Ephedra (Ma Huang)
Ephedra, also known as Ma-Huang, has been used in the practice of Asian herbal medicine for over 5000 years to treat respiratory diseases such as asthma. The herb extract of ephedra is composed of several alkaloids including ephedrine, pseudoephedrine, norpseudoephedrine, methylephedrine, methylpseudoephedrine, and phenylpropanolamine. Ephedrine, the most potent, major constituent among ephedra alkaloids, is a mixed sympathomimetic agent. It directly stimulates a- and b-adrenergic receptors and indirectly increases norepinephrine release from sympathetic neurons leading to various physiologic responses. In the cardiovascular system, it increases heart rate resulting in a rise in cardiac output. It also produces peripheral vasoconstriction activity and therefore increases peripheral resistance and blood pressure. In addition, ephedrine relaxes bronchial smooth muscle by binding to the b2-adrenergic receptors in the lungs. Furthermore, ephedra easily crosses the blood-brain barrier because of its lipophilic molecular structure and causes stimulation in the central nervous system.
Ephedra's value for respiratory problems derives from the calming effect it has on spasms in the bronchial walls. At the same time, Ephedra stimulates the nervous system, and boosts the rate and strength of heart contractions. It also tends to discourage the growth of bacteria. Ephedra's effects have been known for over 4000 years. The drug is well known in China, where it goes by the name Tsaopen-Ma Huang. Its active ingredient, ephedrine, is the main component in the familiar asthma remedy, Primatene Tablets. The drug is very potent and, because of its effect on the heart, can be very dangerous when taken in excessive amounts. Ephedra grows mainly in Mongolia and the bordering area of China. The young branches and dried roots are the medicinal parts of the plant.
Ephedra, or ephedrine sulfate, is a naturally occurring substance derived from plants. Its principal active ingredient is ephedrine, which when chemically synthesized is regulated as a drug under the Federal Food, Drug, and Cosmetic Act. In recent years ephedra products have been widely promoted to boost weight loss, sports performance, and energy. In addition, ephedra is enormously popular with dieters because it suppresses appetite and boosts energy. It is known under many names including Desert or Mormon tea. In China, ephedra has been used to treat symptoms of asthma and upper respiratory infections. Because of its stimulating effect on the nervous system, ephedra can be found in some popular weight loss and energy products. It can also be found in many over-the-counter cold and allergy medications.
Ephedra's active medicinal ingredients are the alkaloids ephedrine and pseudoephedrine. Both ephedrine and its synthetic counterparts stimulate the (CNS) central nervous system, dilate the bronchial tubes, increase blood pressure, and heart rate. Pseudoephedrine (the synthetic form) is a popular over-the-counter remedy for nasal congestion.
Because ephedra is an herb, it is considered a dietary supplement regulated under the Dietary Supplement Health and Education Act of 1994. Under that law, the FDA does not review dietary supplements for safety and effectiveness before they are marketed. Rather, the law allows the FDA to prohibit sale of a dietary supplement only if it "presents a significant or unreasonable risk of injury."
Synthetic ephedrine, however, is regulated as a drug. Ephedrine-containing products taken orally can be sold over-the-counter (OTC) without premarket approval as long as they conform to the final monograph for OTC drug products used for temporary relief of asthma symptoms. Final monographs cover the formulation, use, and labeling of OTC drug products. Prescription medicines with ephedrine for uses other than those covered by the monograph require premarket review for safety and effectiveness. Synthetic ephedrine can be found in OTC and prescription drugs taken orally for temporary relief of shortness of breath, chest tightness, and wheezing due to bronchial asthma. Synthetic ephedrine can also be used as a topical nasal decongestant (nose drops, sprays, or jelly) for temporary relief of nasal congestion due to colds, hay fever, sinusitis, or other upper respiratory allergies. As a regulated drug product, synthetic ephedrine has mandatory warnings and labeling for short-term use. It also isn't allowed to be used in combination with caffeine or other stimulants that could interact with it. The controlled availability of synthetic ephedrine drug products under FDA regulation has not been reported to be associated with the same level of severe adverse events that have been reported with dietary supplements containing ephedra.