Painkillers take about 20-30 minutes to be effective. Painkillers such as ibuprofen, celecoxib, tramadol, etc., which have a relatively weak analgesic effect, can be used to treat pain after surgery when there is pain in the abdominal incision, or pain in the drainage tube. Oral painkillers are absorbed in the stomach, and the painkillers enter the bloodstream in 20-30 minutes and last for about 6 hours. If the patient experiences abdominal pain again after 6 hours, the medication may be given again. If oral medication does not stop the patient’s pain, other pain medications may be given by intramuscular injection or intravenous drip.