Negative drug-herb interactions (side effects as the result of taking drugs and herbs at the same time) have been over-hyped because of fear, lack of knowledge and sheer speculation. Although there are some negative interactions, research has also discovered positive interactions between drugs and herbal formulas.
Drug-drug interactions are a much more serious problem than either herb-drug or herb-herb interactions. This is because drugs are high doses of single, active, unstable chemicals, while herbs contain multiple ingredients, some of which are natural buffers.
Chinese herbal formulas are even more broad, comprehensive, and balanced than single western herbs. (When I talk about western herbs, I mean many of the single herbs you can buy in stores which are part of the western herbal tradition… and were not part of the chinese herbal tradition.)
Which is Safer – Single Herbs or Herb Formulas?
Herbal formulas are safer. The more singular a substance is, the more likely it is to cause side effects and interact with other substances. Studies bear this out- a number of them indicate that drugs negatively interact more with single herbs than they do with herbal formulas.
From most dangerous to safest (in order) are these cominations:
Type of Combination Situation and Results
1. Multiple drugs: The result of one or more physicians prescribing you one or more drug; interaction range from discomfort to life-threatening.
2. Drugs + single western herbs: 1 or more physician-prescribed drugs + you buy yourself 1 or more single herbs
3. One drug alone: Can still have mild to strong side effects
4. One herb alone: Mild side effects are possible
5. Multiple single western herbs: You buy several herbs for yourself and they may interact, especially if the combination is not based on tradition or research
6. Drug + herb formula: Prescribed by both a western and Chinese-style physicians; based on research and guesswork. The results of such studies have been positive. The appropriate formula is often able to balance out the drug’s side effects and/or boost its effectiveness
7. Single western herb + chinese herb formula: Again based partly on tradition and partly guesswork. Some unexpected interactions are possible but should be mild.
8. Personalized chinese herbal formula alone: Based on diagnosis, tradition, and research. There should be little or no unexpected interactions or side effects, and if there are, the physician can modify the formula to better suit you.
Our current habit of purchasing single herbs like ginseng and gingko (amateur self-prescription) is more dangerous than seeing an acupuncturist for a personalized chinese herbal formula. Did you know that at least 6 million people in the U.S. take ginseng singly? (Read more on ginseng) Also read number 10 in the next section…
In addition, when you take several drugs and several single herbs, there are many more potential interactions… that real-world situation is more complex than any of our research has investigated. So, it’s a good rule of thumb to take as few drugs and single herbs as possible.
The safest therapy options are just about the reverse order of the list above.
These are not hard and fast rules. In some situations, multiple drug therapy is the best choice… I urge you to review your options with your western and chinese-style physicians, and together you can all make the best decision.
Negative Drug Herb Interactions
1. Pain Medications
Sometimes herbs and acupuncture can neutralize the effect of pain drugs. For example, patients on neurontin or morphine need to be treated differently. Acupuncture in these patients should be of shorter duration with less stimulation and subtler point selections (like eight extra points, e.g.). Moxibustion is a helpful alternative.
2. Chinese Licorice
Gan cao (chinese licorice) is sometimes problematic… it is in many herb formulas, but in low dosages. Higher dosages can lead to fluid retention. Gan cao can also reduce the absorption of oral tetracycline and some other meds, and can offset the pharmacological effect of spironolactone. The rule of separating the dosage times of herbs and drugs solves this problem.
Tannins are insoluble with antibiotics. A few herbs such as Da Huang (rhubarb), He Zi, and Mo Yao (Myrrh) contain tannins. Tannic acids may inhibit the absorption of iron.
Glycosides, which are active ingredients in many herbs, are neutralized by acidic drugs. That means that, for example, Vitamin C (ascorbic acid) and nicotinic acid could prevent your herbs from working.
Patients on warfarin (coumadin) are most at risk for problems from drug-herb interactions. Warfarin is given to thin the blood, thus preventing the likelihood of clots blocking blood vessels in the heart, lungs, or brain. Warfarin’s dosage needs to be quite exact to work, so we don’t want any herbs affecting it. Herbs and herbal formulas that contain blood movers must be avoided. This includes, among others, herbs dan shen (salvia), dang gui (angelica), and yan hu suo (corydalis), and herb formulas like xue fu zhu yu tang, di dan tang, and tao he cheng qi tang. Feverfew, garlic, Ginkgo, ginger, and ginseng may alter bleeding time, and so they also should be avoided by patients on warfarin.
6. Dan Shen (Salvia)
Salvia (see #5) can also reduce the effectiveness of anti-ulcer drugs.
7. Surgery and Herbs
It’s a good idea to stop taking herbs 5 days before surgery, and then after surgery take herbs only to rebuild the body.
8. Drugs for the Heart
Ma Huang (ephedra) should not be taken (even in an herbal formula) if your are on digitalis or any other heart drugs. It also reduces the effectiveness of anti-anxiety and sedative drugs, and increases the cardiovascular effects of caffeine. Kyushin, gan cao (licorice), plantain, uzara root, shan zha (hawthorn), and ren shen (ginseng) may interfere with digoxin.
9. St. John’s Wort
Studies have shown that patients who take St. John’s Wort while on a Selective Serotonin Re-uptake Inhibiting (SSRI) anti-depressant end up with varying blood levels of drugs. This means it interferes with the effectiveness of your anti-depressant. Because its mode of action is not understood, it should be avoided with monoamine oxidase inhibitors and SSRI’s.
It also appears to reduce blood levels of cyclosporin, a drug taken to prevent the body’s rejection of transplanted organs. And it reduces the effectiveness of the AIDS drug indinavir. It’s not yet clear whether it interferes with the metabolism of all drugs, or just some. It may be difficult for your medications to work effectively if you take St. John’s Wort.
Ginseng plus phenelzine sulfate may cause headache, tremulousness, and manic episodes. Ginseng should not be used with estrogens or corticosteroids.
Continued in Part 2!