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Drug–supplement interactions

By drug class: what happens, how serious it is, what to ask and what to do when counselling.

1. How an interaction arises: pharmacokinetic or pharmacodynamicFoundations · 4 min · free
2. CYP3A4 and P-glycoprotein: why some herbs change drug levelsCounselling · 5 min
3. Narrow therapeutic index drugs: where every interaction mattersCounselling · 5 min
4. How to check an interaction: sources, level of evidence and missing dataCounselling · 5 min
5. Medication history: the questions that uncover everything a patient takesFoundations · 4 min
6. Chelation: calcium, magnesium, iron, zinc and the spacing ruleCounselling · 5 min
7. How to communicate an interaction: with the patient and with the doctorCounselling · 4 min
8. Warfarin and supplements: what moves the INRAdvanced · 5 min
9. Direct oral anticoagulants: St John's wort and strong inducersAdvanced · 5 min
10. Antiplatelets and the supplements that may increase bleedingAdvanced · 5 min
11. Clopidogrel and its activation: where interactions can step inAdvanced · 5 min
12. High-dose vitamin E and the risk of bleedingCounselling · 5 min
13. Herbs and supplements before surgery: what to ask, when they stopCounselling · 5 min
14. NSAIDs: the kidneys, blood pressure and the supplements beside themAdvanced · 5 min
15. Statins and grapefruit: which ones are affected and which are notCounselling · 4 min
16. Statins and St John's wort: the loss of effect nobody feelsAdvanced · 4 min
17. Digoxin: St John's wort, liquorice, laxatives and calciumAdvanced · 5 min
18. Antihypertensives and what opposes them: liquorice, stimulants, saltCounselling · 5 min
19. Potassium alongside ACE inhibitors, sartans and spironolactoneCounselling · 4 min
20. Diuretics: magnesium, potassium, calcium and vitamin DCounselling · 5 min
21. Calcium channel blockers and antiarrhythmics: grapefruit and St John's wortAdvanced · 5 min
22. Metformin and vitamin B12: what to watch long termCounselling · 4 min
23. Antidiabetics and glucose-lowering supplements: cinnamon, berberine, chromiumAdvanced · 5 min
24. Alpha-lipoic acid, gymnema and insulin: the hypoglycemia you don't expectAdvanced · 5 min
25. GLP-1 analogues and SGLT2 inhibitors: weight-loss supplements and hydrationAdvanced · 6 min
26. Levothyroxine: calcium, iron, magnesium, coffee, soy and fiberCounselling · 5 min
27. Biotin and hormone tests: false results without any diseaseCounselling · 4 min
28. Corticosteroid therapy: calcium, vitamin D, licorice and potassiumAdvanced · 5 min
29. Serotonergic antidepressants: St John's wort, 5-HTP, tryptophan, SAMeAdvanced · 5 min
30. SSRIs and bleeding: when ginkgo and ω-3 matterAdvanced · 5 min
31. MAOIs: tyramine, tyrosine and stimulantsAdvanced · 6 min
32. Lithium: salt, coffee, herbal diuretics and fibreAdvanced · 5 min
33. Benzodiazepines and sleeping pills with valerian, kava, passionflower, melatoninCounselling · 5 min
34. Clozapine, olanzapine and CYP1A2: caffeine, smoking and fluvoxamineAdvanced · 5 min
35. Antiepileptics: folic acid, vitamin D, ginkgo and grapefruitAdvanced · 6 min