Grandis 1992.

Methods	Single‐centre, randomised, double‐blind, placebo‐controlled study conducted in USA Grading of quality: Randomisation = C Blinding = A Intention‐to‐treat analysis =C Follow‐up = D Overall quality grading = C
Participants	198 adults and children aged 12 to 48 (mean 21.7) years undergoing tonsillectomy or adenotonsillectomy (indication not specified). Study and control groups were well matched with regard to age, sex and adenoidectomy (18 versus 14 respectively). Exclusion criteria: antibiotic administered within 1 week preoperatively, medical condition requiring perioperative antibiotic therapy, or allergy to antibiotic studied
Interventions	Ticarcillin + clavulanic acid, IV 3.1 g at completion of surgery, 6 and 12 hours after surgery; followed by amoxicillin + clavulanic acid 250 mg tds oral for 7 days
Outcomes	Primary outcomes: pain (scale of 1 to 10, 10 being most severe) and consumption of analgesics Secondary outcomes: fever (temperature > 99.9 °F) and return to regular diet (scale of 1 to 3; 1 = regular, 2 = soft, 3 = liquid) and activities (1 = normal, 2 = moderate, 3 = bed rest) Period of observation: 7 days
Notes	Anaesthetic and surgical techniques not mentioned as being controlled Follow‐up: only 101 (51%) patients (51 in antibiotic and 50 in control groups) completed follow‐up
Risk of bias
Bias	Authors' judgement	Support for judgement
Allocation concealment (selection bias)	Unclear risk	B ‐ Unclear