Blood pressure lowering and cerebral blood flow: a comparison of the effects of carvedilol and propranolol on the cerebral circulation in hypertensive patients.
The first part of this article concerns the general relation between blood pressure lowering and cerebral blood flow. Factors known to affect cerebral blood flow are reviewed, and recent advances in the field of innervation of cerebral blood vessels are outlined. Special emphasis is placed on the importance of the phenomenon of autoregulation and how this is disturbed in patients with hypertension. Not all antihypertensive drugs exert the same action on the cerebral circulation to produce the same blood pressure-lowering effect. In addition, the actions exerted by common antihypertensive drugs on the cerebral circulation are described. The second part of the article provides a comparison between the effect of carvedilol and that of propranolol on blood pressure reduction and cerebral blood flow. In a double-blind, crossover study involving 14 patients with mild-to-moderate hypertension, carvedilol was shown to have no effect on cerebral blood flow, whereas there was a slight tendency for lower flows to occur with the use of propranolol. Because of the small sample size, statistical significance was not reached. These results are consistent with other recently published findings.
James
I M
IM
Academic Department of Medicine, Royal Free Hospital School of Medicine, London, England.
Yogendran
L
L
McLaughlin
K
K
Munro
C
C
D000293:Adolescent; D000328:Adult; D000368:Aged; D000806:Angiotensin-Converting Enzyme Inhibitors / Q000494:pharmacology; D000959:Antihypertensive Agents / Q000494:pharmacology* / Q000627:therapeutic use; D001794:Blood Pressure / Q000187:drug effects*; D002121:Calcium Channel Blockers / Q000494:pharmacology; D002227:Carbazoles / Q000494:pharmacology* / Q000627:therapeutic use; D000077261:Carvedilol; D002560:Cerebrovascular Circulation / Q000187:drug effects*; D004311:Double-Blind Method; D006339:Heart Rate / Q000187:drug effects; D006801:Humans; D006973:Hypertension / Q000188:drug therapy / Q000503:physiopathology*; D008875:Middle Aged; D011412:Propanolamines / Q000494:pharmacology* / Q000627:therapeutic use; D011433:Propranolol / Q000494:pharmacology* / Q000627:therapeutic use
D000806:Angiotensin-Converting Enzyme Inhibitors; D000959:Antihypertensive Agents; D002121:Calcium Channel Blockers; D002227:Carbazoles; D011412:Propanolamines; D000077261:Carvedilol; D011433:Propranolol