Uses of this Herb
Allergic Rhinitis
Asthma
Common Cold
Cough
Influenza
Sinusitis
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Look Up > Herbs > Ephedra
Ephedra
  Ephedra (English)
Ephedra sinensis (Botanical)
Ephedraceae (Plant Family)
Overview
Macro Description
Part Used/Pharmaceutical Designations
Constituents/Composition
Commercial Preparations
Medicinal Uses/Indications
Pharmacology
Dosage Ranges and Duration of Administration
Side Effects/Toxicology
Warnings/Contraindications/Precautions
Interactions
Regulatory and Compendial Status
References


Overview

Native to central Asia, Ephedra sinensis (also called ma huang) has been used in Traditional Chinese Medicine for more than 5,000 years. It is primarily a remedy for bronchial asthma but also prescribed for symptoms of cold and flu, including fever, chills, cough wheezing, headache, and nasal congestion. It is the most widely used herbal medicine with known efficacy in the treatment of bronchial asthma.

While several species of ephedra are distributed throughout the world, Ephedra sinica, or Chinese ephedra, is particularly potent in alleviating asthmatic symptoms. Pharmacological studies show that ephedra and ephedrine, the main active constituent of ephedra, is a central nervous system stimulant. This compound induces bronchodilation and vasoconstriction, and it decreases bronchial edema. Ephedra is also sold commercially as a weight-loss aid, although the evidence for its effectiveness in treating obesity is contradictory.

Adverse side effects such as elevated blood pressure and heart rate are associated with ephedra. In addition, ephedrine can be used as a precursor for synthesizing methamphetamine, an illegal drug. These potential risks associated with the sale and use of ephedra have prompted some states in the United States to pass laws regulating the sale of the herb and preparations derived from it. In reality, however, experts agree that the vast majority of ephedrine products currently available are not derived from ephedra, but instead are chemically synthesized from L,1-phenyl-1-acetylcarbinol and methylamine.

Since the 1980s, ephedra has been the center of major controversy between the nutritional supplement industry and the U.S. Food and Drug Administration (FDA). Concerns have been raised over the use of this herb as a weight-loss agent, central nervous system stimulant, athletic performance enhancer, and substitute for illegal "street" drugs. In response to these concerns, the American Herbal Products Association in 1994 disseminated a warning label for consumers about the adverse side effects of ephedra. Following the lead of the FDA, the herb industry specified standards for ephedra products. These standards call for a limit on the intake of ephedra preparations of 25 mg total alkaloids per dose and a total daily consumption of 100 mg of ephedra.

In 1997, the FDA issued further regulations governing the formulations of ephedra products. However, other agencies have challenged the foundation of the FDA's recommendations. While the U.S. General Accounting Office (GAO) conceded that the FDA was justified in evaluating the safety of ephedra products, the GAO also questioned the cost-benefit analysis used by the FDA to guide its decision.

Earlier research revealed that caffeine and aspirin, either separately or in combination, potentiated the appetite-suppressant, thermogenic (heat-promoting), and athletic-enhancing effects of ephedra. More recent findings, however, indicate that this herb, when administered singly and devoid of either caffeine or aspirin, is safe for individuals with normal blood pressure.


Macro Description

Ephedra is a genus of dioecious, perennial evergreens. These erect, highly branching subshrubs can reach a height of four feet. Virtually leafless, ephedra is typically found on tundra as well as rocky and sandy slopes. It is distinguished by its cylindrical, slender, yellow-green branches and under-runners. Its prostate stems have vertical grooves and are gray-green to pale green in color.

The small, reddish-brown leaves that radiate from the nodes are toothed at the tips, sometimes forming pointed scales. The yellowish-green flowers are so small and inconspicuous that they appear in terminal catkins as acurninate scales. Male and female flowers bloom separately. In August, the female flowers bear poisonous, fleshy red cones resembling berries. These are known as ephedra, or seagrapes.


Part Used/Pharmaceutical Designations

Young stems, branchlets


Constituents/Composition

2-aminophenylpropane-type alkaloids, primarily L-(-)-ephedrine (IR,2S-(-)- ephedrine and D-pseudoephedrine (IS,2S-(+)- ephedrine); lesser alkaloids L-norephedrine, D-norpseudoephedrine; flavonoid glycosides; glycans (ephedrans); citric, malic, and oxalic acids; proanthocyanidins (condensed tannins); tannins; volatile oils (1-alpha-terpineol, limonene, linalool).


Commercial Preparations

Chinese ephedra is available as dried and liquid preparations derived from the dried young herbaceous stems and branchlets of Ephedra sinica harvested in the fall. Products typically have a minimum of 0.8% total alkaloid content, calculated as ephedrine. Some ephedra preparations are made from E. equisetina, E. intermedia, and other species containing ephedrine.


Medicinal Uses/Indications

Traditional uses: Bronchial asthma, cold, flu, fever, chills, lack of perspiration, headache, nasal congestion, aching joints and bones, and cough.

Conditions: Cough, bronchitis, bronchial secretion, mild forms of airway disease (especially those resulting from spastic disorders), allergic rhinitis, sinusitis.

Clinical applications: Diseases of the respiratory tract with mild bronchospasms in adults and children over the age of 6; bronchodilators in the treatment of mild to moderate asthma; hay fever; common cold; weight-loss aid.


Pharmacology

Chemically similar to epinephrine, ephedrine functions indirectly as a sympathomimetic drug, both accelerating and enhancing the intensity of respiration. Its stimulatory effects on the heart induce cardiac automaticity.

In in vivo studies, both ephedrine and ephedra extracts inhibited tracheal or bronchial mucosa-induced coughing in anesthetized animals. The bronchodilating and antitussive actions of ephedrine account for suppression of the cough reflex. These effects are due to the stimulant activity of ephedrine on the central nervous system. There is also evidence that ephedra exhibits peripheral vasoconstricting effects. The activity of pure (-)-ephedrine is more potent than that of whole-herb extracts.

In other animal experiments, ephedra increased the endurance of rodents on immobilization and coldness tests. Administered singly, ephedrine induced weight loss and reduction in body fat through thermogenesis in vivo.

However, clinical studies on the effects of ephedrine on loss of weight and body fat are conflicting. While ephedrine appears to be efficacious for weight loss in individuals with thermogenic deficiencies, it is not effective in people whose basal metabolic rates are not impaired. In other human investigations, ephedra extracts increased T-lymphocytes in healthy subjects. An aqueous decoction and volatile oil showed diaphoretic properties in humans.


Dosage Ranges and Duration of Administration
  • Infusion or decoction: 1.2 to 2.3 g in 150 ml water
  • Fluid extract (1:1): 1.2 to 2.3 ml
  • Tincture 1:5 (g/ml): 5.75 to 11.5 ml

The maximum dose for children is 2 mg/kg body weight. Ephedra products should be used only on a short-term basis for up to three months. A repeated course is feasible. However, prolonged use carries a risk of tachyphylaxis and addiction.


Side Effects/Toxicology

Ephedra can produce adverse side effects of irritability, motor restlessness, insomnia, headaches, nausea, vomiting, and urinary complaints. Excessive dosing can induce tachycardia, cardiac arrhythmia, palpitations, and drug dependency.


Warnings/Contraindications/Precautions

Ephedra is contraindicated in patients who have anxiety, restlessness, hypertension, narrow-angle glaucoma, cerebral circulatory impairment, prostatic adenoma with residual urine accumulation, thyrotoxicosis, and diabetes. It is also contraindicated for individuals taking antihypertensives or antidepressant therapy.


Interactions

While no specific drug interactions have been reported for the herb, the active ingredients of ephedra, ephedrine and pseudoephedrine, have several documented interactions with monoamine oxidase inhibitors (Dingemanse 1993; Dingemanse et al. 1996); tricyclic antidepressants (Boada et al. 1999); narcotic analgesics (Dambisya et al. 1991); antihypertensive medications (particularly clonidine) (Goyagi et al. 1998; Hayakawa-Fujii et al. 1999); xanthine derivatives such as theophylline and caffeine (Bahner et al. 1993; Dawson et al. 1995; Heiss and Podreka 1978); aspirin (Horton and Geissler 1991); and amphetamine-derivatives (Clarkson and Thompson 1997). The isolation of individual ingredients from a complex compound is not necessarily equivalent to testing the complete product; however, for safety, it is important to assume that interactions with the herb may be similar. 

Ephedra should not be used with prescription or over the counter medications containing ephedrine, pseudoephedrine, or phenylpropanolamine, which are ingredients found commonly in nasal decongestants and weight loss products.


Regulatory and Compendial Status

Internal use of ephedra is approved by the German Commission E for diseases of the respiratory tract with mild bronchospasms in adults and children over the age of 6.


References

Aviado DM. Antitussives with peripheral actions. In: Pharmacological Principles of Medical Practice. Baltimore: Williams & Wilkins Co; 1972:505-407.

Bahner DR, Frenia ML, Augenstein WL. Theophylline toxicity from an over-the-counter preparation. J Emerg Med. 1993;11:427-430.

Blumenthal M, ed. The Complete German Commission E Monographs: Therapeutic Guide to Herbal Medicines. Boston: Integrative Medicine Communications; 1998:125-126.

Blumenthal M, Goldberg A, Brinckmann J. Herbal Medicine: Expanded Commission E Monographs. Boston: Integrative Medicine Communications; 2000:111-117.

Boada S, Solsona B, Papaceit J, Saludes J, Rull M. Hypotension refractory to ephedrine after sympathetic blockade in a patient on long-term therapy with tricyclic antidepressants [in Spanish]. Rev Esp Anestesiol Reanim. 1999;46(8):364-366.

Bradley P, ed. British Herbal Compendium. Vol. I. Dorset, England: British Herbal Medicine Association; 1992.

Bruneton J. Pharmacognosy, Phytochemistry, Medicinal Plants. Paris: Lavoiser Publishing; 1995.

Clarkson PM, Thompson HS. Drugs and sport. Research findings and limitations. Sports Med. 1997;24(6):366-384.

Dambisya YM, Wong CL, Chan K. Ephedrine and phenylpropanolamine potentiate the lethal toxicity of morphine and codeine in naïve mice. Asia Pacific J Pharmacol. 1991;6(3):255-258.

Dawson JK, Earnshaw SM, Graham CS. Dangerous monoamine oxidase inhibitor interactions are still occurring in the 1990s. J Accid Emerg Med. 1995;12(1):49-51.

Dingemanse J. An update of recent moclobemide interaction data. Int Clin Psychopharmacol. 1993;7(3&4):167-180.

Dingemanse J, Guentert T, Gieschke R, Stabl M. Modification of the cardiovascular effects of ephedrine by the reversible monoamine oxidase A—inhibitor moclobemide. J Cardiovasc Pharmacol. 1996;28:856-861.

Goyagi T, Tanaka M, Nishikawa T. Oral clonidine premedication enhances the pressor response to ephedrine during spinal anesthesia. Anesth Analg. 1998;87(6):1336-1339.

Gruenwald J, Brendler T, Jaenicke C, et al., eds. PDR for Herbal Medicines. Montvale, NJ: Medical Economics Company; 1998:826-827.

Hayakawa-Fujii Y, Iida H, Dohi S. Propofol anesthesia enhances pressor response to ephedrine in patients given clonidine. Anesth Analg. 1999;89(1):37-41.

Heiss WD, Podreka I. Assessment of pharmacological effects on cerebral blood flow. Eur Neurol. 1978;17(Suppl. 1):135-143.

Horton TJ, Geissler CA. Aspirin potentiates the effect of ephedrine on the thermogenic response to a meal in obese but not lean women. Int J Obes. 1991;15:359-366.

Hosoya E. Studies on the construction of prescriptions in ancient Chinese medicine. In: Chang HM, Yeung HW, Tso WW, Koo A, eds. Advances in Chinese Medicinal Material Research. Singapore: World Scientific Publications; 1985:73-94.

Leung AY, Foster S. Encyclopedia of Common Natural Ingredients Used in Food, Drugs, and Cosmetics. 2nd ed. New York: John Wiley and Sons, Inc; 1996.

Murray M. The Healing Power of Herbs: The Enlightened Person's Guide to the Wonders of Medicinal Plants. 2nd ed. Rocklin, Calif: Prima Publishing; 1995:108-115.

Robbers JE, Tyler VE. Herbs of Choice: The Therapeutic Use of Phytomedicinals. New York: Haworth Herba Press; 1999.

Shulz V, Hansel R, Tyler V. Rational Phytotherapy: A Physician's Guide to Herbal Medicine. 3rd ed. Berlin: Springer; 1998:151-152.

Thomson WA. Medicines from the Earth: A Guide to Healing Plants. Alfred Van Der Marck Editions. Maidenhead, England: McGraw-Hill; 1978:62.

Tyler V. The Honest Herbal: A Sensible Guide to the Use of Herbs and Related Remedies. 3rd ed. Binghamton, NY: Pharmaceutical Products Press; 1993:119-121.


Copyright © 2000 Integrative Medicine Communications

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