increase in testosterone levels in the body caused by
certain types of hormone therapy used to treat prostate
cancer. A testosterone flare may occur in patients who are
taking drugs called gonadotropin-releasing hormone (GnRH)
agonists. When first given, these drugs cause the testicles
to make more testosterone. This may cause symptoms, such as
bone pain and urinary problems, to get worse, but they
usually go away after the first few weeks of treatment.