Atef 2008.

Methods	Randomized, double‐blind, placebo‐controlled Medications administered at the end of surgery
Participants	Type of surgery: elective standard bipolar diathermy tonsillectomy Paracetamol group Entered/completing: 38/38 Age (mean, SD): 27 ± 4 Sex (male, %): 50 Placebo group Entered/completing: 38/38 Age (mean, SD): 25 ± 5 Sex (male, %): 47
Interventions	Intervention: paracetamol 1 g IV in 100 ml normal saline over 15 min Placebo: 100 ml normal saline
Outcomes	Pain intensity at rest and on swallowing (VAS 0 to 100) Pain relief (defined as a VAS score of < 30 mm at rest and < 50 mm on swallowing Opioid consumption (pethidine)
Source of funding	Not reported
Were treatment groups comparable at baseline?	Yes ‐ patient characteristics and duration of operation
Details of preoperative pain	Not reported
Notes	—
Risk of bias
Bias	Authors' judgement	Support for judgement
Random sequence generation (selection bias)	Low risk	Computer randomization
Allocation concealment (selection bias)	Unclear risk	Not described
Blinding (performance bias and detection bias) All outcomes	Low risk	Nurse not involved in the study prepared the study solutions. Similar appearance of the study infusions assured blinding.
Incomplete outcome data (attrition bias) All outcomes	Low risk	No dropouts; figures suggest that all participants reported data
Selective reporting (reporting bias)	Low risk	Primary outcome stated and fully reported. Stated secondary outcomes fully reported.
Size	High risk	Fewer than 50 participants per arm of the study (38 paracetamol, 38 placebo)