***TASK*** the task is to summarize an input biomedical literature in six sentences 
    ***INPUT*** the input is a biomedical literature 
    ***OUTPUT*** the output is the summary of an input biomedical literature in six sentences 
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    Input: We have studied the effect of propofol on the side effects associated with intrathecal morphine in 40 patients undergoing major arthroplasty . Patients received spinal anaesthesia with plain 0.5 % bupivacaine 20 mg mixed with preservative-free morphine 0.3 mg . Before injection of the local anaesthetic , the patients were allocated r and omly to receive either a bolus dose of propofol 10 mg followed by an infusion of 30 mg/24 h or equal volumes of 10 % Intralipid ( control group ) . The number of patients without postoperative nausea and vomiting ( PONV ) was similar in both groups . However , the incidence of nausea and vomiting was lower in the propofol ( 13 and 22 , respectively ) than in the control ( 34 and 36 ) group ( P < 0.01 and P < 0.05 , respectively ) . Severe vomiting episodes were less frequent in the propofol group ( 1 vs 11 ; P < 0.05 ) . Four patients in the propofol group and 12 patients in the control group had itching ( P < 0.05 ) . The incidence of urinary retention was similar in both groups . There was no additional sedation attributable to propofol . In conclusion , sub-hypnotic doses of propofol protected significantly against itching and had a modest effect on PONV after intrathecal morphine The purpose of this study was to determine whether subhypnotic doses of propofol effectively relieve pruritus in women who received intrathecal morphine for postoperative analgesia after cesarean delivery . Twenty-nine women who developed pruritus after undergoing an elective cesarean section and receiving intrathecal morphine ( 0.25 mg ) for postoperative analgesia were enrolled in this r and omized , prospect i ve , double-blind study . The women were r and omly assigned to receive either 1 mL of propofol ( n=17 ) or 1 mL of placebo ( n=12 ) IV . Pruritus was evaluated 5 min after treatment . In the absence of successful treatment , the women received another 1 mL of the same drug . Pruritus was again evaluated 5 min after the second dose . We found that pruritus was successfully treated twice in the propofol group and once in the placebo group ( P = not significant ) . The antipruritic action of propofol lasted for up to 6 h in one woman and 15 min in the other . The one success in the placebo group lasted for 15 min . We conclude that the success rate of propofol in treating  pruritus in women who received intrathecal morphine for postoperative analgesia after cesarean delivery is not significantly different from that of placebo . Implication s : Pruritus is a common and bothersome side effect of neuraxial opioids after cesarean section . Subhypnotic doses of IV propofol ( 10 mg ) have been used to treat pruritus caused by neuraxial opioids . In this prospect i ve , r and omized , double-blind study , we found that propofol does not relieve pruritus in women who underwent cesarean section and received intrathecal morphine sulfate ( 0.25 mg ) for postoperative pain relief . ( Anesth Analg 1998;86:310 - 3 In order to evaluate the effect of preventive corticosteroid on the occurrence of pruritus after epidural anesthesia with morphine , we studied 95 patients undergoing cesarean section . Thirty-seven patients ( group I ) were given 20 mg of bupivacaine 0.5 % for the operation and 2 mg of morphine hydrochloride with 50 mg of Ultracortene-H immediately after the operation and 24 h later , and 58 patients ( group II ) were given epidural bupivacaine during the operation and epidural morphine hydrochloride immediately after the operation and 24 h later without Ultracortene-H. Only 8.1 % of group I patients had pruritus after the injection compared to 20.6 % in group II . We suggest that the addition of 50 mg Ultracortene-H to 2 mg epidural morphine analgesia after the operation might prevent severe forms of pruritus A majority of patients experience pruritus , nausea and /or emesis following epidural morphine administration post-cesarean section .  Naloxone or diphenhydramine are commonly used to treat these side effects . Prevention or reduction in the incidence of side effects of epidural morphine is a clinical goal . The purpose of the study was to observe the efficacy of prophylactic administration of hydroxyzine on the incidence and severity of pruritus following the epidural administration of morphine in 40 patients who requested epidural morphine for postoperative pain relief . Group I ( n = 20 ) received saline , while Group II ( n = 20 ) received 50 mg of hydroxyzine ten minutes after the administration of 5 mg epidural morphine . Both solutions were administered by deep intramuscular injection in the thigh area . The results of this investigation demonstrated that hydroxyzine was efficacious in attenuating the incidence of severe pruritus Background and Objectives . Epidural morphine is accepted as an efficient means of postoperative pain management . However , development of side effects such as nausea and vomiting and pruritus has been reported . This study compared the efficacy of intravenous infusions of nalbuphine or naloxone in the prevention of epidural morphine‐related side effects . Methods . Seventy‐five female patients undergoing epidural anesthesia for total hysterectomy were enrolled in a r and omized , double‐blind study . At the end of the surgery , all patients received epidural 3 mg morphine ( every 12 hours ) for postoperative pain . Meanwhile , patients in group 1 received an adjuvant intravenous infusion of nalbuphine 60 μg/kg/h , patients in group 2 received intravenous infusion of naloxone 2 μg/kg/h , and patients in group 3 received intravenous saline infusion only . A rescue analgesic of intramuscular 50 mg meperidine ( every 4 hours ) was available for each patient . Patients were observed for 24 hours . Results . All patients had adequate postoperative pain relief . However , the proportion of patients requiring rescue analgesia and the total consumption of rescue analgesic were higher in group 2 than in the other two groups . The incidence of nausea and vomiting and pruritus was higher in group 3 than in the other two groups . Conclusions . We found that coadministration of either nalbuphine or naloxone with epidural morphine reduces the incidence of morphine‐related side effects . However , unlike naloxone , nalbuphine did not attenuate the analgesic effect of epidural morphine This study was design ed to evaluate the efficacy of nalmefene vs. naloxone in preventing side effects result ing from intrathecal opioids , in patients undergoing cesarean delivery . Eighty patients who were scheduled for elective cesarean delivery under spinal anesthesia were included in a double-blind , placebo-controlled study . Patients were r and omized into four groups : saline ; intravenous nalmefene 0.25 micro.kg(-1 ) every 12 h x 2 ; intravenous nalmefene 0.5 microg.kg(-1 ) every 12 h x 2 ; and naloxone infusion 48 microg.h(-1 ) ( 1.2 microg.ml(-1 ) ) . There were no significant differences among the groups with respect to pain , sedation , satisfaction , or the occurrence or treatment of pruritus or nausea . There was a significant difference among the groups with respect to the occurrence of vomiting ( P < 0.03 ) : both nalmefene groups had a higher rate of vomiting than did the control group ; the 0.25 microg.kg(-1 ) nalmefene group had a higher rate than did the naloxone group . The use of narcotic antagonists does not result in improved comfort in obstetrical patients receiving intrathecal morphine and fentanyl Background and Objectives Because the mechanism of inhibition of epidural morphine-induced pruritus by droperidol is not clear , this study was undertaken to determine the effects of larger doses of droperidol or morphine , or both . Methods A double-blind study was performed in 210 ASA I or II patients undergoing cesarean delivery , who were r and omly assigned to six groups . All patients received epidural anesthesia with 0.5 % bupivacaine containing 1:200,000 epinephrine , to which 2 mg ( groups 1 , 2 , and 3 ) or 4 mg ( groups 4 , 5 , and 6 ) morphine sulfate was added . Just after delivery , 2.5 mg droperidol was given intravenously to groups 2 and 5 , and 5 mg was given to groups 3 and 6 . During the postoperative period , the patients were assessed for the occurrence and severity of pruritus ( classified as absent , mild , moderate , or severe ) or other untoward symptoms . The groups were compared for the incidence of pruritus by the Mann-Whitney nonparametric test . Results The incidence of pruritus was significantly reduced only when the control group ( no droperidol ) was compared with the group that received 2.5 mg droperidol , both when 2 mg and when 4 mg morphine was used . A 5-mg dose of droperidol had no inhibitory effect . There was no difference in the incidence of pruritus between use of 2 mg and 4 mg morphine . Other untoward effects of morphine either could not be observed or occurred with an incidence unaffected by either dose of droperidol . Conclusion Pruritus caused by epidural use of 2 or 4 mg of morphine is inhibited by the intravenous use of 2.5 mg droperidol but not by a larger dose Propofol is associated with a low incidence of postoperative nausea and vomiting . In a prospect i ve , r and omized , double-blind , placebo-controlled study , we investigated the possible direct antiemetic properties of a subhypnotic dose of propofol .  Fifty-two ASA physical status I or II patients , aged 15–60 yr with nausea and vomiting after minor gynecologic , orthopedic , or digestive tract surgery , were included in the study and received either propofol ( 10 mg = 1 mL ) or placebo ( 1 mL Intralipid ) intravenously in the postanesthesia care unit . Patients treated with propofol experienced a larger reduction in nausea and vomiting than patients treated with placebo ( 81 % vs 35 % success rate ; P < 0.05 ) . Patients successfully treated had a similar incidence of relapse  ( propofol 28 % ; placebo 22 % ) within the first 30 min after therapy . Thirty-three percent of the propofol-treated patients and 44 % of the placebo-treated patients showed a minor increase in sedation . The level of postoperative pain did not change in either group . Hemodynamic values remained unchanged in both groups . Pain on injection ( 7.6 % ) or dizziness ( 3.6 % ) only occurred in the propofol group . We conclude that propofol has significant direct antiemetic properties The influence of two different concentrations of iv naloxone infusion on the analgesia and adverse effects of epidural morphine were compared in a double-blind , placebo-controlled study . Fortyfive patients undergoing gallbladder surgery were provided postoperative analgesia by 4 mg epidural morphine ; they then received an iv infusion over a 12-h period consisting of either 5 μg · kg−1 · h−1 naloxone , 10 μg · kg−1 · h−1 naloxone , or saline .  Pain relief was assessed by hourly visual analog scoring ( VAS ) and by direct question ing of the patient . Requirement of additional analgesia was noted . Respiratory frequency was monitored every 15 min and arterial blood gases were analyzed every 2 h for 24 h. Peak expiratory flow ( PEF ) was recorded 6 and 24 h postoperatively . Steady-state kinetics of naloxone were determined by a modified radioimmunoassay ( RIA ) method . All patients had good to excellent postoperative pain relief . Naloxone , 5 μg · kg−1 · h−1 , did not appear to have any effect on epidural morphine analgesia . However , naloxone infusion at the rate of 10 μg.kg−1 h−1 reduced the duration of analgesia by about 25 % , and more frequent injections of epidural morphine were required to give effective analgesia . Complete reversal of analgesia was not seen in any patient . A dose-related stimulatory effect on respiratory frequency was noted in the groups receiving naloxone . Paco2 values also were better in these groups as compared to values in the placebo group . The steady-state plasma concentration of naloxone was 2.8–3.7 ng/ml during infusion at the rate of 5μg.kg−1 h−1 and 4.3–5.1 ng/ml during 10 μg · kg−1 h−1 naloxone infusion . The plasma clearance of naloxone was 30.5 and 35.4 ml . min−1 . kg−1 for the low and high dose groups , respectively , and showed a four-fold interindividual variation . The authors conclude that naloxone reverses epidural morphine analgesia in a dose-dependent manner . 
    Output:
    
There was a lack of evidence for any anti-pruritic efficacy with prophylactic propofol , epidural or intrathecal epinephrine , epidural clonidine , epidural prednisone , intravenous ondansetron , or intramuscular hydroxyzine .
CONCLUSION Naloxone , naltrexone , nalbuphine and droperidol are efficacious in the prevention of opioid-induced pruritus ; minimal effective doses remain unknown .
There is a lack of valid data on the efficacy of interventions for the treatment of established pruritus