Summary of findings 1. Nifedipine compared to placebo for primary dysmenorrhoea.
| Nifedipine compared to placebo for primary dysmenorrhoea | ||||||
| Patient or population: primary dysmenorrhoea Setting: outpatient clinic Intervention: nifedipine Comparison: placebo | ||||||
| Outcomes | Anticipated absolute effects* (95% CI) | Relative effect (95% CI) | № of participants (studies) | Certainty of the evidence (GRADE) | Comments | |
| Risk with placebo | Risk with nifedipine | |||||
| Pain relief (any) | 400 per 1,000 | 858 per 1,000 (635 to 954) | OR 9.04 (2.61 to 31.31) | 66 (2 RCTs) | ⊕⊝⊝⊝ VERY LOW 1,2 | |
| Good or excellent pain relief | 0 per 1,000 | 0 per 1,000 (0 to 0) | OR 43.78 (5.34 to 359.01) | 66 (2 RCTs) | ⊕⊝⊝⊝ VERY LOW 1,2 | |
| Health‐related quality of life | Not reported in any study | |||||
| Total adverse effects | 800 per 1,000 | 790 per 1,000 (242 to 978) | OR 0.94 (0.08 to 10.90) | 24 (1 RCT) | ⊕⊝⊝⊝ VERY LOW 2,3 | |
| Bothersome adverse effects | 400 per 1,000 | 265 per 1,000 (45 to 737) | OR 0.54 (0.07 to 4.20) | 24 (1 RCT) | ⊕⊝⊝⊝ VERY LOW 2,3 | |
| Requirement for additional medication | 800 per 1,000 | 219 per 1,000 (74 to 561) | OR 0.07 (0.02 to 0.32) | 42 (1 RCT) | ⊕⊝⊝⊝ VERY LOW 2, 4 | |
| *The risk in the intervention group (and its 95% confidence interval) is based on the assumed risk in the comparison group and the relative effect of the intervention (and its 95% CI). CI: Confidence interval; RR: Risk ratio; OR: Odds ratio; | ||||||
| GRADE Working Group grades of evidence High certainty: We are very confident that the true effect lies close to that of the estimate of the effect Moderate certainty: We are moderately confident in the effect estimate: The true effect is likely to be close to the estimate of the effect, but there is a possibility that it is substantially different Low certainty: Our confidence in the effect estimate is limited: The true effect may be substantially different from the estimate of the effect Very low certainty: We have very little confidence in the effect estimate: The true effect is likely to be substantially different from the estimate of effect | ||||||
1Downgraded 2 levels for imprecision; data from two small trials and thus likely underpowered to make reliable conclusions about outcomes 2Downgraded 1 level for serious risk of bias; very uneven allocation to intervention and control groups in one trial 3Downgraded 2 levels for imprecision; data only from one small trial and thus likely underpowered to make reliable conclusions about outcome 4Downgraded 1 level for serious risk of bias; unexplained high attrition (8/50 participants)