We previously reported that 20 and 40 microg/kg of
granisetron given during
anesthesia prevented
postoperative emesis with no severe complications. The aim of the current study was to determine the optimal dose of
granisetron for the prevention of
postoperative nausea and vomiting (
PONV) after
gynecological surgery. Two hundred female patients (ASA physical status I) were randomly allocated to one of five groups (n = 40 for each): saline (as a control),
granisetron 2 microg/kg,
granisetron 5 microg/kg,
granisetron 10 microg/kg, and
granisetron 20 microg/kg. Saline or
granisetron was given intravenously immediately after induction of
anesthesia.
PONV was assessed 24 h after surgery. The percentage of
emesis-free patients was significantly greater in the 5- to 20-microg/kg
granisetron groups than in the control and 2-microg/kg
granisetron groups (18%, 23%, 68%, 78%, and 75% of patients receiving saline or
granisetron 2 microg/kg, 5 microg/kg, 10 microg/kg, and 20 microg/kg, respectively).
Granisetron doses of 5 microg/kg or larger were also superior to the saline and 2-microg/kg
granisetron treatment for the prevention of
nausea over the 24-h study period (
nausea visual analog scales 24 h after surgery: 49, 41, 18, 16, and 14 mm in the control and
granisetron 2 microg/kg, 5 microg/kg, 10 microg/kg, and 20 microg/kg groups, respectively). A smaller proportion of patients received "rescue"
antiemetic in the 5-microg/kg or larger
granisetron groups than in the control and 2-microg/kg
granisetron groups (48%, 40%, 18%, 13%, and 10% of patients in the control and
granisetron 2 microg/kg, 5 microg/kg, 10 microg/kg, and 20 microg/kg groups, respectively). The
antiemetic effect of
granisetron was similar among the groups who received 5-microg/kg or larger doses. In conclusion, we suggest that the optimal dose of
granisetron is 5 microg/kg for the prevention of
PONV after
gynecological surgery.
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