This is a multi-center, randomized, double-blind, double-dummy, placebo/active-controlled study. 200 subjects undergoing abdominal surgery under general anesthesia are planned to be enrolled and randomized into the HSK55718 group, morphine group, and placebo group.
Age ≥18 years old, regardless of gender;
18 kg/m2≤BMI≤30 kg/m2;
American Society of Anesthesiologists (ASA) gradeⅰ-ⅲ;
Accept abdominal surgery under general anesthesia;
A history of cardiovascular, respiratory, neurological, or psychiatric diseases that meet the protocol-defined exclusion criteria.
Clinically significant abnormalities in laboratory tests during the screening period.
A history of severe drug allergy or known allergy to the investigational drug.
Continuous use of opioid analgesics for more than 10 days for any reason within 3 months prior to randomization.