Ref (type)	Population	Outcome, Interventions	Results and statistical analysis	Effect size	Favours
Pain relief
Systematic review	599 women with moderate to severe pain 14 RCTs in this analysis	Proportion of women with pain relief 192/288 (67%) with NSAIDs (naproxen [7 RCTs], diclofenac [2 RCTs], indometacin, mefenamic acid, niflumic acid, nimesulide, and piroxicam [1 RCT each]) 61/311 (20%) with placebo	RR 3.43 95% CI 2.70 to 4.35	Moderate effect size	NSAIDs
RCT Crossover design 5-armed trial	104 women with primary dysmenorrhoea	Pain outcomes (TOTPAR scores at 8 and 12 hours, time to pain relief, and time to remedication) with ibuprofen arginate 200 mg with ibuprofen arginate 400 mg with ibuprofen 200 mg with ibuprofen 400 mg with placebo Absolute results not reported	The RCT reported significantly improved pain outcomes with ibuprofen arginate 200 mg or 400 mg and ibuprofen 400 mg compared with placebo, further details not reported P values not reported	Effect size not calculated	ibuprofen arginate 200 mg or 400 mg and ibuprofen 400 mg
RCT Crossover design 3-armed trial	73 women with moderate to severe primary dysmenorrhoea	Pain, assessed by TOPAR-8 score over 8 hours 20.0 with etoricoxib (120 mg, taken at the onset of painful menses) 12.6 with placebo (taken at the onset of painful menses)	P <0.001	Effect size not calculated	etoricoxib
RCT Crossover design 3-armed trial	73 women with moderate to severe primary dysmenorrhoea	Pain, assessed by TOPAR-8 score over 8 hours 21.5 with naproxen sodium (550 mg, taken at the onset of painful menses) 12.6 with placebo (taken at the onset of painful menses)	P <0.001	Effect size not calculated	naproxen sodium
RCT Crossover design 4-armed trial	144 women with moderate to severe primary dysmenorrhoea	Pain intensity, assessed by SPID-8 score over the first 8 hours 12.11 with naproxen (500 mg twice daily) 8.22 with placebo	P <0.001	Effect size not calculated	naproxen
RCT Crossover design 3-armed trial	149 women aged between 18 and 44 years, with primary dysmenorrhoea	Pain intensity, assessed by mean TOTPAR-8 scores over the first 8 hours 18.28 with celecoxib (400 mg, followed by 200 mg on day 1, then 200 mg twice daily as necessary on days 2 and 3) 12.82 with placebo	P <0.001	Effect size not calculated	celecoxib
RCT Crossover design 3-armed trial	149 women aged between 18 and 44 years, with primary dysmenorrhoea	Pain intensity, assessed by mean TOTPAR-8 scores over the first 8 hours 20.59 with naproxen sodium (550 mg twice daily on day 1, then 550 mg twice daily as necessary on days 2 and 3) 12.82 with placebo	P <0.001	Effect size not calculated	naproxen sodium
RCT Crossover design 3-armed trial	149 women aged between 18 and 44 years, with primary dysmenorrhoea	Pain intensity, assessed by mean SPID-8 values over the first 8 hours 10.06 with celecoxib (400 mg, followed by 200 mg on day 1, then 200 mg twice daily as necessary on days 2 and 3) 5.96 with placebo	P <0.001	Effect size not calculated	celecoxib
RCT Crossover design 3-armed trial	149 women aged between 18 and 44 years, with primary dysmenorrhoea	Pain intensity, assessed by mean SPID-8 values over the first 8 hours 11.48 with naproxen sodium (550 mg twice daily on day 1, then 550 mg twice daily as necessary on days 2 and 3) 5.96 with placebo	P <0.001	Effect size not calculated	naproxen sodium
RCT 3-armed trial	180 women with primary dysmenorrhoea	Pain scores, assessed by visual analogue scale [scale 0–10, higher scores indicating more severe pain] 2 months 3.6 with mefenamic acid 5 with placebo	P <0.01	Effect size not calculated	mefenamic acid
RCT 3-armed trial	180 women with primary dysmenorrhoea	Pain scores, assessed by visual analogue scale [scale 0–10, higher scores indicating more severe pain] 3 months 2.4 with mefenamic acid 6 with placebo	P <0.01	Effect size not calculated	mefenamic acid
RCT 3-armed trial	180 women with primary dysmenorrhoea	Pain duration 2 months 3 hours with mefenamic acid 16.2 hours with placebo	P <0.01	Effect size not calculated	mefenamic acid
RCT 3-armed trial	180 women with primary dysmenorrhoea	Pain duration 3 months 3 hours with mefenamic acid 15.4 hours with placebo	P <0.001	Effect size not calculated	mefenamic acid
Need for additional medication
Systematic review	667 women 10 RCTs in this analysis	Need for additional analgesia 104/390 (27%) with NSAIDs 150/277 (54%) with placebo	RR 0.57 95% CI 0.47 to 0.69 Analysis included data from 1 arm of an RCT (85 women; 4 treatment arms), which compared aspirin versus placebo	Small effect size	NSAIDs