Goserelin (Zoladex)

Safety Summary

The adverse effect profile is primarily driven by the expected consequences of gonadal steroid deprivation. In men with prostate cancer, hot flashes (62%), sexual dysfunction (21%), and decreased erections (18%) are most common (FDA label, n=242). In women treated for breast cancer, hot flashes occurred in 70-76% and decreased libido in 47.7% (FDA label). For endometriosis, hot flushes (96%), vaginitis (75%), headache (75%), emotional lability (60%), and depression (54%) were reported (FDA label, n=411). Bone mineral density decreases by approximately 4.3% at the vertebral spine after 6 months of treatment in women, with partial recovery (to 2.4-2.5% loss vs baseline) 6-12 months post-treatment (FDA label). HRT add-back can mitigate bone loss without compromising efficacy (FDA label). Injection site vascular injury has been reported, including hemorrhagic shock requiring transfusion (FDA label). The 16-gauge needle of the standard implant causes more discomfort than typical injections; a reformulated microsphere version (LY01005) using a 21-gauge needle showed 0% injection-site reactions vs 1.4% for the standard implant (PMID 37010251, PMID 36895949). Cardiovascular safety data from the ISACS registry showed no significant left ventricular dysfunction after one year of goserelin plus tamoxifen PMID 39860490. Long-term use in men is associated with increased risks of diabetes and cardiovascular disease including MI, sudden cardiac death, and stroke (FDA label).