What do systematic reviews say?

Nifedipine vs placebo

It is very uncertain whether nifedipine changes good or excellent pain relief compared with placebo (very low certainty).

• Nifedipine for primary dysmenorrhoea 2021 · Cochrane Headline outcomes only
  OR 43.78 [5.34, 359.01]
  2 studies · 66 participants
  Very low