Drug Interaction Report

Siltuximab may decrease the blood levels and effects of tamoxifen. You may need a dose adjustment if you have been receiving tamoxifen and are starting treatment with siltuximab. Likewise, if you have been receiving both medications, the dose of tamoxifen may need to be adjusted when siltuximab is discontinued. Contact your doctor if your condition changes or you experience increased side effects. It is important to tell your doctor about all other medications you use, including vitamins and herbs. Do not stop using any medications without first talking to your doctor.

Talk to your doctor before using tamoxifen with soy products. There is some evidence that substances present in soy may stimulate breast tumor growth and interfere with the action of tamoxifen, although this has not been proven. Whether soy products are effective for hot flashes is also uncertain. It is important to tell your doctor about all other medications you use, including vitamins and herbs. Do not stop using any medications without first talking to your doctor.