GNRH1 and endometriosis: Cheung et al. (2000) conducted a randomized, double-blind, crossover trial allocating participants with endometriosis to three doses of i.m. triptorelin 3.75 mg at 4-week intervals followed by three doses of i.m. leuprorelin 3.75 mg at the same time intervals (n = 27), or to the inverse sequence of the same two GnRH depot preparations (n = 21).