Document Detail

Effects of clonidine premedication on the pressor response to alpha-adrenergic agonists.
MedLine Citation:
PMID:  7577287     Owner:  NLM     Status:  MEDLINE    
It has been suggested that postjunctional alpha 1-adrenoceptor mediated vasoconstriction is enhanced by clonidine. We have examined in humans if the pressor responses to noradrenaline and phenylephrine are enhanced by clonidine premedication. Seventy-seven patients were allocated randomly to either clonidine (n = 38) or control (n = 39) groups. Patients in the clonidine group received approximately 5 micrograms kg-1 with famotidine 20 mg, while the control group received famotidine 20 mg alone orally, 90 min before induction of general anaesthesia with thiamylal. In all patients the lungs were ventilated mechanically via tracheal tubes and anaesthesia maintained with 1% end-tidal enflurane and 67% nitrous oxide in oxygen. When a stable haemodynamic state was obtained, either noradrenaline 0.5 microgram kg-1 (n = 40) or phenylephrine 2 micrograms kg-1 (n = 37) was administered randomly i.v. as a bolus, while arterial pressure and heart rate were measured noninvasively at 1-min intervals for 10 min. Although noradrenaline caused significantly greater increases in mean arterial pressure (MAP) in the clonidine group (from 2 to 4 min after i.v. injection) compared with the control group, there were no significant differences in the mean maximal increment in MAP or area under the MAP curve between the two groups. However, i.v. phenylephrine produced a significantly greater increase in MAP from 2 to 7 min (P < 0.05), and greater mean maximal increase in MAP from the baseline value (21 (9) vs 14 (7) mm Hg; P < 0.05) in the clonidine than in the control group.(ABSTRACT TRUNCATED AT 250 WORDS)
M Tanaka; T Nishikawa
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Publication Detail:
Type:  Clinical Trial; Journal Article; Randomized Controlled Trial    
Journal Detail:
Title:  British journal of anaesthesia     Volume:  75     ISSN:  0007-0912     ISO Abbreviation:  Br J Anaesth     Publication Date:  1995 Nov 
Date Detail:
Created Date:  1995-12-28     Completed Date:  1995-12-28     Revised Date:  2004-11-17    
Medline Journal Info:
Nlm Unique ID:  0372541     Medline TA:  Br J Anaesth     Country:  ENGLAND    
Other Details:
Languages:  eng     Pagination:  593-7     Citation Subset:  IM    
Department of Anaesthesia/Critical Care Medicine, Tsuchiura Kyodo General Hospital, Ibaraki-ken, Japan.
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MeSH Terms
Adrenergic alpha-Agonists / pharmacology*
Blood Pressure / drug effects
Clonidine / pharmacology*
Drug Synergism
Heart Rate / drug effects
Middle Aged
Norepinephrine / pharmacology*
Phenylephrine / pharmacology*
Reg. No./Substance:
0/Adrenergic alpha-Agonists; 4205-90-7/Clonidine; 51-41-2/Norepinephrine; 59-42-7/Phenylephrine

From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine

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