• The Korean Journal of Pain
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• v.18 no.2
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• pp.138-141
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• 2005

Background: There have been many attempts to alleviate pain after surgery, but there is no common approach to the control of postoperative pain. The use of epidural opioids, with local anesthetics, has been a widely employed formula to date. Ketamine, an N-methyl-d-aspartate receptor antagonist, has an excellent analgesic effect. Although there have been many reports on the dose and route of administrating analgesics, there have been few concerning the continuous epidural infusion of ketamine with fentanyl. We designed this study to find the effects of ketamine compared to those of epidurally injected bupivacaine and fentanyl, and used this trial to study any potential side effects. Methods: In a double blind trial, 55 patients received either fentanyl, $0.3{\mu}g/kg/h$ (Group F), or fentanyl, $0.3{\mu}g/kg/h$, and ketamine, 0.1 mg/kg/h (Group FK), added to 0.125% bupivacaine, at rates as high as 2 ml/h, for patient controlled epidural analgesia (PCEA) following a transabdominal hysterectomy. Ten minutes before the operation, patients received 10 ml of 0.125% bupivacaine, with either 0.5 mg/kg ketamine or the same amount of normal saline with $50{\mu}g$ fentanyl added. The pain scores and the side effects were recorded at 1, 3, 6 and 24 hour post operation. Results: There were no differences in the pain scores or side effects between the two groups. Conclusions: We failed to find any effect of the addition of epidural ketamine compared to the that of the bupivacaine and fentanyl formula. However, it is suggested that further investigations will be required on the dose and route of administration.

• The Korean Journal of Pain
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• v.19 no.1
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• pp.87-90
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• 2006

Background: There are many ways to provide superior analgesia for postoperative pain after abdominal surgery of which epidural analgesics with opioids and local analgesics are the most useful. In an effort to maximize the level of analgesia and to minimize the side effects, ketamine, midazolam, clonidine, and adrenalin can be co-administrated as an adjuvant. This study examined the analgesic effect and side effects of midazolam compared with those given an epidural injection of bupivacaine, fentanyl and ketamine. Methods: In a double blind randomized controlled trial, 50 patients received either fentanyl $0.3{\mu}g/kg/h$ and ketamine 0.1 mg/kg/h (Group FK) or fentanyl $0.3{\mu}g/kg/h$, ketamine 0.1 mg/kg/h and midazolam 0.4 mg/h (Group FKM), added to 0.125% of bupivacaine at a rate of as much as 2 ml/h, for patient controlled epidural analgesia (PCEA) after low abdominal surgery. Ten minutes before surgery, the patients received either 10 ml of 0.125% bupivacaine with 0.5 mg/kg of ketamine or 10 ml of 0.125% bupivacaine with the same amount of normal saline, added to fentanyl $50{\mu}g$. The pain score and the side effects were recorded at 1, 3, 6, and 24 hours after surgery. Results: There was no difference in the pain score except for the VAS on coughing 1 hour after surgery. FKM group had fewer side effects. Conclusions: There was a better analgesic effect and fewer side effects with the addition of epidural midazolam to bupivacaine and fentanyl with ketamine formula. However, more study on the dose and route of administration will be needed.

• The Korean Journal of Pain
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• v.1 no.1
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• pp.87-90
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• 1988

In recent years the use of epidural opiates has increased and although this method of pain relief has shown good results in clinical practice It is still subject to certain drawbacks, the most serious of which appears to be delayed respiratory depression. Since ketamine administered systemically is unlikely to produce respiratory depression it seemed worthwhile to investigate the possibility of exploiting the potent analgesic property to ketamine by its epidural administration. The analgesic effect of ketamine 4 mg, administered epidural space, was evaluated. The duration of pain relief varied from less than 3 hours in 20% to over 24 hours in 30% of the cases. In 62.5% of the cases pain relief exceeded 6 hours. There was no evidence of respiratory depression, and there no postoperative neurologic sequelae. The present results indicated the need for further studies to compare the efficacy and safety of epidural ketamine with the response to epidural opioids for the relief of postoperative pain.

• The Korean Journal of Pain
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• v.18 no.1
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• pp.39-42
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• 2005

Background: Besides its general anesthetic effect, ketamine interacts with sodium channels in a local anesthetic-like fashion, including the sharing of binding sites with those commonly used by clinical local anesthetics. This study evaluated the dose related effects of ketamine during epidural anesthesia with 0.5% ropivacaine. Methods: Sixty ASA physical status I II patients, scheduled for minor elective surgery under epidural anesthesia using 0.5% ropivacaine, were randomly divided into three groups (n = 20 each). The patients initially received either 0.5% ropivacaine (group 1), ketamine (0.1 mg/kg) in addition to the epidural 0.5% ropivacaine (group 2) or ketamine (0.2 mg/kg) in addition to the epidural 0.5% ropivacaine (group 3). The regression of sensory block was assessed by transcutaneous electric stimulation (TES), equivalent to a surgical incision. Motor block was assessed using the Modified Bromage's scale. Episodes of bradycardia, hypotension and sedation were also recorded. Results: There were no significant differences among the three groups in the maximal levels of sensory block or the times taken for these levels to be reached. The mean times for the block to regress to two and four segments below the maximal level were significantly prolonged by epidural ketamine. Conclusions: Epidural ketamine prolongs the duration of ropivacaine epidural anesthesia. These results suggest that ketamine has local anesthetic-like actions.

• The Korean Journal of Pain
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• v.13 no.2
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• pp.251-254
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• 2000

A 20-year-old male patient developed severe right leg pain, hyperesthesia and allodynia after multiple lumbar epidural blocks. His pain was neuropathic pain (complex regional pain syndrome type I). The patient was treated with repeated administration of epidural ketamine at the rate of 0.2~0.7 mg/kg on multiple occasions. Complete relief of pain was achieved.

• The Korean Journal of Pain
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• v.12 no.2
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• pp.205-210
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• 1999

Background: Epidural morphine for postoperative pain control has a serious risk of respiratory depression and other side effects such as pruritus, nausea and urinary retention. In recent years, it is known that epidural administration of ketamine potentiates the effect of epidural morphine, and so decrease the side effects of epidural morphine. This study was performed to evaluate the analgesic efficacy of epidurally administered ketamine and whether this epidural administration can decrease the amount of epidural morphine. Methods: Sixty patients scheduled for the elective cesarean section were randomly selected. All patients were given subarachnoid injection of tetracaine 9 mg. Group I received epidural bolus injection of 0.15% bupivacaine 10 ml with morphine 2 mg followed by a continuous infusion of 0.125% bupivacaine 100 ml containing morphine 4 mg after peritoneum closure, and group II received the same method as group I except for the addition of epidural ketamine 30 mg. Analgesic effects were assessed using Numeric Rating Score (NRS) and Prince Henry Score (PHS). Also, the degree of satisfaction and the incidence of the side effects were observed. Results: Analgesic effects were significant in both groups after drug administration. But NRS and PHS were not significantly different between two groups at all times. The incidence of nausea and vomiting was 11 out of 30 in group I and 9 out of 30 in group II and the incidence of itching was 11 out of 30 in group I and 8 out of 30 in group II. Number of patients using additional analgesics were 2 and 1 in group I and II, respectively. Conclusions: Epidural ketamine did not potentiate the analgesic effect of epidural morphine and could not decrease the side effect of epidural morphine.

• The Korean Journal of Pain
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• v.1 no.2
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• pp.192-198
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• 1988

Sixty patients, of ASA physical status class I for elective operations in the lower abdomen, perineum, or lower extremities, were studied in a comparative prospective trial to evaluate the efficacy of epidural morphine and ketamine for postoperative analgesia. They were divided into two groups: an epidural morphine sulfate group (EMS group; 30 patients), and an epidural ketamine hydrochloride group (EKH group; 30 patients). Indwelling epidural catheters were placed in the patients' lumber areas (L3-4) and then all patients were anesthetized with thiopental, nitrous oxide, and halothane. After the patients had fully recovered from the anesthesia, the analgesic agents were administered epidurally via the catheter when the patients complained of pain in the postoperative period. The groups were given either 0.1 mg/kg of morphine sulfate or 0.5 mg/kg of ketamine hydrochloride administered in a volume of 10 ml of normal saline. Patients were observed for the onset and duration of postoperative analgesia and for other effects. Total doses were $5.7{\pm}0.6\;mg$ of morphine sulfate in the EMS group and $27.9{\pm}3.3\;mg$ of ketamine hydrochloride in the EKH group. The onset of analgesia was detectable within 35 min.($23.5{\pm}6.3$ min) in 86.7% (26 cases) of the EMS group and within 10 min. ($7.8{\pm}3.7$ min.) in 76.7% (23 cases) of the EKH group. Mean duration of postoperative analgesia was $22.3{\pm}2.1\;hr$. in the EMS group. In the EKH group, the duration of analgesia was shorter and variable, the range of duration was from 2 hr. to 24 hr., Cardiopulmonary changes were statistically insignificant ih both groups. Side effects such as nausea, vomiting, urinary retention, pruritus, dizziness, and headache were observed in EMS group. In the EKH group, there was no discomfort except dizziness (3 cases) and headache (1 case). Epidural ketamine was a safe technique for postoperative analgesia, but because of the variability and relative shortness in the duration of analgesia the use of this technique will require further clinical trials.

• The Korean Journal of Pain
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• v.19 no.1
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• pp.96-100
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• 2006

Pain control is very important in managing terminal cancer patients and there are several modalities to alleviate their pain. A high dosage of epidural morphine is effective to control terminal cancer pain. Furthermore, to decrease the amount of morphine, adding an alternative adjuvant like ketamine to the morphine regimen is considered helpful for controlling the pain of a terminal cancer patient. A 45 year old male patient with terminal lung cancer had neck pain that was caused by multiple bone metastases. Continuous epidural block was started with 2 mg/day of morphine and the dosage was gradually increased to 90 mg/day in 86 days. 30 mg/day of ketamine was then added to it. Overall, the morphine and ketamine dosages were increased to 564 mg/day and 140 mg/day, respectively, in 11 months until the patient expired. In this case, the high dosage of epidural morphine, 580 mg/day, was administered to control cancer pain without any severe adverse effects.

• The Korean Journal of Pain
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• v.13 no.1
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• pp.105-110
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• 2000

Central neuropathic pain may occur in 10~20% of the patients after spinal cord injury. The central pain syndrome include spontaneous continuing and intermittent pain as well as evoked pain. The pain is evoked by non-noxious stimulation of the region (allodynia) and repeated stimulation (wind-up phenomenon). Four patients were referred suffering from severe pain, allodynia and hyperaesthesia after spinal cord injury. They had received conventional treatment with non-steroidal anti-inflammatory drugs, steroid, anticonvulsant, antidepressant and rehabilitation which failed to provide pain relief. We administered combination of low doses of morphine and ketamine (10 mg) through the epidural catheter with other conventional therapy. Satisfactory pain relief was achieved in each patient. The reduction of pain was not associated with severe side effects. The most bothersome side effect of ketamine was dizziness in one patient, only caused by bolus injection (ketamine 10 mg with normal saline 10 ml). This suggests synergy from this combination that provides an alternative treatment for central pain.

• The Korean Journal of Pain
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• v.11 no.2
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• pp.294-298
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• 1998

The feature of neuropathic pain may occur in the absence of any apparent stimulus and be exaggerated in either amplitude or duration. Peripheral nerve injury may produce neuropathic pain and opioids have been shown to be relatively unsatisfactory for the treatment of most cases of neuropathic pain. The NMDA receptor system is involved in transmission and modulation of nociceptive information. We treated patients with severe pain, hyperaesthesia and allodynia with epidural injection of NMDA receptor antagonist, ketamine (10 mg) and morphine (0.5 mg) or other opioid. The combinations provided effective pain management in 23 patients with neuropathic pain.