In vitro inhibitory effects of herbal supplements on tamoxifen and irinotecan metabolism

Abstract

Our data suggests that based on the measured IC50 values that skullcap and lemon balm could have potential negative clinical impact on the bioactivation of TAM but not likely with IR.

Potential risks associated with traditional herbal medicine use in cancer care: A study of Middle Eastern oncology health care professionals

“…A total of 29 of the 44 herbal products identified were associated with safety‐related concerns (65.9%) (Table ) . These were grouped according to 3 predominant themes: 1) potentially harmful herb‐drug interactions with a reduction in bioavailability (and thus efficacy) of anticancer agents, or increased drug levels with increased toxicity (15 herbs; 34.1%); 2) directly toxic effects of herbal compounds and metabolites (18 herbs; 40.9%); and 3) enhanced anticancer effects of conventional treatment through either synergy with herbal components or chemosensitization of cancer cells, thereby increasing the response to treatment (7 herbs; 15.9%).…”

“…[42][43][44][45][46][47] Additional effects on factors such as intestinal P-glycoprotein, which inhibits drug absorption, can alter the bioavailabil-ity of anticancer drugs such as etoposide. [48][49][50] The inhibition of boronic acid-based proteasome inhibitors (eg, bortezomib) 51 or the transport of irinotecan and its metabolite, SN-38, can increase biliary removal with an increase in the half-life of the drug 52 ; a reduction in organic anion transporting polypeptides can increase the absorption of chemotherapy agents such as etoposide, irinotecan, methotrexate, and paclitaxel 53 ; gingko biloba can inhibit paclitaxel metabolism (in vitro) 54 ; and an increase in the bioavailability or a decrease in the activity of tamoxifen in estrogen-responsive tumors may occur, [55][56][57][58] as well as a reduction in the drug's active metabolite levels via CYP2D6 inhibition. 59,60 Direct Herb-Related Toxicity…”