Research into antagonism between antiemetics (droperidol, ondansetron, dexamethasone) and paracetamol in postoperative analgesia following thyroidectomies

INTERVENTION: Trade Name: DEXTROMETHORPHANE BROMHYDRATE (DEXTROCIDINE ®) Pharmaceutical Form: Syrup CAS Number: 125‐69‐9 Concentration unit: % (V/V) percent volume/volume Concentration type: equal Concentration number: 0,3‐ Trade Name: dropéridol (DROLEPTAN ®) Pharmaceutical Form: Solution for injection CAS Number: 548‐73‐2 Concentration unit: mg/ml milligram(s)/millilitre Concentration type: equal Concentration number: 2,5‐ Trade Name: ondansétron Pharmaceutical Form: Solution for injection CAS Number: 99614‐01‐4 Concentration unit: mg/ml milligram(s)/millilitre Concentration type: equal Concentration number: 4‐ Trade Name: phosphate sodique de dexamethasone MERCK Pharmaceutical Form: Solution for injection CAS Number: 2392‐39‐4 Concentration unit: mg/ml milligram(s)/millilitre Concentration type: equal Concentration number: 4‐ Trade Name: paracetamol ( PERFALGAN ®) Pharmaceutical Form: Solution for injection CAS Number: 103‐90‐2 Concentration unit: mg/ml milligram(s)/millilitre Concentration type: equal Concentration number: 10‐ CONDITION: PRIMARY OUTCOME: Main Objective: To evaluate the impact of substances administered for PONV prevention (doperidol, ondansetron, dexamethasone) on the analgesic efficacy of paracetamol after thyroidectomy. Primary endpoint(s): Measurement of the pain threshold using Painmatcher® in the recovery room: initial assessment upon arrival, then every 30 minutes for a total of 5 measurements. The area under the curve (AUC) constructed from these 5 measurements will be analyzed. Secondary objective: To evaluate the benefit of adapting postoperative analgesic management based on the substances used for PONV prevention; To assess the potential impact of CYP2D6 phenotypic variability on ondansetron-paracetamol interactions in clinical practice; INCLUSION CRITERIA: The study will be conducted in volunteer patients, male or female, aged 18 to 70 years, who have undergone total or partial thyroidectomy. Patients classified ASA I to III Patient with an Apfel score equal to 2. Informed consent signed by the patient Are the trial subjects under 18? no Number of subjects for this age range: F.1.2 Adults (18‐64 years) yes F.1.2.1 Number of subjects for this age range F.1.3 Elderly (>=65 years) yes F.1.3.1 Number of subjects for this age range