Herb-Drug Interactions


Herbs and natural therapies should be recommended before health conditions become so dire that pharmaceutical medications are prescribed considering all of the risks of serious side-effects. Unfortunately, traditional medicine such as Acupuncture, herbal therapy, and therapeutic essential oils are often the last resort of consideration for people with chronic conditions.

Once patients become disillusioned with contemporary medicine and its limitations they turn to what are called “alternative therapies”; by then it is often too late to turn the barge of chronic disease around. This is because chronic disease is much like a slow moving barge; it has progressed over a long period of time without startling affect. Incrementally small signs or symptoms begin to creep appear. No one symptom is alarming, but together they indicate that the inner microcosm of your body has imbalances. If the imbalances are not addressed early on, than disease develops. By the time one is diagnosed with high blood pressure, heart disease, or diabetes, the disease has been developing in your body for many years.

All of a sudden, like a bolt of lightning, your doctor gives you a dire diagnosis of a metabolic disease. It feels as though one day you were fine and the next day you have developed a serious condition. As you begin to research and search for options you find that conventional medicine mainly offers stop-gaps for chronic disease but no practical treatment strategies that will reverse the condition without going under the knife; the same holds true for pain syndromes. This is where Traditional Chinese medicine (TCM) differs dramatically; if caught in the early stages, it works to correct diseases at the core organ levels. Better yet, a good Chinese doctor can diagnose and reverse the imbalances in your body before the manifest in to a disease.

Understandably, patients want quick results, like taking a pill that eases all of your symptoms. As we are discovering, these quick fixes come with a price. Actual healing of the internal organs and bringing the body in to balance takes time; Chinese medicine says one month of treatment for each month of imbalance which again, have likely been accumulating over many years. This is why it is easier and takes less time to clear up less-chronic diseases using natural medicine as they are not just blocking the symptoms as pharmaceutical medications often do. To complicate matters, if your situation is so dire that you feel that your life depends on these medications then you may not be able to use herbs in your treatment strategy. Natural medicine is subtle; this is why there are few side-effects. By eliminating one major healing strategy such as herbal therapy, you are lessening your chances of a full recovery and a reversal of a disease process.

Few medicinal herbs have actually been studied exhaustively for possible interactions with pharmaceutical drugs. As a study published in the Excli Journal states, “There is limited information on the pharmacokinetics and pharmacodynamics of herbal supplements or herbal medicines per se.”  One exception is St. John’s Wort (Hypericum perforatum) (SJW) which may lower blood levels of methadone . SJW is a relatively common herb found in most health food stores throughout the U.S.A. The Excli study goes on to explain that SJW acts by the, “inhibition or induction of the metabolism of drugs catalyzed by the important enzymes, cytochrome P450 (CYP) in prescription drugs, which is especially concerning for drugs with a narrow therapeutic index”. 

“Cytochrome P450 (CYP) enzymes are common sites of drug interactions in human. Drugs may act as inhibitors or inducers of CYPs, leading to altered clearance of a second drug”, explains a study published in the Journal of the American Association of Pharmaceutical Scientists (AAPS) , which goes on to explain how St. John’s Wort may inhibit the therapeutic effects of a wide array of common medications including Anesthetic Drugs used in addicted patients. However, SJW possibly affect the metabolism of a wide array of drugs because of this including: 

  • Immunosuppressants 
  • Hormonal Therapy 
  • Anticoagulants 
  • Antihyperlipidemic Drugs 
  • Calcium Blockers 
  • Beta Adrenergic Blockers 
  • Antianginal Drugs Cardiac Inotropic Drugs 
  • Anti-HIV Drugs Anticancer Drugs 
  • Benzodiazepines 
  • Antidepressant Drugs 
  • Antiepileptic Drugs 
  • Central Muscle Relaxant Agents 
  • Drugs Acting on the Respiratory System 
  • Hypoglycemic Drugs 
  • Antimicrobics 
  • Antimigraine Drugs 
  • Drugs Acting on the Gastrointestinal Tract 

So, one can see that herbs do interact with medications, although there are very low incidents of reports of herb drug interactions compared to drug-to-drug interactions.

Most common types of drugs that interact with herbs:

  • Sympathomimic drugs
  • Cariovascular drugs
  • Diuretic drugs
  • Anti-diabetic drugs
  • Anti-coagulating drugs

Many herbs contain coumarins and those who are on blood-thinning medications should consult with a health care professional before using herbs. This is especially true with a classification of herbs known in Chinese medicine as “Blood Movers”. Typically herbs that move Blood are used to benefit the Heart and circulation; they are powerful healing tools. The problem arises when someone’s Heart imbalance has become so severe that they have been prescribed pharmaceutical medications. This is also true for some types of high blood pressure medications where blood thinning medications to lower blood pressure is common.

Common types of herb-drug interactions:

  • Improper absorption
  • Improper distribution
  • Improper metabolism of the liver
  • Improper elimination of the kidneys
  • Pharmacodynamic Interactions
  • Synergistic interactions
  • Antagonistic interactions

Speculation-Common Drugs and Possible Interactions with Chinese Herbs by TCM Classification

Exterior Releasing Herbs

In Chinese medicine we use a class of herbs referred to as exterior releasing herbs that are used to treat colds, flu and seasonal allergies. They are characterized by diaphoretic action, including perspiration. This is achieved by the herbal compounds stimulating sweat glands or by dilating peripheral blood vessels. While herbal diaphoretic activity is generally not associated with reported or potential herb-drug interactions, one could speculate that someone on diuretic medications could become dehydrated. Additionally, herbs that exert antibacterial and antiviral properties may potentiate the effects of antibiotics. Some exterior-releasing herbs promote diuresis, therefore, may make the effects of diuretic drugs stronger, leading to excessive loss of fluid and electrolytes.

Heat-Clearing Herbs

This class of herbs includes botanicals with antibiotic, anti-pyretic and anti-inflammatory properties as their primary pharmacological characteristics. Heat-clearing herbs in general are not known to interact adversely with drug therapies; however, the concurrent us of herbs and drugs with antibiotic effects may enable these substances to exert a synergistic effect, or potentiate the effects of one another. Some heat-clearing herbs also reduce blood pressure and should be used carefully monitoring for potential fluctuations of blood pressure.

Downward Draining Herbs

Herbs with laxative actions should be taken with adequate amounts of water and electrolytes, and should be used with caution in patients asking pharmaceutical laxatives and/or diuretics to avoid exaggerated diarrhea, dehydration, and electrolyte imbalance. Prolonged use of downward draining herbs may cause loss of potassium, leading to increased toxicity of cardiac glycosides.

Wind-Damp Dispelling Herbs

Herbs that dispel wind-damp are used for pain that is aggravated by wet conditions. They usually have analgesic and anti-inflammatory qualities. There is little or no documentation of any incidents of adverse interaction between analgesic and anti-inflammatory herbs and drug therapy. However, some herbs can mildly inhibit platelet aggregation, and should be taken with caution by patients who are taking anticoagulant or anti-platelet drugs.

Aromatic Damp-Dissolving Herbs

Aromatic and damp-resolving herbs may stimulate the digestive system to produce more stomach acid and increase peristalsis. Some aromatic herbs have anticoagulant properties and should be used with caution in patients using anticoagulant or anti-platelet drugs. 

Herbs that Regulate Water and Transform Dampness

These herbs often have diuretic effect eliminate the accumulation of excess water in the body. Combining diuretic herbs with diuretic drugs may lead to excessive loss of fluids and electrolytes.

Interior-Warming Herbs

Interior-warming herbs should be used with caution in patients having certain disorders such as heart arrhythmia, or who are on certain medications such as digoxin or thyroid supplements. Many herbs in this category stimulate the gastrointestinal system to increase production 
of gastric acid, therefore, may counter the effects of H-2 receptor antagonist (cimetidine, ranitidine or famotidine) or proton-pump inhibitors (omeprazole, or lansoprazole)

Qi-Regulating Herbs

Some Qi-regulating herbs stimulate the GI system increasing the production of gastric acid, interfering with anti-ulcer drugs. Herbs that move Qi may stimulate the sympathetic nervous system, therefore, 
should be used with caution in patients who take medications for high blood pressure, diabetes, hyperthyroidism, and seizures.Additionally, Qi-regulating herbs can stimulate the cardiovascular system and increase blood pressure, while others dilate the blood vessels to decrease blood pressure; therefore, they should be taken with caution in patients taking cardiovascular drugs.

Antiparasitic Herbs

These potent and toxic substances that expel parasites are generally used only if necessary, and only for a short period of time. Because of the infrequent use of these herbs, there are no known or documented herb-drug interactions. These drugs are toxic to both the parasite and the host (humans), therefore, should always be used with caution.

Stop-Bleeding Herbs

These herbs are generally used to only crisis situations to stop bleeding, and are to be discontinued when the bleeding stops. Therefore, should be used with caution with patient who has clotting disorders as the use of hemostatic herbs may increase the risk of clotting. They should be used with caution for patients taking anti-platelet or anticoagulant medications.

Blood-Invigorating and Stasis-Removing Herbs 

Herbs that dilate the blood vessels may potentiate the effects of anti-hypertensive drugs and cause hypotension. Herbs that treat blood stasis may enhance the actions of anti-platelet and anticoagulant 
medications, and prolong bleeding or increase bruising.

Phlegm-Resolving and Coughing /Wheezing Relieving Herbs

Herbs that transform phlegm, stop cough and relieve wheezing are used for their expectorant, antitussive and anti-asthmatic effects. Though these herbs are common and prescribed frequently, there are no reported or documented cases of her-drug interactions involving this group of herbs.

Shen-Calming Herbs

Herbs that calm the Shen (Spirit) have marked sedative and tranquilizing effects. Therefore, they should be used with caution when prescribed for a patient also taking other agent that may cause drowsiness.

Liver-Calming and Wind-Extinguishing Herbs

Herbs with ant-seizure and anti-epileptic action may have a sedative action and induce drowsiness. They should be used with caution by patients concurrently taking drugs that also have sedative properties. Herbs that treat the Liver of Chinese medicine often have a anti-hypertensive action may lower blood pressure (for those with abnormally high blood pressure only). To avoid inducing low blood pressure they should be used with caution by patients already taking anti-hypertensive medications.

Orifice-Opening Herbs

By the nature of disorders of sensory functioning, orifice-opening herbs are not used frequently or extensively. There is no reported or documented interaction between these herbs and pharmaceuticals.

Tonic Herbs

Many tonic herbs serve to enhance the immune system. Therefore they may interfere with immunosuppressants and increase the risk of organ rejection, or interfere with substances for regulation of immune functions such as chemotherapy. Tonic herbs that stimulate the endocrine system promote the release of hormones, and should be used with caution in patients who are already receiving hormone supplementation with insulin, steroids, and sex hormones. Some tonic herbs act on the cardiovascular system. Herbs with cardiotonic influence may increase blood pressure, while herbs with vasodilating effects may lower blood pressure. Therefore, any concurrent use of these herbs with cardiotonic pharmaceuticals must be carefully chosen and monitored to prevent adverse interactions.

Astringent Herbs

These herbs may block absorption of medications or nutrients as they have strong binding effects, and are commonly used to treat diarrhea and accidental ingestion of toxins and/or poisons.

Emetic Herbs

These herbs that are used to induce vomiting are extremely toxic, irritating, and potent. They should be used with extreme caution, according to appropriate guidelines, and only when necessary. 

This information has not been evaluated by the Food and Drug Administration. This information is not intended to diagnose, treat, cure, or prevent any disease.