The drugs with both high potency and low side effects are preferred in the prevention of postoperative nausea and vomiting (PONV) which is a common problem. This prospective randomized study aimed to compare the efficacy of paracetamol on PONV in adults undergoing maxillofacial surgery.

One hundred-twenty patients are randomly divided into two groups; the paracetamol group who received the IV infusion of paracetamol (1.5 ml/kg); and the metoclopramide group who received the IV infusion of saline (1.5 mg/kg). The presence of vomiting and the actions indicative of nausea, such as repeated gagging or spitting, within 24h following general anesthesia are defined as PONV. All PONV episodes and postoperative pain scores are recorded during 24h postoperatively. The postoperative 0-4h and 4-24h are defined as early and late postoperative period, respectively. Intravenous 4 mg ondansetron as rescue antiemetic drug is administered in case of two or more vomiting episodes.

Inclusion Criteria:

• ASA (the classification of the American Society of Anesthesiologists) physical status I-II
• Patients who scheduled for elective maxillofacial surgery under general anesthesia

Exclusion Criteria:

• Patients with a history of allergy to any of the study medications (opioid, general anesthetic agents or paracetamol)
• History of opioid use, hepatic or renal disease, coronary, psychotic and neurologic diseases
• Use of antiemetic, antihistaminic, analgesic or corticosteroid 24 hours (h) prior to surgery