The range of proven effective interventions for chronic pelvic pain remains limited and recommendations are based largely on single studies. Given the prevalence and healthcare costs associated with chronic pelvic pain in women, randomised controlled trials of other medical, surgical and psychological interventions are urgently required.Chronic pelvic pain is common in women in the reproductive and older age groups and it causes disability and distress that result in significant costs to health services. The pathogenesis of chronic pelvic pain is poorly understood. Often investigation by laparoscopy reveals no obvious cause for the pain. There are several possible explanations for chronic pelvic pain including undetected irritable bowel syndrome, and central sensitisation of the nervous system. A vascular hypothesis proposes that pain arises from dilated pelvic veins in which blood flow is markedly reduced. As the pathophysiology of chronic pelvic pain is not well understood, its treatment is often unsatisfactory and limited to symptom relief. Currently the main approaches to treatment include counselling or psychotherapy, attempts to provide reassurance using laparoscopy to exclude serious pathology, progestogen therapy such as with medroxyprogesterone acetate and surgery to interrupt nerve pathways.
Randomized placebo controlled trial of lofexidine hydrochloride for chronic pelvic pain in women.
We hypothesised that the orally-active alpha(2)-adrenoceptor agonist lofexidine hydrochloride would ameliorate chronic pelvic pain in women.
                A randomized placebo-controlled parallel group trial was undertaken in the University Hospital Gynaecology Clinic. Women with pelvic pain of at least 6 months duration were eligible, and were randomized using a sealed envelope system to receive up to 600 mg lofexidine hydrochloride twice daily over 8 weeks or placebo. Outcome measures were summary and daily diary visual analog scales for pain (VAS) and a 5 point self rating scale.
                9/19 women randomized to lofexidine completed the study compared to 14/20 of those randomized to placebo. Intention-to-treat analysis showed that 4/19 in the lofexidine group achieved 50% or greater reduction in VAS compared with 8/20 in the placebo group (OR 2.5, 95% CI 0.6--10.3). Summary and diary VAS were closely correlated.
                Within the limits of a small study with power to detect only a substantial effect, we conclude that lofexidine hydrochloride is not effective for the treatment of chronic pelvic pain.