Table 1: Potential benefits, dose forms available, and potential side effect/drug interaction data for CAMs used by prostate cancer patients as part of their treatment regimen (note that the potential drug interaction list does not include drugs which are used to treat prostate cancer, however, many of these drugs are used to treat co-morbidities that prostate cancer patients frequently experience and may therefore meaning these CAMs may indirectly interfere with their prostate cancer treatment). A drug interaction is defined as an interaction between the CAM and the drug which may either increase treatment-associated toxicity and/or decrease drug efficacy.
Name and proposed mechanisms of action (MOA) | Dose form(s) | Potential side effects | Potential drug interactions1 |
Green tea and green tea constituents (e.g. EGCG) Proposed MOAs include; anti-oxidant, inhibits PC cell proliferation and metastasis, promotes PC cell apoptosis |
Liquid (brewed tea, some energy drinks), powder, capsules, tablets | May cause acute liver injury, nausea, insomnia, and/or abdominal pain at EGCG doses of 30 - 90 mg/kg/day mg/kg per day [12,13] | Bortezomib and other proteasome inhibitors, dipyridamole, disulfiram, ephedrine, estrogens, fluconazole, fluvoxamine, hepatotoxic drugs, lithium, mexiletine, midazolam, MAOIs, nadolol, nicardipine, nicotine, pentobarbital, phenylpropanolamine, riluzole, stimulants, theophylline, verapamil, warfarin |
Modified citrus pectin (MCP) Proposed MOAs include; inhibits metastasis, promotes PC cell apoptosis |
Capsules, powder | May cause abdominal cramping and/or diarrhea at doses of > 14 g per day [18] | Oral medications, digoxin, lovastatin, tetracyclines |
Pomegranate fruit extract (PFE) Proposed MOAs include; anti-oxidant, inhibits PC cell proliferation, promotes PC cell apoptosis |
Capsules, powder | May cause diarrhea at doses of > 3 g per day [30] | Ace inhibitors, antihypertensives, carbamazepine, CYP 2D6 substrates, warfarin, rosuvastatin, tolbutamide |
Soy Proposed MOAs include; inhibits metastasis and PC cell proliferation, promotes PC cell apoptosis | Capsules, tablets, powder | No side effects observed in clinical trials (1 - 16 mg/kg per day) [66] | Antibiotics, antidiabetic, antihypertensives, CYP 2C9 substrates, diuretics, estrogens, levothyroxine, MAOIs, progestrones, tamoxifen, warfarin |
Selenium Proposed MOAs include; Anti-oxidant, improves immune system function, inhibits PC cell proliferation, promotes PC cell apoptosis |
Capsules, liquid concentrate | At high levels may cause GI disturbances, teeth decay, hair loss, neurological disturbances (2upper tolerable dose for adults is 400 ug per day) | Anticoagulants, antiplatelets, barbiturates, contraceptives, gold salts, statins, immunosuppressants, niacin, warfarin |
Saw palmetto Proposed MOAs include; inhibits PC cell proliferation |
Capsules and softgels | Minimal to no toxicity has been reported at doses as high as 960 mg per day [79] | Anticoagulants, antiplatelets, contraceptives, estrogens |
Vitamin D Proposed MOAs include; improves immune function, decreases inflammation, inhibits PC cell proliferation and metastasis |
Tablets, softgels |
Constipation, nausea, vomiting (2upper tolerable dose is 400 ug per day) |
Aluminum, atorvastatin, calcipotriene, cimetidine, CYP 3A4 substrates, digoxin, diltiazem, heparin LMWH, thiazides, verapamil |
Vitamin E Proposed MOA; anti-oxidant |
Capsules, tablets, liquid concentrate | May cause nausea and upset stomach (2upper tolerable dose is 1,000 mg per day) | Anticoagulants, antiplatelets, cyclosporine, CYP 3A4 substrates, statins, niacin, warfarin |
Lycopene Proposed MOA; anti-oxidant |
Capsules, tablets, liquid concentrate | May cause nausea, headache, diarrhea, and upset stomach at ~ 120 mg per day [54] | No known drug-drug interactions |
Sulforaphane Proposed MOA; histone deacetylase (HDAC) inhibitor, inhibits cell proliferation | Capsules | May cause bloating at 60 mg per day [94] | Clozapine, cyclobenzaprine, fluvoxamine, haloperidol, imipramine, mexiletine, olanzapine, pentazocine, propranolol, tacrine, theophylline, zileuton, zolmitriptan |
1data was obtained from https://naturalmedicines.therapeuticresearch.com;