Htg. Bergendahl et al., LOW-DOSE INTRAVENOUS CLONIDINE IN CHILDREN - PLASMA-CONCENTRATIONS AND HEMODYNAMIC-RESPONSE, Acta anaesthesiologica Scandinavica, 41(3), 1997, pp. 381-384
The beneficial perioperative effects of the alpha-2 agonist clonidine
have recently been verified in paediatric patients, and the pharmacoki
netics have been found to be similar to what has been reported in adul
ts. In a previous study we found that 2.5 mu g/kg of clonidine causes
a significant reduction in blood pressure. The aim of the present stud
y was to evaluate if even lower doses of clonidine are associated with
dose dependent or plasma-dependent haemodynamic changes. In a prospec
tive, single, blind, controlled clinical trial, 24 paediatric patients
(age range: 13-78 months) were randomised into three groups: control,
intravenous clonidine 0.625 mu g/kg and intravenous clonidine 1.25 mu
g/kg respectively. Non-invasive blood pressure and heart rate were re
corded at 3-min intervals for 30 min. Plasma concentrations of clonidi
ne were analysed at 15 and 30 min post-injection. A decrease in MABP c
ompared to baseline values was observed in all groups. A significantly
greater reduction in blood pressure was seen in all groups receiving
clonidine compared to control. In conclusion, low doses of clonidine (
0.625 and 1.25 mu g/kg) were found capable of causing a blood pressure
reduction compared to control. We could not establish a plasma concen
tration dependent blood pressure effect. The observed blood pressure r
eductions caused by clonidine were of moderate magnitude. No effect on
heart rate was observed, a finding which most likely is explained by
the inclusion of atropine in the premedication.