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

The phencyclidine derivative, ketamine hydrochloride, combines cardiovascular stimulating effects with antiarrhythmic properties and, therefore, the drug has been shown to be a highly suitable anesthetic for coronary artery surgery. This intravenously and intramuscularly administered "dissociative" anesthetic selectively depresses pathways and regions of the central nervous system associated with pain conduction and perception, thereby avoiding undesirable total nervous system depression. 129 patients suffering from marked coronary artery insufficiency underwent aortocoronary by-pass surgery, ketamine being the main anesthetic agent. Ketamine-induced anesthesia proved to be a simple and safe method of pain control during coronary artery reconstructive surgery and, compared with halothane anesthesia, showed a marked reduction of postoperative mortality (5%).
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PMID:[Use of ketamine in cardiac surgery. A preliminary report]. 80 35

Our experience has shown ketamine to be a safe and effective method of providing pain relief during specific procedures in burned children. It renders high doses of narcotics unnecessary and offers children the benefit of general anesthesia without the requirement of endotracheal intubation and a trip to the operating room. The response of parents and staff to the use of ketamine has been positive. Parents often experience feelings of guilt following injury to a child and are eager to employ methods that reduce their child's pain. So far, no parent has refused the administration of ketamine; some have even asked that it be used during subsequent procedures on their child. With adequate pre-procedure teaching, parents are prepared for the possible occurrence of emergent reactions and can assist in reorienting the child during recovery. Staff have found that the stress of doing painful procedures on children is reduced when ketamine is used. The procedures tend to be quicker and the predicament of working on a screaming, agitated child is eliminated. At the same time, nursing staff have had to get used to the nystagmic gaze of the children and accept that these patients are truly anesthetized even though they might move and talk. Despite the success we and others have had with ketamine, several questions about its use in burn patients remain unanswered. The literature does not answer such questions as: Which nursing measures reduce the incidence of emergent reactions? How many ketamine anesthetics can safely be administered to one individual? How does the frequency of administration relate to tolerance in a burn patient? Are there detrimental effects of frequent or long-term use? Clearly, an understanding of these questions is necessary to determine the safe boundaries of ketamine use in burn patients. Ketamine is not a panacea for the problem of pain in burned children. But it is one means of managing procedural pain, which is, after all, a significant clinical factor in treatment and recovery.
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PMID:Ketamine. A solution to procedural pain in burned children. 145 Oct 87

The effects of s.c. doses of naloxone, methysergide and phentolamine on ketamine-induced spinal analgesia were assessed to determine the involvement of opiate, serotonergic and noradrenergic components mediating ketamine's antinociceptive action. Ketamine administered intrathecally (i.t.) produced a significant elevation in tail-flick latency in rats. The spinal antinociceptive effects of ketamine were dose dependently reversed by methysergide (ID50 = 0.008 mg/kg s.c.), phentolamine (ID50 = 0.88 mg/kg s.c.) and naloxone (ID50 = 3.0 mg/kg s.c.). Unlike morphine, which remains analgesic and dependent on opiate interactions following bilateral lesions of the dorsolateral funiculus (DLF), ketamine analgesia was absent following DLF lesions. Thus, ketamine appears to produce an antinociceptive response which is dependent upon the neuronal activity of the descending pain-inhibitory pathways. The monoaminergic components comprising the descending pathways appear to be more prominent in the action of ketamine than they are in the spinal action of morphine. Furthermore, the spinal opioid receptors involved in ketamine's effect may be different from the mu subtype preferred by morphine.
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PMID:The local monoaminergic dependency of spinal ketamine. 164 67

Rectal administration of drugs has become a standard procedure in clinical anesthesia, most notably for anorectal induction in children. Limitations of this method include low bioavailability, a wide scatter of pharmacokinetic and pharmacological results, and poor predictability of the clinical effect in any particular patient. Historically, the rectal route has been used for the administration of smoke ("fumigation") for resuscitation and various other purposes. An ether boiler for rectal application was developed by Pirogoff as early as 1847. The pharmacokinetics of rectally administered drugs are determined by the anatomical properties of the rectum and, owing to interindividual variance, this adds to the inconsistency of absorption. Aspects that can be better controlled include the drug preparation and the vehicle, with hydrophilic solutions resulting in improved absorption. Larger volumes such as are associated with lower concentrations increase the bioavailability by enlarging the mucosal surface in contact with the drug. In contrast to the hypothetical assumption that hepatic circulation may be circumvented--thus avoiding first-pass metabolism--by direct venous drainage from the rectum into the systemic circulation via the vena cava, it has been shown that hepatic clearance is the main factor affecting bioavailability. This may be due to blood flow through anastomoses interconnecting the superior, medium and inferior rectal venous systems. Resorption from the rectum is also determined by physicochemical properties of drugs. According to the pH-partition hypothesis, only the non-ionized moiety of a compound will be available for transmucosal diffusion. The degree of ionization is a function of the local (or microclimate) milieu pH and pKa of the drug; the former is close to neutral in adults but alkaline in most children. Adsorption of feces, intraluminal degradation by microorganisms, metabolism within the mucosal cell, and lymphatic drainage do not significantly affect the fate of rectally administered drugs. In clinical practice, the rectal administration of methohexital and midazolam is an established method of premedication or induction of anesthesia in children; so far, midazolam appears to be associated with fewer complications. Ketamine has been shown to be as effective and as quick-acting as methohexital, but at least in one study its use as sole induction agent was associated with respiratory distress in some cases. However, painful diagnostic or therapeutic procedures in children may be indications for the rectal administration of ketamine. Early trials with rectally administered etomidate have been abandoned since its implication in suppression of cortisol synthesis. Narcotic analgesics in a hydrogel vehicle are effective in adult pain management.(ABSTRACT TRUNCATED AT 400 WORDS)
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PMID:[Rectal administration of drugs. Fundamentals and applications in anesthesia]. 167 54

Both chiral forms of ketamine caused analgesia when administered in subanesthetic doses to human volunteers suffering acute, experimentally induced ischemic pain. S-Ketamine was 4 times more potent than R-ketamine as an analgesic agent in this model system. The relative order of analgesic potency of the two enantiomers was compared to their relative affinity for phencyclidine (PCP) binding sites (associated with the NMDA receptor-operated ion channel) and for sigma binding sites (which are not associated with the NMDA receptor complex). The relative analgesic potency of the enantiomers correlated positively with their relative affinity for PCP sites and negatively with their relative affinity for sigma sites. The results strongly indicate that PCP sites, but not sigma sites, are functional receptors mediating the analgesic effect of ketamine. This is consistent with the hypothesis that NMDA receptors are essential for pain perception in humans. Disturbances of other sensory modalities, in particular somatosensory perception, vision and hearing, were the main side-effects observed. These effects were qualitatively similar for both enantiomers and were closely associated with their analgesic action. The NMDA type of excitatory amino acid receptor thus appears to be widely involved in the processing of sensory afferent signals in the human brain.
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PMID:Evidence of a role for NMDA receptors in pain perception. 196 98

Propofol (Diprivan), a modern intravenous hypnotic, produces a reduction in both cardiac index (CI) and mean arterial pressure (MAP). Ketamine (Ketanest), a potent analgesic, in contrast, causes an increase in MAP and CI. The aim of the present study was to investigate whether the combination of propofol and ketamine can give better hemodynamic stability during the induction and maintenance of general anesthesia than propofol used with fentanyl, whose cardiodepressant actions may cumulate. METHODS. For induction of general anesthesia 10 patients (ASA I and II) each received 3-5 boluses of propofol (0.5 mg.kg-1 during 35 s until predetermined level of anesthesia was reached (stage D2/E0 according to [20]) followed by a continuous propofol infusion (0.120 mg.kg-1.min). Fentanyl 0.1 mg was administered to each patient in group A for induction of anesthesia and again if evident pain was present. In group B ketamine was given following a pharmacokinetic model based on computer-simulated calculation. After an initial bolus of 38 mg injected within 2 min further doses of 42 mg, 35 mg, 32 mg and 28 mg ketamine were administered over 30 min at a time. Signs of evident pain were treated by means of supplementary doses of 0.5 mg.kg-1. RESULTS. In both groups a moderate drop of MAP was observed after the induction of general anesthesia. Two patients in each group showed a distinct decrease in MAP (-32%). The heart rate dropped slightly (-9%) in group A, but did not change in group B. Following intubation the MAP rose by less in group A (+8%) than in group B (+21%). After the beginning of the operation the group treated with propofol/fentanyl showed major hemodynamic changes; in particular, bradycardia with less than 40 bpm was observed in more patients than in the propofol/ketamine group. Postoperatively, fewer patients in group B required rescue doses of analgesics (1 of 10) than these in group A (7 of 10), though vigilance was better in group B. DISCUSSION. The dose of ketamine administered during the induction of general anesthesia may have been not high enough to neutralize the cardiodepressant effect of propofol. But during the maintenance of anesthesia there was in fact better hemodynamic stability in group B than in group A as a result of the neutralization of opposing actions. Fentanyl even intensified the fall in MAP after propofol. Patients in group B showed better vigilance as well as better pain relief postoperatively. The population of the fentanyl group was obviously more deeply sedated and analgesia was still inadequate. In our study general intravenous anesthesia with propofol and ketamine offered the advantages of better analgesia, a higher state of vigilance and the absence of respiratory depression during the postoperative phase compared with the combination of propofol and fentanyl.
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PMID:[The effect of propofol-ketamine anesthesia on hemodynamics and analgesia in comparison with propofol-fentanyl]. 207 45

The effect of ketamine infusion to control the intractable pain which had not responded to ordinary procedures in 12 patients with advanced cancer were evaluated. Ketamine 250 mg or 500 mg in 500 ml of transfusion fluid with or without 10 to 20 mg of droperidol was administered intravenously at the rate of 3 to 20mg of ketamine per hour. The pain scores by VAS in most of the patients decreased significantly with an averaged value of 8.3 before the treatment to 1 during the procedure. The durations of this therapy lasted from over 6 hours to 48 days. Slight disorientation in one patient and drowsiness in 5 were seen during the infusion. No cardiovascular or respiratory complications were noted. These results indicate that ketamine infusion is a useful therapeutic procedure to treat cancer pain which resist ordinary pain therapies.
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PMID:[Ketamine infusion for control of pain in patients with advanced cancer]. 225 43

There were different opinions about whether ketamine has an antagonistic effect on electroacupuncture (EA) analgesia. The aim of this paper was to investigate the effect of ketamine on EA. The rats were divided into three groups: 4 mg/kg, 20 mg/kg of ketamine in doses, and normal saline groups. Ketamine was injected peritoneally in dosage of 4 mg/kg and 20 mg/kg respectively. Tail flick latency (TFL) and vocalization threshold (VT) were taken as the indices of pain responses. Changqiang and Yaoshu acupoints were selected for electroacupuncture. It was observed that the analgesia effects of EA were attenuated after injection of ketamine either in 4 mg/kg group of 20 mg/kg group. The results indicate that 4 mg/kg or 20 mg/kg ketamine in doses has an antagonistic effect on EA analgesia, suggesting that attention should be paid to the dosage when ketamine is used for EA analgesia.
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PMID:[Effect of ketamine on acupuncture analgesia]. 251 6

A series consisting of 32 women undergoing total abdominal hysterectomy received a standard narcotic-free anaesthetic. For the first 24 h postoperatively, eight were given the standard regimen of intramuscular morphine sulphate whilst the other three groups received continuous subcutaneous infusions of either morphine sulphate, ketamine hydrochloride or the two drugs combined. The amount of time they were pain free, the incidence of sleep and nausea, together with cardiovascular and respiratory changes were recorded. All three subcutaneous regimens produced significantly more pain-free readings than intramuscular morphine, but ketamine resulted in higher respiratory rates and less sleepiness. No patient reported psychomimetic side effects, but ketamine on its own produced feelings of malaise in three patients on the second postoperative day. Subcutaneous infusions provide better postoperative analgesia than intermittent intramuscular morphine. Ketamine on its own cannot be advocated, but combined with morphine it allows a single infusion rate to be used for all patients, decreasing the need for nursing and medical involvement.
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PMID:Subcutaneous ketamine analgesia: postoperative analgesia using subcutaneous infusions of ketamine and morphine. 277 59

Ketamine is an injectable anesthetic agent that has been shown to interact as an agonist at opiate receptors. In addition, its antinociceptive action in rats is antagonized by the narcotic receptor antagonist naloxone. Thus it was assumed that the anesthetic may activate the pain inhibitory pathway, originating in the periaqueductal gray (PAG) and descending into the spinal cord, in a manner similar to that of narcotics like morphine. In the present study, it was verified that the systemic administration of naloxone (3 mg/kg i.p.) antagonized the elevation in tail-flick latency produced by an anesthetic dose of ketamine (160 mg/kg i.p.), but did not alter the duration of anesthesia (defined as duration of the loss of the righting reflex). However, when naloxone (3 micrograms/0.5 microliter/30 sec) was given by microinjection into the PAG it was found to be ineffective against the ketamine-induced elevation of the tail-flick latency. In contrast, the microinjection of the antagonist significantly attenuated (halved) the elevated latency in response to systemically administered morphine (4 mg/kg s.c.). It was also shown that ketamine was unable to elicit an increase in the latency of the tail-flick reflex when administered directly into the PAG over a wide range (0.10-100 micrograms) of doses. On the other hand, a local anesthetic-like effect of ketamine, known to occur when the drug is used in high concentration, was observed when doses exceeding 0.1 microgram were injected into the PAG. This action interfered with opiate actions in the PAG and made data from the microinjection studies difficult to interpret. The descending, pain inhibitory neuronal system originating in the PAG does not appear to participate in the antinociceptive action of ketamine measured by the tail-flick reflex. Perhaps the drug's effects are associated with alternative opiate mechanisms and/or opiate receptor subtypes not present on the cells of origin of the descending nerves within the PAG.
Pain 1985 Mar
PMID:Ketamine analgesia is not related to an opiate action in the periaqueductal gray region of the rat brain. 298 72


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