Positive - Negative Drug Herb Interactions

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.

3. Tannins

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.

4. Glycosides

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.

5. Blood-thinners

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.

10. Ginseng

Ginseng plus phenelzine sulfate may cause headache, tremulousness, and manic episodes. Ginseng should not be used with estrogens or corticosteroids.

11. Valerian

Valerian should not be combined with barbituates.

12. Kelp

Kelp as a source of iodine may interfere with thyroid replacement therapies.

13. Echinacea

Echinacea could cause liver toxicity and therefore should not be used with other known liver toxic drugs, such as anabolic steroids, amiodarone, methotrexate, and ketoconazole

14. Nonsteroidal anti-inflammatory drugs may negate the usefulness of feverfew in the treatment of migraine headaches

15. Kava when used with alprazolam has resulted in coma

16. Evening primrose oil and borage should not be used with anticonvulsants because they may lower the seizure threshold.

17. Both Rhubard and Aloe cause loss of potassium through the stool... this may increase the side effects of cardiac glycosides and antiarrhythmic drugs.

18. Astragalus (huang qi) may oppose immunosupressive drugs, because it tends to improve immune function.

Some of these herbs are not chinese herbs (feverfew, gingko, valerian, kava, echinacea, everning primrose, borage). If you saw a Chinese herbalist, they wouldn't be an issue. Plus, chinese herbalists prescribe more balanced formulas, not single herbs, so potential interactions with the single herbs are reduced.

Positive Drug Herb Interactions

1. Gan cao increases the effectiveness of prednisone. This benefit can be used to reduce the dosage of prednisone in patients who have to take it long term. This reduces the serious long-term side effects (bone density loss, adrenal insufficiency, etc.).
2. In typhoid fever, research showed that those given an herbal formula (xue yang mei) plus a sulfa drug did better than those just given the sulfa drug. Both groups had a 100% cure rate, but the combination group experienced few or no side effects.
   
3. In mastitis, those given a heat and toxin clearing herbal formula (jin yin hua, pu gong ying, yu jin, chi shao, dan shen, qing pi) plus penicillin/streptomycin injections did much better than those only given the injection.
4. In adult primary nephrotic syndrome, one group was simply given corticosteroids, while another group was also given an herb formulas (dan shen, di gu pi, gui ban, han lian cao, hong hua, nu zhen zi, gou qi zi, sheng di, zhi mu). The steroid only group had a recovery rate of 56%, while the combined group's recovery rate was 85%. In another study with nephritic patients, patients given predisone, zhi mu (anemarrhena), shu di huang (rehmannia), and gan cao (licorice) experienced less of the corticosteroid side effects.
   
5. Late-stage gastric cancer patients were studied. All patients were given a drug chemotherapy combo of either methotrexate, fluoroacil and vinblastine, or methotrexate, MFC, and fluorocil. One of the two groups was also given herbs (huang qi, tai zhi shen, caulis banthalobi, ji xue tang, bai zhu, fu ling, niu zhen zi, gou qi zi, tu su zi). Side effects were cut in half or eliminated in the chemo plus herbs group.