Description
Ephedrine is an alkaloid, which is from dry grass stems of ephedra plants such as
ephedra, zhong ephedra, or ephedra. Ephedra is an
herb recorded in “Chinese Pharmacopoeia,” which can be used for sweating and
cold, adjustment of lung function, asthma, and swelling. Ephedrine can treat cold,
chest tightness, bronchial asthma, and so on. Ephedra was used as a drug in China
for more than 2000 years, which was recorded in history books of materia medica.
Ephedra is also known as Longsa recorded in the book Shen Nong’s Herbal Classic
of Materia Medica, Bixiang recorded in the book Another record by famous record,
and Gougu recorded in the book Guang Ya. Ephedra was firstly recorded in the book
Shen Nong’s Classic of Materia Medica.
Chemical Properties
White Solid
Physical properties
Appearance: a white needle-like crystal or crystalline powder, odorless, and tastes
bitter. Solubility: soluble in water and can be dissolved in ethanol but insoluble in
chloroform or ether. Melting point: 217–220 °C.
History
In traditional Chinese medicine (TCM), ephedrine and pseudoephedrine are main
active ingredients in “herbal ephedra” . Organic chemist, Changi Changyi (1844–
1929), from Japan first isolated ephedrine from the herb “Shuanghui Ephedra” in
1885 . Ephedrine was successfully synthesized by chemist Ernst Sp?th from
Austria (1886–1946) in 1920 . Kehui Chen (1898–1988) and its co-colleague
Carl F. Schmidt extracted ephedrine from ephedra in 1923 and then clarified the
pharmacological effects of ephedrine, which attracted the attention from Europe
and the United States. Ephedrine was approved in clinical practice by the FDA of
the United States. Structure of ephedrine was analyzed by Changi Changyi in 1926.
Uses
bronchodilator, cardiac stimulant
Uses
α- and β-Adrenergic agonist. Bronchodilator.
Flammability and Explosibility
Nonflammable
Pharmacology
Ephedrine has a similar effect with adrenaline. Ephedrine can bind α, β receptors
and activate the receptor as adrenaline. Ephedrine makes the adrenergic nerve endings
release medium and indirectly play the role of adrenaline. Ephedrine is stable
and its effect is weaker than adrenaline, and the central excitatory effect is more
obvious. Ephedrine can relax bronchial smooth muscle but less durable than adrenaline.
Ephedrine can also relieve bronchial spasm, excite the heart, enhance myocardial
contractility, and speed up the heart rate. However, its role in increasing the
heart rate may be weakened by the vagus nerve excitement caused by increased
blood pressure . Ephedrine accelerates heart rate and increases cardiac contractility
by stimulating the beta receptor. Ephedrine stimulates the alpha receptor and
contracts the arterial effect, but the contraction of the rabbit aorta is dominated by
direct action. In recent years, ephedra has been found to have a role inhibiting the
formation of acute blood clotting, promote fat synthesis in fat, and scavenge oxygenfree
radicals.
Clinical Use
In clinical practice, ephedrine hydrochloride was used for the treatment of bronchial
asthma, hypotension, central excitation , and toxicity by morphine and barbiturate.
Ephedrine hydrochloride was also used to eliminate nasal mucosal congestion.
Drug tolerance can occur quickly when ephedrine hydrochloride was used often in
a short time. Ephedrine hydrochloride can also be used for hypotension and chronic
hypotension caused by subarachnoid anesthesia or epidural anesthesia .
Side effects
The
side effects of ephedrine hydrochloride are anxiety, insomnia, palpitations, sweating,
and other symptoms by central excitement caused by the long-term use of large
doses which can be cured by hypnotic sedative drugs. Acute drug tolerance can be
induced by repeated use in short time.
