Table 2.
Studies reporting drug–NP interactions of no clinical importance
| Herbal product; formulation (dosage) | Anti-cancer agent (dosage) | Study population characteristics (n) duration | Outcome | Reference |
|---|---|---|---|---|
| Grapefruit juice (200 mL 3 times daily) | Sunitinib (20–25 mg daily) | Renal cancer or gastrointestinal stromal tumour (n = 8) | Increased bioavailability of sunitinib, non-clinically relevant | Van Erp et al. 2011 [88] |
| Curcumin phosphatidylcholine complex (1–4 g daily) | Irinotecan (200 mg/m2on day 1 and 15 of 28 day-cycle) | Advanced solid tumours | No significant changes in plasma exposure and other pharmacokinetic properties of irinotecan and its metabolites | Gbolahan OB et al. 2022 [89] |
| Green tea; capsule containing 150 mg EGCG equivalent to 5–6 cups of regular green tea (1000 mg twice daily) | Tamoxifen (20 or 40 mg daily) | Women with breast cancer (n = 14); 14 days | Tamoxifen and endoxifen pharmacokinetics were not affected by green tea supplements | Braal et al. 2020 [90] |
| Garlic; tablet containing 3600 µg (600 mg twice daily) | Docetaxel (30 mg/m2 weekly) | Women with breast cancer (n = 10); 12 days between day 5 to 17 | Garlic supplementation did not significantly affect the disposition of the CYP3A4 substrate drug docetaxel. However, it could not be excluded that garlic decreases the clearance of docetaxel in patients with CYP3A5*1/*1 allele | Cox et al. 2006 [34] |
| Medicinal cannabis; 1 g/L herbal tea containing 18% THC and 0.8% CBD (once daily) | Irinotecan (90 min IV infusion 600 mg) or docetaxel (1-h IV infusion, at a fixed dose of 180 mg) | Cancer patients being treated with irinotecan (n = 12) or docetaxel (n = 12); 15 days | Co-administration of medicinal cannabis herbal tea in cancer patients treated with irinotecan or docetaxel did not significantly influence plasma pharmacokinetics of these drugs | Engels et al. 2007 [91] |
| Echinacea purpurea; extract drops containing 95% aerial parts and 5% roots (20 drops three times daily) | Docetaxel (135 mg IV infusion every 3 weeks) | Cancer patients (n = 10); 14 days between docetaxel cycle | At the recommended dose and schedule of a commercially available E. purpurea extract had no statistically significant interference with docetaxel pharmacokinetics | Goey et al. 2013 [92] |
| Soy food and soy products | Tamoxifen | Patients with breast cancer | No evidence supporting the use of soy food products would detrimentally affect pharmacological activity of tamoxifen | Guha et al. 2009 [93] |
| European mistletoe (Viscum album) extract (20–250 mg daily by subcutaneous injection) | Gemcitabine (750 mg/m2 intravenously) on day 1 and 8 of a 3-week cycle | Patients with advanced solid tumours (n = 20) | Systemic exposure to gemcitabine was not significantly affected by co-administration with mistletoe extract | Mansky et al. 2013 [94] |
| Chrysin; (250 mg twice daily) | Irinotecan (IV 350 mg/m2 every 3 weeks) | Patients with metastatic colorectal cancer (n = 20); 1 week | Combining chrysin with irinotecan may be a safe and potentially useful means of preventing diarrhoea | Tobin et al. 2005 [95] |
| Fucoidan (sulphated carbohydrates derived from marine brown algae, Undaria pinnatifida; 500 mg twice daily for a 3-week period) | Letrozole (2.5 mg daily) and tamoxifen (20 mg daily) for at least 4 weeks | Women with breast cancer being treated with either letrozole or tamoxifen (n = 10 each) | Plasma trough concentrations of letrozole, tamoxifen and its metabolite, endoxifen appeared to be unaffected by the concurrent use of fucoidan. The combination was well tolerated with no adverse effect related to the use of the natural product was reported | Tocaciu et al. 2018 [96] |
| Milk thistle; seed extract containing 80% silymarin (three times daily) | Irinotecan (125 mg/m2 IV infusion once a week) | Cancer patients (n = 6); milk thistle was taken for 4 days before the second irinotecan dose and continued for 14 days | Milk thistle possessed little risk of interfering with pharmacokinetics of chemotherapeutic agents that are substrates of CYP3A4 and UGT1A1 | Van Erp et al. 2005 [97] |
| Ginkgo biloba; EGb 761 (120 mg twice daily) | Tamoxifen; anastrozole; letrozole | Women living with early stage breast cancer tamoxifen(n = 20) anastrozole (n = 20) letrozole (n = 20); 3 weeks | Co-administration of EGb761 was unlikely to lead to clinically significant interaction for women who are receiving hormonal treatment for breast cancer | Vardy et al. 2013 [98] |
| Green tea extract (contained 60% EGCG; 500 mg twice daily for 7 days) | Nintedanib (100–150 mg per oral twice daily) | Patients with pulmonary fibrosis (n = 28) | Co-administration of green tea extract led to a modest yet significant reduction (with a median of − 21%) in systemic exposure to nintedanib. However, this might be of little clinical importance given that the range of therapeutic concentration of the drug is likely to be wide | Veerman et al. 2022 [99] |
CBD cannabidiol, EGCG epigallocatechin-3-gallate, IV intravenous, THC delta-9-tetrahydrocannabinol