РефератыИностранный языкInInteractions Between Dietary Supplements And Pharmaceuticals Essay

Interactions Between Dietary Supplements And Pharmaceuticals Essay

, Research Paper





Interactions between dietary supplements and drugs will become a more serious


concern as supplement makers adopt better manufacturing practices. Some of these


interactions are positive to the patient?s health, while others are not. Mary Hardy,


M.D., is a member of the Integrative Medicine Department of Cedars-Sinai Medical


Center in Los Angeles. According to Dr. Hardy, ?Once these substances are properly


labeled, properly documented, and properly used by consumers, we can expect that


their most serious interactions are likely to involve pharmaceutical drugs.? Dr. Hardy


believes ?As pharmacists, you can look for the pharmacokinetic issues that will affect


the bioavailability or metabolism of the drug.? Also, pharmacodynamic interactions are


more individualized, less predictable, and more qualitative.


Herbs can counteract a drug?s therapeutic effect but, not all drug-herb


counteractions are negative. Two examples of positive drug-herb interactions are


seen with ginger and ginkgo biloba. Ginger is found to limit low-grade nausea related


to chemotherapy. Ginkgo biloba can be used to treat sexual dysfunctions that are


sometimes associated with the use of selective serotonin reuptake inhibitors (SSRIs).


Occasionally, herbs and drugs with entirely different mechanisms of action


reinforce each other. A study has shown that ginseng is known to be hypoglycemic.


Other high fiber hypoglycemic herbs can possibly reduce the absorption of


carbohydrates in the intestines. Dr. Hardy emphasizes that the blood sugar levels of


diabetic patients taking either type of herb and receiving insulin will need to be


monitored more closely.


According to studies, St. John?s Wort has been shown to decrease the


bioavailability of protease inhibitors. Protease inhibitors are the pharmaceuticals used


to treat AIDS patients. In one study, the trough level observed in sixteen healthy


patients declined 82% ? a level deep enough to allow for the emergence of resistant


viruses in patients with active AIDS. Dr. Hart emphasizes, ?This is a clinically


significant interaction, especially because St.John?s Wort has been shown in vitro to


be highly active against HIV. HIV patients are very likely to take it and to use high


doses.?


An article printed in the August 2000 issue of Pharmacy Practice News reports


that some herbs can change the level of drug absorption, either by increasing binding


or by precipitating the drug in the gut. For e

xample, hydrocoilldal fiber herbs such as


fenugreek, slippery elm, or even psyllium and bran can change absorption levels.


Dr. Hardy also points out the reality of ?double-dipping.? Herbs that share the same


active ingredients as a drug can enhance its therapeutic action. Combinations such as


ma huang and cold remedies containing pseudoephedrine, or foxglove and the


cardioglycoside digoxin are like ?double-dipping?.


Even if the herbs and drug do not contain the same active ingredients, doubling


can happen. A drug?s effect can be intensified if both the drug and the herb share the


same mechanism of action. If a patient is taking a barbiturate and adds valerian to the


diet, then the patient is reinforcing the drugs sedative effect. Some additive side


effects are seen between dietary supplements and drugs. If a patient is taking a


diuretic and depleting his or her potassium supply, licorice should not be consumed.


Licorice greatly increases potassium wastage. Kathryn L. Grant, Pharm D, Assistant


Professor of Pharmacy at the University of Arizona?s College of Pharmacy in Tucson


believes ?As we learn more about the pharmacodynamics and pharmacokinetics of


botanicals, we will more readily predict potential interactions.?


Some herbal therapies have normal but toxic reactions. The occurrence and


severity of these reactions depend on the dosage and preparation of the supplement.


This problem has been aggravated by the use of more concentrated preparations


based on distilled alcohol. Liver toxicities and carcinogenic properties have been


reported from this.


Adulterants have also been discovered in herbal products. Contaminants have


included diuretics, nonsteroidal anti-inflammatories (NSAIDS), benzodiazepines, and


heavy metals. In a documented case, a patient taking a protein supplement displayed


symptoms of lead poisoning. When analyzed, the supplement contained 2.88% lead.


?I believe there?s a lot to learn by taking a systematic look at case series and


cohort studies,? Dr. Hardy stresses. ?You have to know your manufacturer when you


buy these medications,? Dr. Hardy cautions. Direct research and adoption of better


manufacturing procedures are essential if pharmacists are to anticipate positive and


negative drug-herb interactions.


Gold Standard Multimedia. Clinical Pharmacology 2000. 1 November 2000


Kravetz, Shayna. ?Pharmacists Alerted to Alternative Agent Interactions With


Pharmaceutical Products?. Pharmacy Practice News August 2000: 16-17

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