Serious Side Effects of Nolvadex/Tamoxifen

Tamoxifen is given to most patients for 5 years after they are diagnosed with breast cancer to prevent the disease from returning. However; some develop resistance, which means their tumor is more likely to recur. According to this latest study, use of drugs like tamoxifen  in patients with low levels of another protein, E-cadherin, may promote more harmful cancer cell behavior. The E-cadherin protein makes cells stick together. In their experiments, researchers from Cardiff University found that when the protein was at reduced levels, the tamoxifen caused cancer cells to move around much more aggressively. This activity can lead to tumor growth.

After analyzing 9 prior studies, researchers have found that Tamoxifen use was associated with an 82% increase in clot-related stroke risk and a 29% risk for all strokes. The increase in risk translated into seven additional strokes among 1,000 patients taking the drug for 5 years.