Chinese Herbs With Diabetes, Blood Pressure and Heart Medicines

Check first, and keep taking your medicines

If you take medicine for diabetes, blood pressure, cholesterol, a heart condition or to thin the blood, talk to your prescriber and pharmacist before adding a Chinese herb or patent medicine. The NHS lists medicines for diabetes (such as metformin), high blood pressure (such as ramipril), statins and blood thinners (such as warfarin) among those that may not mix well with herbal medicines, and advises checking with a pharmacist first. [1] Do not stop any prescribed medicine without first talking to your doctor. [1]

Seek urgent help for chest pain, fainting, a very fast or irregular heartbeat, severe bleeding, or signs of very low blood sugar such as confusion. In the US call 911.

The main ways things go wrong

1. The herb itself changes how a medicine works (more bleeding, lower blood sugar, higher blood pressure).
2. The herb changes how a medicine is processed, so levels rise or fall.
3. A hidden drug is in the product. Products sold as Chinese herbal medicines have contained undeclared diabetes pills, diuretics and painkillers. [2] This is often the most dangerous route; see undeclared drugs in Chinese patent medicines.
4. A blood test gives a false result (digoxin; see below).

Diabetes medicines

• Evidence for herbs is limited. An umbrella review of herbal medicines for type 2 diabetes reported that ginger, turmeric and Jinlida granules (a Chinese patent formula) lowered HbA1c compared with placebo, but overall confidence was limited because the included reviews were of low to very low quality. [3] Label: promising but limited.
• Interaction data are missing. The same review said careful monitoring for hypoglycemia is essential when herbs are used with antidiabetic drugs, because data on herb-drug interactions are lacking. [3] In other words, a herb that lowers blood sugar could add to your medicine's effect.
• Ginseng. NCCIH notes some evidence that Asian ginseng might lower blood sugar and advises people with diabetes to consult their provider first. [4]
• Hidden drugs. In a Hong Kong series of 27 cases, 29 herbal antidiabetic products were adulterated, and the most common harm was hypoglycemia, followed by lactic acidosis. [5] If you also take diabetes medicine, this is a double-dose risk.

For what trials found on Chinese medicine in diabetes, see TCM for type 2 diabetes.

Blood pressure and heart medicines

• Licorice (gan cao). NCCIH says licorice contains glycyrrhizin, which can cause serious effects such as irregular heartbeat and cardiac arrest, especially in large amounts or long-term. It has been linked to severe effects in people who consume a lot of salt, have hypertension, or have heart or kidney conditions. [6] A review of cardiovascular drugs and herbs recorded low potassium (hypokalemia) after licorice with blood pressure medicines. [7] Related: licorice root tea.
• Ephedra (ma huang). Linked to high blood pressure, heart attack, seizure and stroke. It is banned in US dietary supplements. [8] See Ma Huang Tang and ephedra safety.
• Ginkgo with a thiazide diuretic. The same cardiovascular review recorded hypertension in a case where the two were used together. [7]
• Hidden diuretics. The FDA found furosemide, a prescription diuretic, in a Chinese product promoted for joint pain. [9]

Blood thinners (warfarin and similar)

Of cardiovascular drugs, warfarin was the one most often involved in reports, and the review concluded that people on anticoagulants are at the highest risk. [7]

• Danshen: three published cases of over-anticoagulation and bleeding with warfarin; the author concluded it should be avoided in people on warfarin. [10] See Danshen.
• Dong quai: may raise bleeding risk with warfarin or antiplatelet drugs. [11]
• Ginseng may interfere with clotting. [4]
• A 2021 review of Chinese medicines and warfarin said herbs may both strengthen and weaken warfarin's effect through several mechanisms, and that clinical use needs caution. [12]

Digoxin blood tests

Two Chinese medicines, Chan Su and Lu-Shen-Wan, cross-react with some digoxin blood tests (immunoassays). [13] In laboratory samples, they falsely raised readings on two tests and falsely lowered them on another. [13] A review also lists oleander-containing herbal preparations as interfering. [14] If you take digoxin, tell the clinician who orders your levels about every herbal product.

Evidence labels

See also: TCM for high blood pressure and cholesterol, interactions by drug class, Chinese herbal products: quality and interactions.