We tested the hypothesis that clonidine produces a dose-dependent increase in the sweating threshold but does not reduce the gain of sweating. Six healthy male volunteers were evaluated, each on three separate days in random order. In one, saline was administered; in another, a 2-micrograms/kg bolus of clonidine was followed by an infusion at 2 micrograms.kg-1.h-1, and on a third day, a 4-micro...

BACKGROUND Clonidine, a partial presynaptic and postsynaptic alpha-adrenoceptor agonist, has been shown to lower blood pressure in normal subjects but not in tetraplegics; however, the mechanisms of this action have not been elucidated. METHODS AND RESULTS The hemodynamic and hormonal basis of the hypotensive action of clonidine was investigated in tetraplegics with complete cervical spinal c...

In a previous study, we showed that clonidine, an α₂-adrenoceptor agonist, administered prior to hypoxia improves post-hypoxic contractility (PC) and endothelium-dependent dilatation (PED) in isolated young rat aortas. These effects were not investigated in old rats. Ageing influences vascular physiology and modifies the response to vasoactive drugs. Some drugs, such as simvastatin, improve end...

BACKGROUND AND AIMS It has been reported that clonidine when used as an additive in a dose of 90 μg in adults increases the duration of peripheral nerve blocks. Hence, this study was conducted to evaluate the effect of clonidine in brachial plexus blocks and to compare it with tramadol. MATERIAL AND METHODS Ninety patients posted for upper limb orthopedic surgery were divided randomly into th...

Our previous attempts to investigate the long-term hemodynamic interaction between ethanol and clonidine in telemetered spontaneously hypertensive rats (SHRs) were hampered by the lack of a sustained hypotensive response to continuous clonidine exposure. This limitation was circumvented when we adopted a limited-access clonidine (8:30 AM-4:30 PM) paradigm in a recent study. The latter paradigm ...

The ability of hypoosmotic solution, prostaglandin E1 (PGE1) and clonidine to influence intraocular pressure (IOP) by a central mechanism was studied using the technique of ventriculocisternal perfusion in conscious rabbits. IOP remained unchanged during the perfusion of 150 mOsm artificial cerebrospinal fluid. IOP rapidly increased by 15 mmHg during the perfusion of PGE1 at the dose of 1 or 3 ...

BACKGROUND AND OBJECTIVES Clonidine is added to intrathecal local anesthetics to improve intraoperative analgesia and to increase the duration of sensory and motor block. The aim of this systematic review is to quantify beneficial and harmful effects of clonidine when used as an adjuvant to intrathecal local anesthetics for surgery. METHODS We included data from 22 randomized trials (1,445 pa...

BACKGROUND AND OBJECTIVES Clonidine and dexmedetomidine are alpha2-adrenergic agonists with analgesic proprieties which potentiate local anesthetic effects when epidurally administered. The goal of this study was to evaluate the analgesia and sedation promoted by clonidine or dexmedetomidine associated to epidural ropivacaine, in the postoperative period of subcostal cholecystectomy. METHODS ...

BACKGROUND Through their action on the locus coeruleus, alpha2-adrenoceptor agonists induce rapidly reversible sedation while partially preserving cognitive brain functions. Our goal in this observational study was to map brain regions whose activity is modified by clonidine infusion so as to better understand its loci of action, especially in relation to sedation. METHODS Six ASA I-II right-...