Nonsteroidal anti-inflammatory drugs for pain in women with endometriosis

Endometriosis is a common gynaecological condition that affects women and can lead to painful symptoms and infertility. It greatly affects women's quality of life, impacting on their careers, everyday activities, sexual and non-sexual relationships, and fertility. Non-steroidal anti-inflammatory drugs (NSAIDs) are the most commonly used first-line treatment for endometriosis.

To assess the effects of NSAIDs used for the management of pain in women with endometriosis compared to placebo, other NSAIDs, other pain management drugs, or no treatment.

We searched the Cochrane Menstrual Disorders and Subfertility Group Trials Register (April 2008) published in the Cochrane Central Register of Controlled Trials (CENTRAL) (The Cochrane Library), MEDLINE (1966 to April 2008), EMBASE (1980 to April 2008), and the reference lists from relevant publications. Experts in the field were also contacted for information about possible studies.

We included all randomized controlled trials (RCTs) describing the use of NSAIDs in the treatment of endometriosis in women of all ages.

Two review authors (CA and SH) independently read and extracted data from each of the included studies. Crossover trials were analysed using the inverse variance method in RevMan to calculate the odds ratio for binary outcomes.

Two trials were identified but only one trial, with 24 women, was included in the analysis. Comparing NSAIDs (naproxen) to placebo, there was no evidence of a positive effect on pain relief (odds ratio (OR) 3.27, 95% CI 0.61 to 17.69) in women with endometriosis. There was also inconclusive evidence to indicate whether women taking NSAIDs (naproxen) were less likely to require additional analgesia (OR 0.12, 95% CI 0.01 to 1.29) or to experience side effects (OR 0.46, 95% CI 0.09 to 2.47) when compared to placebo.

There is inconclusive evidence to show whether or not NSAIDs (naproxen) are effective in managing pain caused by endometriosis. There is no evidence on whether any individual NSAID is more effective than another. As shown in other Cochrane reviews, women using NSAIDs need to be aware of the possibility that these drugs may cause unintended effects.