Morphine postoperative nausea

Intravenous ondansetron (4 mg at induction of anesthesia and 0.13 mg with each 1 mg bolus of morphine) has been compared with intravenous droperidol (0.5 mg at induction and 0.05 mg with each bolus of morphine) in a double-blind trial in 142 patients (22). The two regimens had similar efficacy in the prevention of postoperative nausea and vomiting. The most important adverse effect was sedation significantly more patients given droperidol (15%) had excessive sedation than patients given ondansetron (5%). 

In a double-bhnd, randomized, uncontrolled study in 150 women to compare intrathecal morphine 100 micrograms plus ketoprofen, intrathecal morphine 200 micrograms, or epidural morphine 3 mg, postoperative nausea or vomiting occurred in 16,28, and 26% respectively (47). The incidence of itching was least in those given intrathecal morphine 100 micrograms. The results were unequivocal and did not justify preferring any one of the techniques as better or safer. 

Gastrointestinal Postoperative nausea due to morphine is associated with genetic variation at position 118 of the p opioid receptor. In 270 women who received intrathecal morphine 0.1 mg as postoperative analgesia, those who were homozygous for the A118G polymorphism had a higher incidence of nausea and vomiting [111 ]. 

Ondansetron In a randomized, double-blind study in 150 patients undergoing abdominal surgery with patient-controlled analgesia using morphine 1.5 mg, the combination of ondansetron 30 mg and prochlorperazine 20 mg reduced postoperative nausea and vomiting in the first 24 hours after surgery but not during the next 24 hours [130 J. 

Comparative studies In 14 patients using controlled-release oxycodone for postoperative pain and nine using patient-controlled morphine, there was a lower incidence of postoperative nausea and vomiting with oxycodone (14% versus 20%) [135 ]. There was no somnolence, respiratory depression, confusion, or pruritus in either group. 

This type of pain management is used for postoperative pain, labor pain, and cancer pain. The most serious adverse reaction associated with the administration of narcotics by the epidural route is respiratory depression. The patient may also experience sedation, confusion, nausea, pruritus, or urinary retention. Fentanyl is increasingly used as an alternative to morphine sulfate because patients experience fewer adverse reactions. 

Levorphanol (Levo-Dromoran) is an L-isomer morphi-nan derivative of morphine that is five to seven times more potent than morphine. It produces all of the side effects associated with morphine but less nausea. It is indicated for moderate to severe pain as a preoperative anxiolytic. It is often used in combination with thiopental to reduce the latter drug s anesthetic dose and to decrease postoperative recovery time. The o-isomer of levorphanol, dextrorphan, does not possess opioid analgesic activity but is a useful antitussive. 

Side-effects Morphine induces a variety of centrally- and peripherally-mediated side-effects. The most important of which is respiratory depression following parenteral administration, especially in the postoperative situation. Chronic oral application induces constipation and chronic treatment with oral morphine must be supplemented with laxatives. Other frequent side-effects are nausea, vomiting, dizziness and sedation. 

In a study of postoperative pain rehef, ketobemidone equalled morphine and pethidine with respect to efficacy of analgesia and adverse effects, such as shivering, nausea, and vomiting (SEDA-16, 81). 

Intrathecal morphine provides adequate postoperative analgesia in orthopedic surgery, but commonly causes urinary retention, pruritus, and nausea and vomiting. Finding the optimal dose of analgesic effect with minimal adverse effects is still the main objective of most papers published on morphine (49,50). 

Patient-controlled epidural fentanyl (20 micrograms with 10 minute lock-out) has been compared with patient-controlled intravenous morphine (1 mg with a 5-minute lock-out) in 48 women after cesarean section (93). Fentanyl was more efficacious in controlhng postoperative pain, with a lower incidence of nausea and drowsiness. 

A double-hlind, placebo-controlled study in 35 patients found that the preoperative use of fluoxetine 10 mg daily for 7 days reduced the analgesic effect of intravenous morphine given for postoperative dental pain. In contrast, a double-blind, crossover study in 15 healthy subjects found that a single 60-mg dose of fluoxetine slightly improved (by 3 to 8%) the analgesic effect (as assessed by dental electrical stimulation) of morphine sulfate in doses tailored to produce and maintain steady-state plasma levels of 15,30 and 60 nanograms/mL for 60 minutes. Plasma levels of morphine were not affected by fluoxetine, and morphine was found not to affect plasma levels of fluoxetine or norfluoxetine. The subjects experienced less nausea and drowsiness, but the psychomotor and respiratory depressant effects of morphine were not altered. ... 

Intrathecal morphine is often used in women undergoing cesarean delivery to enhance postoperative analgesia, but it is generally associated with significant adverse reactions, such as pruritus, nausea, and vomiting. A systematic review and meta-analysis of nine randomized controlled trials in 1152 patients has shown that the combination of morphine with serotonin receptor antagonists was associated with reduced severity of pruritus and a lower frequency of nausea and vomiting [133 ]. 

The optimal effective dose of epidural morphine for postoperative analgesia after cesarean section with minimal adverse reactions has been explored [143 ]. Epidural morphine provided better analgesia than parenteral opioids but increased the incidence of pruritus and nausea. 

Dahan A, van Dorp E, Sarton E. Postoperative morphine-6-glucuronide versus morphine equal analgesia but reduced nausea/vomiting. Anesthesiology 2007 107 A1744. 

Comparative studies An evaluation of the use of postoperative intravenous patient-controUed analgesia across a decade highlighted that this method of administration has become more popular and is associated with reduction in morphine consumption and respiratory depression however, there are significant risks of nausea (47%) and vomiting (19%) [100 ]. 

Epidural morphine 4 mg has been compared with epidural morphine 5 mg as patient-controlled analgesia for postoperative analgesia in women after cesarean section the latter had more nausea and vomiting (16% versus 72%) and more pruritus (29% versus 82%) [103 ]. 

Ketamine In 81 patients undergoing abdominal surgery, who were randomized to intraoperative and postoperative ketamine (0.5 mg/kg bolus - - 2 micrograms/kg/minute for 48 hours), intraoperative ketamine only (0.5 mg/kg bolus - - 2 micrograms/kg/ minute), or placebo, ketamine significantly reduced morphine requirements and the frequency of nausea [121 ]. 

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