C — Drugs

Beta-Blockers (Metoprolol/Atenolol) and Caffeine Caffeine (energy supplements) and Caffeine Caffeine (high-dose energy supplements) and Caffeine Calcium Channel Blockers (Amlodipine/Verapamil) and Caffeine Diuretics (Furosemide/Hydrochlorothiazide) and Caffeine Echinacea and Caffeine Ephedra/Ma Huang and Caffeine Phenylephrine (OTC energy blends) and Caffeine St. John's Wort and Caffeine

Vitamin C (High Dose ≥1000mg/day) and Calcitriol (Active Vitamin D)

Boron and Calcium carbonate Magnesium and Calcium carbonate Zinc and Calcium carbonate

Magnesium and Calcium citrate Zinc and Calcium citrate

Iron supplement and Calcium supplement Magnesium supplement and Calcium supplement Zinc supplement and Calcium supplement

Curcumin and Candesartan Ginkgo Biloba and Candesartan Milk Thistle and Candesartan St. John's Wort and Candesartan

Folic Acid and Capecitabine

CoQ10 (Ubiquinone) and Captopril Iron and Captopril Zinc and Captopril

Berberine and Carbamazepine Biotin and Carbamazepine Curcumin and Carbamazepine Echinacea and Carbamazepine Folate and Carbamazepine Garlic Extract and Carbamazepine Ginkgo Biloba and Carbamazepine Goldenseal and Carbamazepine Grapefruit and Carbamazepine Kava and Carbamazepine Milk Thistle and Carbamazepine NAC and Carbamazepine St. John's Wort and Carbamazepine Vitamin B12 and Carbamazepine Vitamin D and Carbamazepine

Grapefruit Juice and carbamazepine Niacinamide (Nicotinamide / Vitamin B3) and carbamazepine

Glutathione and Carboplatin

Berberine and Carvedilol Calcium and Carvedilol CoQ10 and Carvedilol Goldenseal and Carvedilol Magnesium and Carvedilol

Curcumin and Celecoxib Fish Oil and Celecoxib Ginkgo biloba and Celecoxib Milk Thistle and Celecoxib St. John's Wort and Celecoxib Turmeric and Celecoxib

Spirulina and Chlorella

Iron (oral supplements) and Chlorophyll Vitamin K (oral supplements) and Chlorophyll

Calcium and Chlorthalidone Potassium and Chlorthalidone

Garlic Extract and Chlorzoxazone Kava and Chlorzoxazone

TUDCA and Cholestyramine

Calcium Carbonate / Antacids and Chromium Insulin (exogenous) or Insulin Secretagogues (Sulfonylureas) and Chromium Metformin and Chromium

Calcium and Ciprofloxacin Dandelion Root and Ciprofloxacin Iron and Ciprofloxacin Lactobacillus acidophilus and Ciprofloxacin Magnesium and Ciprofloxacin Probiotics and Ciprofloxacin Psyllium Husk and Ciprofloxacin Zinc and Ciprofloxacin

Caffeine and ciprofloxacin Dairy Products and ciprofloxacin Multivitamins (with multivalent cations) and ciprofloxacin

Acetyl L-Carnitine and Cisplatin Echinacea and Cisplatin Glutathione and Cisplatin NAC (N-Acetylcysteine) and Cisplatin

Echinacea and Cisplatin (DDP)

St. John's Wort and citalopram Tryptophan and citalopram

Magnesium and Citalopram Melatonin and Citalopram Vitamin B12 (Methylcobalamin) and Citalopram

Antihypertensives (Multiple Classes) and Citrulline PDE5 Inhibitors (Sildenafil/Tadalafil) and Citrulline

Berberine and Clarithromycin Curcumin and Clarithromycin Echinacea and Clarithromycin Garlic Extract and Clarithromycin Ginkgo Biloba and Clarithromycin Goldenseal and Clarithromycin Grapefruit and Clarithromycin Kava and Clarithromycin Milk Thistle and Clarithromycin St. John's Wort and Clarithromycin

Bacillus coagulans and Clindamycin Probiotics and Clindamycin

Myo-Inositol and Clomiphene Citrate (Clomid)

Kava and Clonazepam Lemon Balm and Clonazepam Melatonin and Clonazepam Valerian and Clonazepam

Bilberry and Clopidogrel Bromelain and Clopidogrel EPA (Eicosapentaenoic Acid) and Clopidogrel Evening Primrose Oil and Clopidogrel Ginkgo biloba and Clopidogrel Quercetin and Clopidogrel Turmeric and Clopidogrel White Willow and Clopidogrel

Echinacea and Clozapine St. John's Wort and Clozapine

Caffeine and clozapine Tobacco (Smoking) and clozapine

Berberine and Codeine Curcumin and Codeine Echinacea and Codeine Garlic Extract and Codeine Ginkgo Biloba and Codeine Goldenseal and Codeine Grapefruit and Codeine Kava and Codeine Milk Thistle and Codeine St. John's Wort and Codeine

Iron and Colchicine Magnesium and Colchicine Vitamin C and Colchicine

Grapefruit Juice and colchicine

Calcium Carbonate and Collagen Peptides Vitamin D3 and Collagen Peptides Zinc Picolinate and Collagen Peptides

CoQ10 Ubiquinol and CoQ10 Ubiquinol

ACE Inhibitors (Lisinopril/Enalapril) and Creatine Nephrotoxic Antibiotics (Gentamicin/Tobramycin) and Creatine NSAIDs (Ibuprofen/Naproxen) and Creatine

EGCG Green Tea and Cyclophosphamide NAC (N-Acetylcysteine) and Cyclophosphamide Resveratrol and Cyclophosphamide

cranberry juice / cranberry supplements and cyclosporine saffron (Crocus sativus) and cyclosporine St. John's Wort and cyclosporine

Astaxanthin and Cyclosporine Berberine and Cyclosporine Calcium and Cyclosporine Curcumin and Cyclosporine Echinacea and Cyclosporine Ergothioneine and Cyclosporine Garlic Extract and Cyclosporine Ginkgo Biloba and Cyclosporine Goldenseal and Cyclosporine Kava and Cyclosporine Lactobacillus acidophilus and Cyclosporine Magnesium and Cyclosporine Milk Thistle and Cyclosporine Potassium and Cyclosporine Reishi (Ganoderma lucidum) and Cyclosporine TUDCA and Cyclosporine

St. John's Wort and CYP450-metabolized drugs (general)

Iron and Cytomel Selenium and Cytomel

melatonin and cytotoxic chemotherapy (general)