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)

To identify the opioid antagonist activity of nalmefene and to determine its duration in man, six healthy male subjects were pretreated on separate days with a saline placebo, 0.5 mg, 1 mg, or 2 mg nalmefene intravenously in a randomized double-blind fashion. Opioid challenges with fentanyl, 2 micrograms/kg, then were administered 1, 2, 4, 6, and 8 h afterward. Respiratory depression was monitored by ventilatory and occlusion pressure responses during CO2 rebreathing, while analgesia to experimental pain was identified with the submaximal effort tourniquet ischemia test. One hour following placebo pretreatment, the initial fentanyl dose produced marked respiratory depression. Minute ventilation and occlusion pressure at a PCO2 60 mmHg during rebreathing (VE60 and P(0.1)60) were reduced to 29 and 41% of control, respectively. The slopes of the ventilatory and occlusion pressure responses also decreased significantly to 51 and 55% of control. Respiratory effects were similar with all subsequent fentanyl doses. Pretreatment with 2 mg nalmefene completely prevented the subjective and respiratory effects of fentanyl for the entire 8 h of the experiment. Nalmefene, 1 mg, significantly blunted the fentanyl effects for the same period, but VE60 values at 6 and 8 h were depressed significantly (P less than 0.05) to 66 and 61% of control. The antagonist effects of the lowest nalmefene dose, 0.5 mg, persisted for about 4 h, at which time VE60 was 64% of control. Fentanyl administration produced consistent increases in pain tolerance (44-55% above control) throughout the experiment. Nalmefene pretreatment abolished this analgesic response in a dose-related time course that mirrored the respiratory effects almost exactly.(ABSTRACT TRUNCATED AT 250 WORDS)
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PMID:Prolonged antagonism of opioid action with intravenous nalmefene in man. 394 4

Nalmefene is a long-acting opioid antagonist that provides long-term relief from side effects of intrathecal morphine sulfate. A randomized, double-blind, placebo-controlled study was conducted to determine whether prophylactic nalmefene could decrease side effects of intrathecal morphine given during cesarean section, without affecting analgesia. Sixty parturients were given 0.25 mg of intrathecal morphine, 12.5 micrograms of fentanyl, and 11.25 to 15 mg of bupivacaine. A dose of 0.25 microgram/kg of nalmefene or placebo was given by intravenous piggyback immediately after delivery of the neonate. Nausea, vomiting, pruritus, and level of sedation were assessed for a 24-hour period using a 4-point ordinal scoring system. Pain was assessed by using a 0- to 10-point verbal analogue scale. A 5-point analgesic satisfaction survey also was completed. Subjects who received nalmefene required supplemental analgesia at a median of 6.00 hours after intrathecal morphine, compared with 14.12 hours in the placebo group (P = .037). No differences were found between the groups in the incidence of pruritus, nausea and vomiting, level of sedation, or analgesic satisfaction. We concluded that nalmefene at a dose of 0.25 microgram/kg does not decrease the incidence of side effects but increases the need for supplemental analgesics.
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PMID:The impact of nalmefene on side effects due to intrathecal morphine at cesarean section. 1175 62

The aim of this study was to compare the severity of nausea and incidence of emesis in laboring parturients who received intravenous nalmefene or placebo following an intrathecal opioid (ITO). We randomly assigned 60 ASA class I or II multiparous women to receive nalmefene or placebo. Subjects received fentanyl, 25 micrograms, and morphine, 250 micrograms, intrathecally on request for analgesia. Thirty minutes after vaginal delivery, the experimental group received nalmefene, 20 micrograms, and the placebo group received an equivalent volume of normal saline intravenously. Visual analog scale nausea scores and data about episodes of emesis were obtained during labor and during the first 24 hours postpartum. There were no significant differences in age, weight, duration of labor, volume of intravenous fluids infused, time from last meal to delivery, or time from administration of the ITO to injection of the study drug. There were no significant differences in mean visual analog scale nausea scores or frequency of emesis for any time interval. Nalmefene, 20 micrograms, given intravenously within 30 minutes of vaginal delivery does not significantly reduce the nausea and vomiting associated with the use of ITOs for labor analgesia.
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PMID:The use of nalmefene for intrathecal opioid-associated nausea in postpartum patients. 1188 46