A prospective randomized double-blind study including patients ASA I-II, aged more than 18 years undergoing surgery under general anesthesia (GA) and endotracheal intubation. Patients were randomized allocated into 2 groups: ketamine group received ketamine gargle (0.5 mg/kg up to 30 ml dextrose water) and magnesium group received magnesium sulfate gargle (20 mg/kg up to 30 mL dextrose water ) 15 minutes before the operation.

Our primary outcome is sore throat and the secondary judging criteria are cough, dysphonia and satisfaction. A standardized anesthesia protocol was followed for all patients. After extubation, the patients were asked to grade POST, hoarseness, and cough at 15 min, 1h, and 24 h.

This is a prospective, single-center, randomized, double-blind study. the investigators included in the study the patients:

whose age is greater than or equal to 18 years; ASA class 1 or 2, proposed for elective visceral, orthopedic, oncology, ophthalmologic, urologic surgery under general anesthesia with orothracheal intubation, expected duration ≤ 120 min.

the non-inclusion criteria are known allergy to ketamine or maguisuim sulphate, ASA 3 and more, cervical surgery; rapid sequence induction, difficult intubation planned or history of difficult intubation, malformation of the O.R.L sphere; upper respiratory tract infections. the need for multiple laryngoscopies for orotracheal intubation (≥ 2 attempts); the need for a postoperative nasogastric tube.

randomization is performed upon entering the operating room. The gargle allocation scheme, Ketamine Group or Magnesium Sulfate Group was randomly generated using a randomization table with an allocation ratio of 1: 1.

Postoperative follow-up was carried out in the post-intervention monitoring room then in hospitalization within the various referring services (general surgery, orthopedics, O.R.L and ophthalmology).

On the day of the procedure, the doctor responsible for the study prepares the two types of solutions containing:

• One of magnesium sulfate (20mg / kg diluted in 30cc of 5% glucose serum);
• The other ketamine (50mg diluted in 30cc of 5% glucose serum). These two solutions were distributed over two groups of patients for use as a gargle, lasting at least 60 seconds for each patient in each group and 15 minutes before the surgery.

The primary endpoint is the incidence and severity of POST at the twenty-fourth hour postoperatively The secondary outcomes are the incidence and severity of POST at 15 minutes and one hour postoperatively; The occurrence of cough, The presence of dysphonia and Patient satisfaction

The severity of POST was scored on a three-point score from 0 to 2 (0 = No pain; 1 = Oropharyngeal pain on speaking; 2 = Spontaneous oropharyngeal pain)

Inclusion Criteria:

• age is greater than or equal to 18 years
• ASA class 1 or 2
• patients proposed for elective visceral, orthopedic, oncology, ophthalmologic, urologic surgery under general anesthesia with orothracheal intubation

Exclusion Criteria:

• known allergy to ketamine or maguisuim sulphate
• ASA 3 and more
• cervical surgery
• difficult intubation planned or history of difficult intubation
• malformation of the O.R.L sphere
• the need for multiple laryngoscopies for orotracheal intubation (≥ 2 attempts);
• the need for a postoperative nasogastric tube.