Tamoxifen

A trial in men taking bicalutamide for prostate cancer found fewer breast events with tamoxifen. It does not establish that tamoxifen reliably treats every cause of gynecomastia or restores endocrine function after AAS use.^[1]

• Prevention of bicalutamide-associated events differs from established gynecomastia and post-AAS recovery.
• Abstract-checked; no qualified clinical review.

In breast-cancer patients, tamoxifen coadministration lowered anastrozole plasma concentration by 27%. The combination offered no efficacy advantage over tamoxifen in the ATAC trial; ARIMIDEX labeling advises against their coadministration.^[2]

• Postmenopausal breast-cancer population; no inference of a specific clinical outcome in men using these drugs after androgen exposure.
• Does not generalize to every SERM/aromatase-inhibitor pair.

Breast-cancer prevention trials found more thromboembolic events with individual SERMs including tamoxifen and raloxifene. Whether combining the two further increases that risk is unquantified.^[3]

• Trials in women; no dual-SERM trial and no evidence for a recovery regimen.

Testosterone-related hematocrit increases and tamoxifen/raloxifene thromboembolic findings come from different study populations. They motivate a possible overlapping concern, not evidence of a measured thrombosis increase from the selected pair.^[4][3]

• This evidence does not establish the magnitude or frequency of harm from the selected combination.