John: Dysmenorrhoea, or period pain, is a common gynaecological problem and several Cochrane Review from the Cochrane Menstrual Disorders and Subfertility Group have examined the effects of a variety of interventions for this. An updated review from July 2015 examines the evidence for nonsteroidal anti-inflammatory drugs, and Cindy Farquhar one of the review’s authors and the Group’s Coordinating Editor from the University of Auckland in New Zealand tells us what they found.

Cindy: Dysmenorrhoea is when painful cramps occur at the time of menstruation and, when there is no underlying abnormality, it’s known as primary dysmenorrhoea and this is the focus for our review. Women with dysmenorrhoea have been found to have high levels of painful substances called prostaglandins. Prostaglandins are released from the lining of the uterus and cause cramping abdominal pain during the menstrual period. Nonsteroidal anti-inflammatory drugs acts by blocking an enzyme called cyclooxygenase, which is responsible for the formation of these prostaglandins.
We combined the evidence from all available randomised trials comparing anti-inflammatories versus placebo, paracetamol or each other, to determine their effectiveness and safety. This brought together data from 80 trials, with a total of 5820 women and twenty different types of anti-inflammatory. Overall, the quality of the evidence was rated as low for most comparisons, mainly because few of the trials reported their methods in sufficient detail. The evidence was also limited by the small sample size of most of the trials and the lack of studies comparing one type of anti-inflammatory versus another.
With these cautions in mind, we did find that anti-inflammatories appear to be much more effective than placebo. The evidence suggests that if about one in five women taking a placebo achieved moderate or excellent pain relief, this could be increased to two or three women in five with an anti-inflammatory. However, the anti-inflammatories were more likely to cause adverse effects such as indigestion, headaches and drowsiness. The trials suggest that if 10% of women taking placebo experienced side effects, this will rise to between 11% and 14% for women taking anti-inflammatories.
In the trials comparing anti-inflammatories with paracetamol, the anti-inflammatories appeared to be better than paracetamol but when compared against each other, it was unclear whether any anti-inflammatory was safer or more effective than the others. Two trials compared the more traditional anti-inflammatories (known as non-selective inhibitors) against a newer type (known as COX-2-specific inhibitors) and found no evidence that one type was more effective or tolerable than the other.
In conclusion, nonsteroidal anti-inflammatory drugs appear to be very effective for relieving period pain and seem to be more effective than paracetamol, but there is currently no indication than one type of anti-inflammatory is safer or more effective than any other.”

John: If you would like to explore these findings in more detail, they are available in full in the review in the Cochrane Library and you can find it by going to www dot Cochrane library dot com and searching for 'anti-inflammatory drugs and period pain'.