CJA
HOME HELP FEEDBACK SUBSCRIPTIONS ARCHIVE SEARCH TABLE OF CONTENTS
This Article
Right arrow Full Text (PDF)
Right arrow Submit a scholarly reply
Right arrow Alert me when this article is cited
Right arrow Alert me when eLetters are posted
Right arrow Alert me if a correction is posted
Services
Right arrow Similar articles in this journal
Right arrow Similar articles in PubMed
Right arrow Alert me to new issues of the journal
Right arrow Download to citation manager
Right arrow reprints & permissions
Citing Articles
Right arrow Citing Articles via HighWire
Right arrow Citing Articles via Google Scholar
Google Scholar
Right arrow Articles by Inomata, S.
Right arrow Articles by Akiyoshi, Y.
Right arrow Search for Related Content
PubMed
Right arrow PubMed Citation
Right arrow Articles by Inomata, S.
Right arrow Articles by Akiyoshi, Y.

Canadian Journal of Anesthesia, Vol 42, 119-125, Copyright © 1995 by Canadian Anesthesiologists' Society

ARTICLES

Enhancement of pressor response to intravenous phenylephrine following oral clonidine medication in awake and anaesthetized patients

S Inomata, T Nishikawa, S Kihara and Y Akiyoshi
Department of Anaesthesia, Iwaki Kyoritsu General Hospital, Fukushima, Japan.

Clonidine, an alpha 2-adrenergic agonist, augments the pressor response to intravenous ephedrine. If this effect is partly due to clonidine-induced potentiation of alpha 1-adrenoceptor-mediated vasoconstriction, it is also assumed that clonidine would enhance the pressor effect of phenylephrine as an alpha 1-adrenergic agonist. The authors studied haemodynamic responses to intravenous phenylephrine in 80 patients who received either preanaesthetic medication with clonidine approximately 5 micrograms.kg-1 po (clonidine group, n = 40), or no medication (control group, n = 40). Each group was further divided into either awake subjects (n = 20) or subjects anaesthetized with enflurane and nitrous oxide in oxygen (n = 20). Haemodynamic measurements were made at one-minute intervals for ten minutes after phenylephrine 2 micrograms.kg-1 iv was injected as a bolus. The magnitudes of maximal mean blood pressure increases in the clonidine group (26 +/- 7% (mean +/- SD) for awake and 32 +/- 15% for anaesthetized subjects) were greater (P < 0.05) than in the control group (13 +/- 7% for awake and 18 +/- 7% for anaesthetized subjects). However, there was no difference in the pressor effect of phenylephrine between awake and anaesthetized patients in both groups. Oral clonidine preanaesthetic medication, 5 micrograms.kg-1, augments the pressor responses to phenylephrine 2 micrograms.kg-1 iv in awake and anaesthetized patients. These results suggest that the enhancement of the pressor responses to phenylephrine following oral clonidine may be due to clonidine-induced potentiation of alpha 1-adrenoceptor-mediated vasoconstriction. This implies that restoration of blood pressure can be achieved effectively by phenylephrine in hypotensive patients with clonidine premedication.


This article has been cited by other articles:


Home page
 Anesth. Analg.Home page
Y. Hayakawa-Fujii, H. Iida, and S. Dohi
Propofol Anesthesia Enhances Pressor Response to Ephedrine in Patients Given Clonidine
Anesth. Analg., July 1, 1999; 89(1): 37 - 37.
[Abstract] [Full Text] [PDF]

Home page
 Anesth. Analg.Home page
J. L. Parlow, P. Sagnard, G. Begou, J.-P. Viale, and L. Quintin
The Effects of Clonidine on Sensitivity to Phenylephrine and Nitroprusside in Patients with Essential Hypertension Recovering from Surgery
Anesth. Analg., June 1, 1999; 88(6): 1239 - 1239.
[Abstract] [Full Text] [PDF]


HOME HELP FEEDBACK SUBSCRIPTIONS ARCHIVE SEARCH TABLE OF CONTENTS
Copyright © 1995 by the Canadian Anesthesiologists' Society.