March 23, 2010 -- An experimental new drug may ease menstrual cramps by targeting the cause rather than the symptom of the pain.
Researchers say the drug, now in phase II clinical trials in the U.K. and U.S., works by blocking the hormone vasopressin, which is involved in contractions of the uterus. Increased levels of this hormone are believed to cause the pain associated with menstrual cramps.
Menstrual cramps, known in medical terms as dysmenorrhea, affect more than 50% of women of childbearing age. They occur when the smooth muscles of the uterus contract with increasing frequency. The most common symptoms are abdominal and back pain, but dysmenorrhea may also cause nausea, vomiting, sweating, and dizziness.
Treatments for dysmenorrhea include pain relievers, anti-inflammatory drugs, and contraceptives that stop menstruation. But researchers say these only relieve the symptoms of the condition rather than the underlying cause and may have unwanted side effects.
"We hope that the drug will provide a more effective treatment option for millions of women worldwide with this painful condition," researcher Andrzej R. Batt of Vantia Ltd., the U.K.-based pharmaceutical company that is developing and testing the drug, says in a news release. "Dysmenorrhea not only diminishes the quality of life for millions of women, but also has a hidden, society-wide economic cost that involves an enormous number of days lost from work and school."
Batt presented new information about the molecular structure of the drug, known as VA111913, today at the annual meeting of the American Chemical Society in San Francisco.
Last year, the drug passed the first stage of clinical trials by showing it was safe for further research in humans. The drug has been modified to allow it to be taken as a pill rather than as an injection.
Phase II clinical trials are under way at sites in the U.K. and the U.S., which are evaluating the drug’s effectiveness in women with dysmenorrhea.
Results of the phase II clinical trials are expected to be released later this year. If those results confirm the initial findings and phase III clinical trial findings are positive, the drug could be FDA approved and available for use in about four years.