Nagaoka 1980.

Methods	Double‐blind, head‐to‐head comparison, natural colds
Participants	222 adults, sex not reported for the subgroup of colds, 51 centres, outpatient departments of hospitals and clinics, URTI onset ≤ 2 days and fever ≤ 39 °C
Interventions	2 groups: fentiazac 300 mg/day and ibuprofen 600 mg/day for 3 days
Outcomes	Moderate to marked improvement of FGIR was more frequent in the fenoprofen group than the placebo (P value < 0.05)
Notes	No available data on adverse effects for the subgroup of common colds
Risk of bias
Bias	Authors' judgement	Support for judgement
Random sequence generation (selection bias)	Unclear risk	Comment: insufficient information about the sequence generation process
Allocation concealment (selection bias)	Low risk	"... randomisation process was done by two controllers and key codes were kept by controllers (in Japanese)"
Blinding (performance bias and detection bias) All outcomes	Low risk	"... double‐blind, double‐dummy method...active drug and placebo were quite similar in shape (in Japanese)" Comment: probably done
Incomplete outcome data (attrition bias) All outcomes	Low risk	"243 out of 244 patients were analyzed after the elimination of 1 drop‐out case" Comment: number of withdrawals was too small to make any important difference to the estimated intervention effect Comment: probably done
Selective reporting (reporting bias)	Unclear risk	No protocol, no convincing text
Other bias	Low risk	The study appears to be free of other sources of bias