Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UMLS:C0344307 (analgesia)
 28,200 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

In obstetric patients treated with epidural analgesia during labor and delivery, shivering is quite frequent due to stress, vasodilatation, infusion of fluids, low ambient temperature, and the direct effect of solution injected into the epidural space. Sixty obstetric patients who developed shivering after receiving epidural analgesia for delivery were randomly assigned to treatment with clonidine 0.150 mg i.v. (N = 20), meperidine 50 mg i.v. (N = 20), or saline solution (N = 20). Drug administration was double blind. The effect on shivering (graded as all or none), drowsiness, heart rate, and systolic arterial pressure was evaluated 5 min after the study drug was administered. Clonidine was as effective as meperidine in controlling shivering and caused a greater reduction in heart rate. Drowsiness occurred after clonidine as well as meperidine. Thus, clonidine proved to be effective in controlling shivering and adrenergic response after delivery using epidural analgesia and produced an acceptable level of drowsiness.
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PMID:Effect of clonidine on postpartum shivering after epidural analgesia: a randomized, controlled, double-blind study. 796 79

Phantom limb pain may appear in up to 85% of patients after amputation. There is no effective treatment. Perioperative epidural infusion of morphine and bupivacaine, alone or in combination, is effective in preventing phantom limb pain in patients with pre-existing limb pain. Serious side-effects, however, make them difficult to manage on a general ward. Clonidine has been shown to be an effective postoperative analgesia when applied epidurally. To mitigate the potentially serious side-effects of all these drugs, we have studied their combined efficiency in preventing phantom limb pain in a prospective controlled study of 24 patients undergoing lower limb amputation. In the study group (n = 13), an epidural infusion containing bupivacaine 75 mg, clonidine 150 micrograms and diamorphine 5 mg in 60 ml normal saline was given at 1-4 ml/h 24-48 h preoperatively and maintained for at least 3 days postoperatively. The control group (n = 11) received on-demand opioid analgesia. Pain was assessed by visual analogue scale at 7 days, 6 months and 1 year. At 1 year follow-up, one patient in the study group and eight patients in the control group had phantom pain (P < 0.002) and two patients in the study group versus eight patients in the control group had phantom limb sensation (P < 0.05). There was no significant improvement in stump pain. We conclude that perioperative epidural infusion of diamorphine, clonidine and bupivacaine is safe and effective in reducing the incidence of phantom pain after amputation.
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PMID:Prevention of phantom pain after major lower limb amputation by epidural infusion of diamorphine, clonidine and bupivacaine. 771 55

The neurotransmitters adrenaline and noradrenaline are non-selective adrenergic agonists which interact with both subtypes of alpha- and beta-receptors. Clonidine, an alpha 2-adrenergic drug with a selectivity ratio of 200/1 for alpha 2/alpha 1 has been used in clinical practice for more than 20 years. Although alpha 2-agonists have vasoconstrictor properties, sympatholytic effects on the central nervous system predominate. As a result, the sympathetic outflow from the medullary pressor centres is decreased mediating the hypotensive effects of the alpha 2-agonists. These compounds also exhibit sedative, anxiolytic, analgesic, and haemodynamic stabilising properties. The identification of alpha 2-adrenoceptors has yielded information on their biochemical properties, signal transduction, modulation of the sympathetic nervous system and neurotransmission. The classification of alpha 2-receptors based on anatomical locations and identified as presynaptic alpha 2-receptors and postsynaptic alpha 1-receptors proved to be untenable after postsynaptic and extrasynaptic alpha 2-receptor locations had been identified. At least 3 isoreceptors which are heterologously distributed in the brain have been identified. Guanine nucleotide proteins (G proteins) couple the receptor to an effector mechanism (i.e. intracellular messenger cascade, ion channel). More selective for the alpha 2-adrenoceptor than clonidine is dexmedetomidine (1600/1 of alpha 2/alpha 1), a very potent agonist at the alpha 2-adrenoceptor. Imidazole derivatives (like clonidine and dexmedetomidine) also bind to other nonadrenergic receptors ("imidazoline receptors") which may produce some effects (i.e. vagotonia) previously ascribed to alpha 2-adrenoceptors. alpha 2-receptors exist in brain tissue and several peripheral organs and tissues including the liver, eye, kidney, pancreas and platelets. Anaesthetic interest has focussed on reductions in anaesthetic requirements since experimental and clinical studies have shown that alpha 2-agonists expert powerful analgesic and anaesthetic effects. The hypnotic response is probably mediated by activation of alpha 2-adrenoceptors in the locus coeruleus. Analgesia is induced by modulation of the nociceptive pathway at the level of the dorsal root neuron and other sites not yet unambiguously characterised. Dexmedetomidine reduces the anaesthetic requirements for halothane by more than 90%. Cerebral blood flow and intraocular pressure are reduced by alpha 2-agonists. Epidural, intrathecal, intravenous and transdermal application of clonidine resulted in pain reduction, during and following surgery and in patients with neurogenic or otherwise intractable cancer pain. Administration of alpha 2-agonists induces only minor respiratory effects. Salivary flow is reduced by alpha 2-agonists and gastric and small-bowel motility is decreased.(ABSTRACT TRUNCATED AT 400 WORDS)
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PMID:[Alpha 2-agonists in anesthesia and intensive medicine]. 809 70

Intraspinal administration of alpha 2 adrenergic agonists produces analgesia, but clinical application of these agents is limited by dose-dependent sedation and hypotension. Recently, neostigmine has been demonstrated to counteract hypotension in sheep and enhance antinociception to tail flick in rats from spinally administered alpha 2 adrenergic agonists. We investigated this spinal interaction further in chronically prepared, conscious sheep, testing antinociception with a mechanical pressure stimulus on the forelimb. Clonidine produced dose-dependent antinociception which was antagonized by idazoxan and enhanced by neostigmine, although it was unaltered by methylatropine. Clonidine increased acetylcholine in cerebrospinal fluid, an effect potentiated by physostigmine and blocked by idazoxan. The highly lipid-soluble alpha 2 adrenergic agonists dexmedetomidine and clonidine produced antinociception, whereas the poorly lipid-soluble ST-91 (2,[2,6-diethylphenylamino]-2-imidazoline) produced antinociception only at much larger doses and did not affect cerebrospinal fluid levels of acetylcholine. In human volunteers, epidurally administered clonidine increased cerebrospinal fluid acetylcholine levels at the time of peak analgesia. These results support the existence of an interaction between alpha 2 adrenergic and cholinergic mechanisms of analgesia at the spinal level and underscore the importance of lipid solubility in the actions of spinally administered drugs in sheep.
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PMID:A cholinergic interaction in alpha 2 adrenoceptor-mediated antinociception in sheep. 809 58

The aim of the present study was to investigate whether clonidine and morphine interact positively to produce analgesia against the low intensity tonic pain represented by the formalin model in rats. Sub-threshold doses of morphine (0.5 mg kg-1) and clonidine (0.025 mg kg-1) were found to elicit marked antinociceptive effects when co-administered intraperitoneally, 15 min prior to formalin challenge. Repeated administration of this combination for eight days did not exhibit any significant decay of this analgesic response, whilst morphine (2 mg kg-1)-induced analgesia, deteriorated after similar administration. Clonidine and morphine thus exhibit a supra-additive effect against low intensity pain with negligible potential for induction of tolerance. This finding may be relevant for the long term control of chronic pain in certain clinical conditions.
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PMID:Morphine, clonidine coadministration in subanalgesic doses: effective control of tonic pain. 819 45

Clonidine produces analgesia via a non-opioid mechanism and it may be used as an interesting adjuvant to local anaesthetics and opioids in obstetric analgesia. To examine the effects of the addition of clonidine to bolus injections of bupivacaine, adrenaline and sufentanil, we enrolled 50 women receiving extradural analgesia for vaginal delivery into a double-blind study. They were allocated randomly to two groups: group A received a 10-ml extradural solution of bupivacaine 12.5 mg combined with adrenaline 25 micrograms and sufentanil 10 micrograms; group B received the same solution with clonidine 30 micrograms. Each patient was allowed two subsequent injections of the chosen solution. Subsequently, if still in the first stage of labour, analgesia was augmented with additional 10-ml injections of bupivacaine 12.5 mg with adrenaline 25 micrograms, without sufentanil or clonidine. The latter solution was used for perineal analgesia in group A; clonidine 30 micrograms was added in group B. During the first and second stages of labour, there was no difference between the two groups in duration of analgesia after the first injection (142 min in group A; 127 min in group B), number of injections (1.8 in group A; 1.9 in group B) and the total bupivacaine requirements (33.9 mg in group A; 34 mg in group B). The quality of analgesia was evaluated as very good in both groups (23/25 in group A; 24/25 in group B). The degree of motor block or the frequency of other side effects were not enhanced by clonidine.(ABSTRACT TRUNCATED AT 250 WORDS)
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PMID:Clonidine combined with sufentanil and bupivacaine with adrenaline for obstetric analgesia. 825 Dec 74

We studied 10 patients with chronic back pain who had claimed benefit with a previous extradural dose of clonidine 150 micrograms combined with local anaesthetic. We compared a single dose of clonidine 150 micrograms given by either the extradural or i.v. route in a double-blind, randomized, double-dummy and cross-over fashion, with 80% power to detect a difference in the analgesic effect of the two routes. Pain intensity, pain relief, adverse effects, mood, sedation and vital signs were assessed by a nurse observer. I.v. clonidine produced significantly (P < 0.04) greater analgesia than extradural clonidine in one of the five analgesic outcome measures. Clonidine given by either route produced statistically significant sedation and significant decreases in arterial pressure and heart rate. In this study, extradural clonidine had no significant clinical advantages compared with i.v. clonidine; clonidine 150 micrograms by either route produced a high incidence of adverse effects.
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PMID:Single-dose, randomized, double-blind, double-dummy cross-over comparison of extradural and i.v. clonidine in chronic pain. 825 Dec 76

For decades the adrenergic alpha2 agonist clonidine has been considered to be one of the classical, centrally acting antihypertensive agents. In addition to its antihypertensive and sympathicolytic effects, in recent studies clonidine has been demonstrated to be an effective sedative and analgesic and to reduce the amount of anaesthetic agents required. Therefore, a reconsideration of possible new indications for clonidine in clinical anaesthesiology seems to be justified. This paper presents the pharmacological basis for treatment with clonidine and reviews the extensive literature on its clinical indications in anaesthesia. Clonidine apparently produces its sedative and anaesthetic-sparing effects by stimulation of centrally located alpha2 adrenoceptors. Analgesia seems to be mediated mainly by activation of alpha2 adrenoceptors in the dorsal horn of the spinal cord. Considering its clinical indications, clonidine is often used as a supplement in the treatment of alcohol withdrawal syndromes. Future indications for clonidine may be the treatment of postoperative shivering and chronic pain management. Administration of clonidine in combination with a local anaesthetic prolongs analgesia and motor blockade. Its use in premedication and postoperative pain management may be limited by its principal effects of hypotension and bradycardia. In future, cardiovascular side effects may be minimized if all the subtypes of alpha2 adrenoceptors, their distribution within the central nervous system, and their specific action are clearly defined. This could result in a detailed therapeutic index of more selective and potent alpha2 agonists.
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PMID:[The role of clonidine in anesthesia]. 848 Aug 99

Clonidine is an effective preanesthetic medication in children, providing a preoperative sedative effect. The analgesic properties of the drug have been well documented in adults. The current study was designed to investigate the effect of oral clonidine given preoperatively on postoperative pain in children undergoing minor surgery. In a prospective, randomized, controlled clinical trial, 90 children aged 5-12 yr undergoing elective ophthalmic, urologic, and otologic surgery received placebo (control), clonidine 2 micrograms/kg, or clonidine 4 micrograms/kg. These drugs were administered 105 min before the estimated time of induction of anesthesia and followed by treatment with oral atropine 0.03 mg/kg 60 min before anesthesia. Anesthesia was induced and maintained with halothane and nitrous oxide in oxygen. Postoperative pain was assessed by a blinded observer using an objective pain scale (OPS). Clonidine 4 micrograms/kg provided lower OPS (highest) scores during 12 h after surgery and reduced requirement for postoperative supplementary analgesic (diclofenac suppository) compared with the other two regimens. These data suggest that oral clonidine premedication (4 micrograms/kg) is a possible approach to facilitating postoperative analgesia in children undergoing minor surgery.
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PMID:Oral clonidine premedication reduces postoperative pain in children. 1203 63

Postoperative analgesia inhibits the stress cascade with negative effects on whole organism. Therefore the spectrum of drugs used for soothing postoperative pain quickly widens. The epidural route appears as being logical, since due to the direct effect in the transmission and processing of pain it suffices with a lower dosage. The authors refer to a group of 30 patients postoperatively treated by a combination of tramadol and Clonidine administrated by means of an epidural catheter. 26 patients evaluated the induced analgesia as excellent or sufficient. (Tab. 3, Ref. 4).
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PMID:[Postoperative analgesia with epidural administration of a combination of tramadol and clonidine]. 862 52


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