Human Reproduction, Vol. 16, No. 8, 1719-1721,
August 2001
© 2001 European Society of Human Reproduction and Embryology
Randomized placebo controlled trial of lofexidine hydrochloride for chronic pelvic pain in women
1 Department of Obstetrics and Gynaecology, University of Southampton, Southampton and 2 Britannia Pharmaceuticals Limited, 41–51 Brighton Road, Redhill, UK
BACKGROUND: We hypothesised that the orally-active 
2-adrenoceptor agonist lofexidine hydrochloride would ameliorate chronic pelvic pain in women. METHODS: 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. RESULTS: 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. CONCLUSIONS: 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.
Key words: chronic pelvic pain/lofexidine hydrochloride/women
3 To whom correspondence should be addressed. E-mail: rws1{at}soton.ac.uk