Supplements vs prescription medicine — caution

### About this concern

Supplements and herbal capsules are often seen as harmless because they are "natural". The reality is that many of them are pharmacologically active and can interfere with prescription medicine — sometimes in dangerous ways. If you take any regular tablet for BP, diabetes, thyroid, cholesterol, blood thinning, depression, epilepsy, or any chronic condition, please read this page and then check with your doctor or pharmacist before adding any supplement.

### What we know

India has a vast OTC supplement and herbal market. Many brands you can buy at any pharmacy or online — Himalaya, Patanjali, Dabur, Zandu, Baidyanath, Organic India, plus a long tail of imported brands on Amazon and Flipkart. These products may have real effects on the liver enzymes that process medicine, on blood clotting, on blood pressure, on blood sugar, and on hormone levels. The result is that the same dose of your prescription tablet can suddenly become too strong or too weak.

### What to watch for

Common supplements and known interaction concerns:

• **St John's Wort** — speeds up liver enzymes and reduces the effect of many medicines, including antidepressants, oral contraceptives, BP drugs, blood thinners, and antiretrovirals. Avoid combining without medical advice.
• **Ginkgo biloba** — can increase bleeding risk, especially with aspirin, clopidogrel, warfarin, or other blood thinners.
• **Garlic extract capsules** — can thin the blood and increase bleeding; can also lower blood sugar.
• **Fish oil / omega-3 in high doses** — can increase bleeding risk with blood thinners.
• **Green tea extract capsules** (very different from drinking a cup of green tea) — can affect liver in high doses, interact with blood thinners, and reduce iron absorption.
• **Vitamin K** — directly counteracts warfarin and similar blood thinners. Sudden changes in leafy green intake also matter for these patients.
• **Calcium and magnesium** — can reduce absorption of thyroid tablets, antibiotics like ciprofloxacin and tetracyclines, and bisphosphonates. Take at least 4 hours apart.
• **Iron** — reduces absorption of thyroid tablets, certain antibiotics, and levodopa. Take separately and as advised.
• **Ginseng, ashwagandha** — can affect blood sugar, blood pressure, thyroid function, and sedatives. Care needed for chronic patients.
• **Turmeric capsules in high doses** — different from cooking turmeric; can thin blood.
• **Grapefruit and grapefruit juice** — not a supplement, but worth knowing — affects many prescription drugs.

### What you can do safely

• Maintain a single, up-to-date list of every tablet, capsule, drop, oil, and powder you take — including ayurvedic and homeopathic products. Show this list to every doctor you visit.
• Before buying any new supplement, ask the pharmacist or your doctor: "Is this safe with the medicines I already take?"
• Stagger doses where required — calcium, iron, and antacids should not be taken at the same time as thyroid tablets or many antibiotics.
• Tell your surgeon about every supplement at least 1-2 weeks before any planned surgery; many need to be stopped before procedures.
• For everyday wellness, prioritise food first — leafy greens, dals, fruits, curd, eggs, nuts in small portions — and treat supplements as a top-up, not a base.

### When to see a doctor

Please consult a doctor or pharmacist before starting any supplement if you are on prescription medication for a chronic condition, are pregnant or lactating, have liver or kidney disease, are scheduled for surgery, or are elderly with multiple medicines. Stop and seek care urgently if you notice unusual bruising, bleeding gums, dark stools, yellowing of eyes, sudden mood changes, palpitations, or unexplained tiredness after starting a new supplement.

### What we do NOT recommend over the counter

We do not sell or recommend any supplement as a substitute for prescribed medicine. We do not recommend stacking multiple herbal capsules from different brands. We do not recommend believing influencer claims about "natural" cures — natural does not mean safe with your medicine. Please ask your pharmacist before adding anything new.