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February 2000
The effective dose of dexamethasone for antiemesis after major gynecological surgery.
Liu K, Hsu C-C, Chia Y-Y.
Anesth Analg. 1999;89:1316-8.
Commentary by Kathryn E. McGoldrick, M.D.
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[ see abstract below ]
Postoperative
nausea and vomiting is one of the most common and distressing side effects
after surgery performed under general anesthesia. Moreover, it is one of the
most frequent causes of delayed discharge and unanticipated hospital admission
following (planned) ambulatory surgery. Therefore, those of us who practice
in the ambulatory arena are always eager to improve our management of postoperative
nausea and vomiting.
The glucocorticoids, dexamethasone and methylprednisolone, exert antiemetic effects by an as-yet-undetermined mechanism. Although these drugs have been used for many years to prevent or attenuate chemotherapy related emesis, it is only in more recent years that they have been administered to reduce postoperative emesis. Various doses of dexamethasone (from 8 mg orally or 1 mg/kg up to 25 mg IV) have been effective in providing postoperative antiemesis. Indeed, the authors of the study under discussion previously demonstrated that 10 mg IV dexamethasone produced a significant reduction in the incidence of postoperative emesis [1]. The current randomized, double-blind, dose-ranging study was undertaken to determine the minimum effective dose of dexamethasone for postoperative antiemesis in 150 patients undergoing standardized general anesthesia for major inpatient gynecological surgery. Patients with a history of motion sickness, gastrointestinal disturbances, postoperative nausea and vomiting after general anesthesia, or who were menstruating or receiving hormonal therapy were excluded. Patients were randomly assigned to receive IV dexamethasone 10 mg, 5 mg, 2.5 mg, 1.25 mg, or placebo before the induction of general anesthesia. Patients
were assessed for incidence of vomiting at 4, 8, 12, and 24 hours after surgery. The results suggest that 2.5 mg is the minimum effective dose of dexamethasone for postoperative antiemesis in patients having general anesthesia for major gynecologic surgery. There were no discernible side effects from this therapy.
A few points are worth making here. First, this study did not address the important issue of postoperative nausea, a symptom almost as distressing as vomiting and often more resistant to prophylaxis and treatment. Second, the exclusion criteria eliminated many high-risk patients. Third, the authors assumed that the lack of difference in duration of hospital stay among the five groups implied that there were no additional wound infections or delayed healing accompanying dexamethasone administration. However, as the investigators themselves acknowledged, more detailed inspection with a longer duration of follow-up is necessary to conclusively prove these apparent findings. Finally, since dexamethasone is often used in combination with another antiemetic agent to enhance efficacy, future studies might well explore the minimum effective dose, as well as the optimal timing of administration, under circumstances of combination therapy.
References:
- Liu K, Hsu C-C, Chia Y-Y. Effect of dexamethasone on postoperative emesis and pain. Br J Anaesth. 1998;80:85-6.
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ABSTRACT
The effective dose of dexamethasone for antiemesis after major gynecological surgery.
AUTHORS: Liu K, Hsu CC, Chia YY.
SOURCE: Anesth Analg. 1999;89:1316-8.
ABSTRACT:
This double-blind, randomized, placebo-controlled study evaluated the minimum effective dose of dexamethasone for postoperative antiemesis. One-hundred fifty women scheduled for major gynecological surgery were randomly assigned to receive dexamethasone 10 mg (D10), 5 mg (D5), 2.5 mg (D2.5), 1.25 mg (D1.25), or placebo (P) before the induction of general anesthesia. A standardized general anesthesia technique was used. Postoperative pain was treated with bolus IV doses of morphine via a patient-controlled analgesia device. Patients were assessed for incidence of vomiting at 4, 8, 12, and 24 h after surgery. A total of 6, 6, 8, 15, and 19 patients in Groups D10, D5, D2.5, D1.25, and Group P experienced vomiting at least once within the first postoperative 24 h, respectively. Dexamethasone 10 mg, 5 mg, and 2.5 mg was more effective than dexamethasone 1.25 mg or placebo for antiemesis (P < 0.05). The difference in antiemetic effect among the 10 mg, 5 mg, and 2.5 mg groups was similar. The results suggest that 2.5 mg is the minimum effective dose of dexamethasone for postoperative antiemesis in patients undergoing general anesthesia for major gynecological surgery.
IMPLICATIONS: Although dexamethasone is effective for antiemesis, major side effects may accompany its perioperative use. To achieve the best antiemesis with the fewest side effects, dexamethasone 10 mg, 5 mg, 2.5 mg, and 1.25 mg were compared with placebo in surgical patients. We found 2.5 mg to be the minimum effective dose without discernible side effects.
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