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Query: UMLS:C0030193 (pain)
 261,466 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

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

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

Clonidine and glutamate were applied by iontophoresis to cells in the superficial 3 laminae of the spinal cord in the anaesthetised rat. Only cells that were excited by glutamate (up to 150 nA) were studied. Some spontaneously active cells could be excited by clonidine (up to 100 nA). However, when applied to non-spontaneous cells, clonidine had no effect at any dose level. When ejected in a cyclic pattern alternating with glutamate ejection, clonidine powerfully amplified the response of many cells to the glutamate stimulus. This effect was seen only on cells with small-amplitude spikes and low-threshold (LT) receptive fields. The amplification was often sustained and could outlast the clonidine ejection by several minutes. Clonidine had a long-lasting inhibitory effect on the responses to glutamate of cells with high-threshold (HT) or wide-dynamic-range (WDR) receptive fields. Clonidine appeared to selectively decrease the responsiveness of WDR cells to noxious stimulation. It is suggested that an amplification of the response of LT cells to other excitatory inputs could contribute to the analgesic action of clonidine.
Pain 1993 May
PMID:The effects of iontophoretic clonidine on neurones in the rat superficial dorsal horn. 833 84

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

Some clinical as well as pharmacological indications seem to suggest that a reduction of the noradrenergic tone occurs in cluster headache (CH), during both the active and remission periods. But sharp fluctuations of the sympathetic system may trigger the attacks. Clonidine, an alpha-2-adrenergic presynaptic agonist, regulates the sympathetic tone in the central nervous system. Therefore, a continuous administration of low-dose clonidine could be potentially beneficial in the active phase of CH by antagonizing the variations in noradrenergic tone. After a run-in week, we administered transdermal clonidine (5 - 7.5 mg) for one week to 13 patients suffering from CH, either episodic (8 cases) or chronic (5 cases). During clonidine treatment, the mean weekly frequency of attacks dropped from 17.7 +/- 7.0 to 8.7 +/- 6.6 (p = 0.0005), the pain intensity of attacks measured on the visual analogue scale from 98.0 +/- 7.2 to 41.1 +/- 36.1 mm (p = 0.001), and the duration from 59.3 +/- 21.9 to 34.3 +/- 24.6 min (p = 0.02). This open pilot study strongly suggests that transdermal clonidine may be an effective drug in the preventive treatment of CH. Its efficacy is possibly due to its central sympatho-inhibition, which reduces or prevents the occurrence of fluctuations of noradrenaline release that may induce the attacks.
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PMID:Efficacy of transdermal clonidine in short-term treatment of cluster headache: a pilot study. 920 77

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

This is a prospective randomized double-blind trial conducted to determine whether preoperative orally administered clonidine causes or potentiates postoperative vomiting in 140 children (3-12 yr) undergoing strabismus surgery. They were all inpatients and classified randomly into four groups (n = 35 each); placebo (control), diazepam 0.4 mg.kg-1, clonidine 2 micrograms.kg-1, and clonidine 4 micrograms.kg-1. These agents were administered 93-112 min (mean; 100 min) before the anticipated time of induction of anaesthesia. All children received inhalational anaesthesia with halothane and nitrous oxide in oxygen. Muscle relaxation in all patients was obtained with vecuronium and residual neuromuscular blockade was antagonized with neostigmine and atropine before tracheal extubation. Diclofenac suppository was prescribed to prevent postoperative pain. No opioids or postoperative antiemetics were administered. All children remained in hospital for two days postoperatively. The incidence and frequency of vomiting were compared in the groups with Kruskall-Wallis Rank test. Clonidine 4 micrograms.kg-1 caused a lower incidence and frequency of vomiting than did placebo and diazepam (incidence and frequency: 11% and 1.37% and 3, and 34% and 2 in clonidine 4 micrograms.kg-1, placebo, and diazepam, respectively; P < 0.05 for clonidine 4 micrograms.kg-1 vs placebo and diazepam). However, low-dose clonidine was ineffective. These data suggest that preanaesthetic medication with clonidine 4 micrograms.kg-1 may be useful for preventing emesis following strabismus surgery. This property of clonidine indicates that it may be superior to other sedative premedicants such as diazepam and midazolam.
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PMID:Oral clonidine premedication reduces vomiting in children after strabismus surgery. 859 May 7

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

While the potent analgesic properties of clonidine, a centrally-acting antihypertensive agent, in humans is well described, its analgesic effect when administered into the pleural cavity is largely unknown. We have used intrapleural clonidine as a primary analgesic agent for postoperative pain control in two patients who had undergone cholecystectomy. Clonidine was instilled into the pleural space at the end of the operation via a silastic catheter placed through the seventh intercostal space. Oral pain medications were resumed within 48 hours after removal of the intrapleural catheter. In both patients, there was a substantial improvement in pulmonary function correlating with adequate pain control. No complications were noted secondary to the use of intrapleural clonidine. We conclude that intrapleurally administered clonidine is sufficient to provide adequate postoperative analgesia following abdominal surgery.
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PMID:The use of intrapleural clonidine for postoperative pain control. 867 28

Spasticity and pain are common disabling sequelae following spinal cord injury (SCI) and are often difficult to manage. The two problems are also not infrequently related. A variety of pharmacological and other approaches have been described for management of these problems in SCI. This case study reports a 32-year-old woman with an established incomplete C5 tetraplegia (anterior cord syndrome) who developed severe, intractable anal spasm following a hemorrhoidectomy, which persisted despite very good healing. This prevented evacuation of her bowels and resulted in severe rectal pain and episodes of autonomic dysreflexia. Attempts to modify the rate and mode of delivery of intrathecal baclofen through an existing programmable infusion pump failed to reduce anal sphincter spasm or improve symptoms. A right-sided pudendal block with lignocaine provided some relief. Clonidine was added to baclofen in the pump reservoir and both drugs were administered intrathecally in combination. This resulted in an immediate improvement in anal sphincter spasm and pain relief, allowing rapid reestablishment of her normal bowel pattern without need for any supplemental analgesia. It appears that intrathecal clonidine may have an important role in the treatment of spasticity, either as a single or an adjuvant agent, when intrathecal baclofen alone is ineffective or there is increasing tolerance to baclofen. Intrathecal clonidine may also prove useful in the management of intractable neuropathic pain.
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PMID:Intrathecal clonidine and baclofen in the management of spasticity and neuropathic pain following spinal cord injury: a case study. 870 79


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