acetaminophen ( paracetamol ) 20 mg/kg was administered orally to 45 gynecological outpatients who had received either alfentanil 5 micrograms/kg , fentanyl 1 microgram/kg , or no analgesic supplement immediately prior to the induction of general anesthesia .
C0002026
alfentanil
C0015846
fentanyl