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

Pain and its treatment are known to have adverse effects on the organism, including deterioration in myocardial, diaphragmatic, and small bowel function. The provision of adequate intravenous analgesia, and the choice of agent, can ameliorate or exacerbate these manifestations of the stress response. The choice of agent, opioid or non-opioid, has in some respects become more difficult as more information has become available regarding the merits and adverse effects of each. Increased awareness of the frequency of hypoxemia secondary to the opioids' ability to cause an obstructive sleep apnea picture, and the cost efficiency of ketorolac through a reduction in opioid toxicity, contrast with recent studies which suggest that the gastrotoxic and nephrotoxic effects of ketorolac may occur earlier than previously suspected. The suitability of using the dissociative anesthetic agent ketamine in critically ill patients remains to be proven. Ketamine provides intense analgesia at subanesthetic doses. Its centrally mediated sympathomimetic action encourages hemodynamic stability, and it is relatively devoid of respiratory depressant activity. Increasing experience with ketamine outside the operating room has resulted in its successful use in cases of severe bronchospasm and status epilepticus.
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PMID:Intravenous analgesia. 992 88

We examined the role of N-methyl-D-aspartate (NMDA) receptors in chronic (pathological) pain in humans by using the NMDA receptor antagonist ketamine as a probe. Thirty patients with neuropathic pain in the trigeminal area were given an i.m. injection of ketamine 0.4 mg/kg combined with midazolam 0.05 mg/kg. Pethidine 1.0 mg/kg served as a control. Three different response patterns were observed. Ketamine caused a long-term (6-24 h) analgesic effect partly dissociated from the mental side effects in 8 of the 26 patients who completed the study; these patients also had a slight analgesic effect of pethidine. In nine patients, ketamine caused a short-lasting (<2 h) analgesic effect closely associated with the mental side effects, whereas pethidine caused little or no analgesia. The remaining nine patients did not experience any reduction of pain after either drug in spite of characteristic side effects. One week after the i.m. challenge the patients received either 4.0 mg/kg ketamine hydrochloride or placebo capsules to be taken orally as a nightly dose for three consecutive nights. Five of the eight patients who had a long-term analgesic effect of the i.m. challenge reported decreased pain on days after ketamine. None of the others reported an analgesic effect. The phenomenon of long-term depression of pain in a subgroup of patients was thus confirmed when ketamine was given p.o. These findings indicate that NMDA receptors are involved in the perception and maintenance of pathological pain in some patients. In others, pain appears to be mediated by NMDA receptor-independent mechanisms. We suggest that NMDA receptor-independent transmission in central pain pathways may contribute to the reduced efficiency of analgesic drugs often seen in chronic pain states.
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PMID:Prolonged analgesic effect of ketamine, an N-methyl-D-aspartate receptor inhibitor, in patients with chronic pain. 1021 88

Ketamine is a noncompetitive N-methyl-D-aspartate (NMDA) receptor antagonist used recently for analgesia in patients with chronic pain. Twenty one patients with chronic neuropathic pain were treated with oral ketamine starting at a divided dose of 100 mg/day and titrating upwards by 40 mg/day until efficacy was reached, or until side effects became limiting. A retrospective chart review was conducted to evaluate the analgesic efficacy and side effects of the treatment. Nine patients discontinued ketamine because of intolerable side effects, four patients experienced few or no side effects but had no discernible benefit, four others had equivocal responses. Four patients have continued oral ketamine for long periods. One patient has had no significant benefit or side effects but continues to use ketamine 500 mg/day and three people have used doses ranging from 100-240 mg day for over 1 year duration and have reported improvements in pain and decreased use of analgesics. The analgesic benefits of ketamine appeared to be most pronounced in, but not limited to, patients with pain histories of less than 5 years.
J Pain Symptom Manage 1999 May
PMID:Clinical experience with oral ketamine. 1068 20

Ketamine is an injectable anesthetic induction agent that has been reported to have analgesic activity in pain from a variety of mechanisms, but predominantly in neuralgic and dysesthetic neuropathic pain. In this case report we illustrate the effectiveness of ketamine in a patient with neuropathic pain resulting from cauda equina trauma. Among the issues addressed are the role of pretreatment with haloperidol to prevent ketamine-induced psychomimetic effects, the potential for fewer side effects and a need for lower doses when ketamine is administered orally, and the need for further study regarding appropriate monitoring parameters during the titration phase. Oral ketamine can be effective in treatment refractory chronic neuropathic pain of spinal origin.
J Pain Symptom Manage 1999 Jul
PMID:Analgesic effect of oral ketamine in chronic neuropathic pain of spinal origin: a case report. 1043 75

Ketamine, a selective, noncompetitive N-methyl-D-aspartate (NMDA)-receptor antagonist, is able to alter pain perception at the spinal level. Little clinical data exist on the intrathecal and epidural use of ketamine in chronic pain. Histopathologic findings after intrathecal injection of ketamine with and without preservatives are rarely reported. This outcome was evaluated in a 72-year-old woman with abdominal pain due to cancer who was treated with the intrathecal application of bupivacaine, clonidine, and morphine. We reached satisfactory pain relief with the addition of ketamine to the mixture for 7 days. On postmortem, focal lymphocytic vasculitis close to the catheter injection site was found. This finding has not been described previously after long-term application of ketamine intrathecally. The intrathecal infusion of ketamine with preservative, or the mixture of ketamine, clonidine, morphine, and bupivacaine resulted in isolated lymphocytic vasculitis of the spinal cord and leptomeninges without any clinical signs of neurological deficit.
J Pain Symptom Manage 1999 Sep
PMID:Histological findings after long-term infusion of intrathecal ketamine for chronic pain: a case report. 1051 45

Ketamine is known to have distinguished analgesic effects without anesthetic when administered in a low dose. Since ketamine is not commercially available except injection forms, we prepared ketamine tablets for the home-care medication of patients with neuropathic pain. The direct compression or wet granulation method was employed to form 150 mg of tablets containing 50 mg of ketamine. The latter method was superior to the former one in terms of content uniformity, weight variation and disintegration tests of the tablets. Ketamine contents in the tablet prepared by the wet granulation method were unchanged for 12 weeks under the conditions of 25 degrees C and 75% relative humidity (RH). The Cmax and AUC0-3 h values for ketamine after administration of the tablet were slightly smaller than those of the syrup in a healthy volunteer. However, analgesic effects of the tablet was similar to that of the syrup in a patient with neuropathic pain. And the tablet was also effective for another four patients with neuropathic pain. These results indicate that ketamine tablets are useful for the home-care medication of patients with neuropathic pain.
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PMID:[Preparation of ketamine tablets for treatment of patients with neuropathic pain]. 1063 Jan 3

We have examined the effect of systemic administration of ketamine and lidocaine on brush-evoked (dynamic) pain and punctate-evoked (static) hyperalgesia induced by capsaicin. In a randomized, double-blind, placebo-controlled, crossover study, we studied 12 volunteers in three experiments. Capsaicin 100 micrograms was injected intradermally on the volar forearm followed by an i.v. infusion of ketamine (bolus 0.1 mg kg-1 over 10 min followed by infusion of 7 micrograms kg-1 min-1), lidocaine 5 mg kg-1 or saline for 50 min. Infusion started 15 min after injection of capsaicin. The following were measured: spontaneous pain, pain evoked by punctate and brush stimuli (VAS), and areas of brush-evoked and punctate-evoked hyperalgesia. Ketamine reduced both the area of brush-evoked and punctate-evoked hyperalgesia significantly and it tended to reduce brush-evoked pain. Lidocaine reduced the area of punctate-evoked hyperalgesia significantly. It tended to reduce VAS scores of spontaneous pain but had no effect on evoked pain. The differential effects of ketamine and lidocaine on static and dynamic hyperalgesia suggest that the two types of hyperalgesia are mediated by separate mechanisms and have a distinct pharmacology.
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PMID:Differential effects of systemically administered ketamine and lidocaine on dynamic and static hyperalgesia induced by intradermal capsaicin in humans. 1074 46

Central mechanisms related to referred muscle pain and temporal summation of muscular nociceptive activity are facilitated in fibromyalgia syndrome (FMS) patients. The present study assessed the effects of an NMDA-antagonist (ketamine) on these central mechanisms. FMS patients received either i.v. placebo or ketamine (0.3 mg/kg, Ketalar((R))50% decrease in pain intensity at rest by active drug on two consecutive VAS assessments). Fifteen out of 17 ketamine-responders were included in the second part of the study. Before and after ketamine or placebo, experimental local and referred pain was induced by intramuscular (i.m.) infusion of hypertonic saline (0.7 ml, 5%) into the tibialis anterior (TA) muscle. The saline-induced pain intensity was assessed on an electronic VAS, and the distribution of pain drawn by the subject. In addition, the pain threshold (PT) to i.m. electrical stimulation was determined for single stimulus and five repeated (2 Hz, temporal summation) stimuli. The pressure PT of the TA muscle was determined, and the pressure PT and pressure pain tolerance threshold were determined at three bilaterally located tenderpoints (knee, epicondyle, and mid upper trapezius). VAS scores of pain at rest were progressively reduced during ketamine infusion compared with placebo infusion. Pain intensity (area under the VAS curve) to the post-drug infusion of hypertonic saline was reduced by ketamine (-18. 4+/-0.3% of pre-drug VAS area) compared with placebo (29.9+/-18.8%, P<0.02). Local and referred pain areas were reduced by ketamine (-12. 0+/-14.6% of pre-drug pain areas) compared with placebo (126.3+/-83. 2%, P<0.03). Ketamine had no significant effect on the PT to single i.m. electrical stimulation. However, the span between the PT to single and repeated i.m. stimuli was significantly decreased by the ketamine (-42.3+/-15.0% of pre-drug PT) compared with placebo (50. 5+/-49.2%, P<0.03) indicating a predominant effect on temporal summation. Mean pressure pain tolerance from the three paired tenderpoints was increased by ketamine (16.6+/-6.2% of pre-drug thresholds) compared with placebo (-2.3+/-4.9%, P<0.009). The pressure PT at the TA muscle was increased after ketamine (42.4+/-9. 2% of pre-drug PT) compared with placebo (7.0+/-6.6%, P<0.011). The present study showed that mechanisms involved in referred pain, temporal summation, muscular hyperalgesia, and muscle pain at rest were attenuated by the NMDA-antagonist in FMS patients. It suggested a link between central hyperexcitability and the mechanisms for facilitated referred pain and temporal summation in a sub-group of the fibromyalgia syndrome patients. Whether this is specific for FMS patients or a general phenomena in painful musculoskeletal disorders is not known.
Pain 2000 Apr
PMID:Ketamine reduces muscle pain, temporal summation, and referred pain in fibromyalgia patients. 1078 23

Ketamine is a drug widely used for analgesia and sedation of children for diagnostic and therapeutic procedures. The authors investigated in a randomized controlled clinical trial if diazepam premedication would have a beneficial effect on side effects related to ketamine anesthesia for bone marrow punctures (BMPs) in children with acute lymphoblastic leukemia (ALL). Sixteen children 4 years or older at the time of BMP were eligible. The first 2 BMPs after complete remission was obtained were studied. BMPs were performed under ketamine anesthesia (1.0-1.5 mg/kg i.v.), as usual. Patients were randomized to receive 1 h before the first BMP blinded, either diazepam or placebo orally and before the second BMP the other way round. Blood pressure, heart rate, and oxygen saturation were monitored, and patients were observed for signs of anxiety, pain, and other side effects. The patients were interviewed after each BMP and asked for their preference 1 week after the second BMP. Ketamine anesthesia appeared as safe and effective after diazepam premedication as after placebo premedication. From the interviews and questionnaires, it was clear that half of the children preferred diazepam premedication because of less awful dreaming and more gradual falling asleep and waking up. Diazepam premedication may be useful for selected children with ALL receiving ketamine anesthesia for BMPs.
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PMID:Ketamine anesthesia with or without diazepam premedication for bone marrow punctures in children with acute lymphoblastic leukemia. 1091 48

An overview of the spinal administration of ketamine is presented. Ketamine acts as a noncompetitive antagonist of the NMDA receptor Ca(++ channel pore. This effect provides interesting possibilities in pain therapy. However, there are still contrasting results that seem to be due to a lack of comparative controlled studies. The presence of systemic and neurotoxic effects presently limits clinical use).
Curr Rev Pain 1999
PMID:The Epidural and Intrathecal Administration of Ketamine. 1099 5


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