, London, UK.
Maule
S
S
Thomaides
T
T
Pavitt
D
D
Mathias
C J
CJ
D000328:Adult; D000368:Aged; D001342:Autonomic Nervous System Diseases / Q000097:blood / Q000150:complications / Q000503:physiopathology*; D001786:Blood Glucose / Q000032:analysis; D001794:Blood Pressure / Q000187:drug effects; D004837:Epinephrine / Q000097:blood; D000431:Ethanol / Q000009:adverse effects* / Q000097:blood; D005260:Female; D005542:Forearm / Q000098:blood supply; D006339:Heart Rate / Q000187:drug effects; D006439:Hemodynamics / Q000187:drug effects*; D006801:Humans; D007022:Hypotension / Q000139:chemically induced* / Q000209:etiology; D007024:Hypotension, Orthostatic / Q000139:chemically induced / Q000209:etiology; D007328:Insulin / Q000097:blood; D008297:Male; D017538:Mesenteric Artery, Superior / Q000187:drug effects*; D008875:Middle Aged; D009638:Norepinephrine / Q000097:blood; D012039:Regional Blood Flow / Q000187:drug effects; D013933:Thumb / Q000098:blood supply; D014664:Vasodilation / Q000187:drug effects*
D001786:Blood Glucose; D007328:Insulin; D000431:Ethanol; D009638:Norepinephrine; D004837:Epinephrine