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Ephedra. Ephedra -Habit. Ephedra. An evergreen shrub native to central Asia Predominant active alkaloid- ephedrine Other active alkaloids include: pseudoephedrine norephedrine norpseudoephedrine. Ephedra - T.S. stem. Ephedra strobilus. Ephedra - Male cone. Ephedra - Female cone.
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Ephedra • An evergreen shrub native to central Asia • Predominant active alkaloid- ephedrine • Other active alkaloids include: pseudoephedrine norephedrine norpseudoephedrine
Traditional Uses of Ephedra (ma huang) • Tea prepared from dried, comminuted branches • Used for ~5000 yrs. by practitioners of traditional Chinese medicine (TCM) to treat asthma, flu, and nasal congestion • Combined with other herbs to enhance or decrease effects
History of Conventional Uses of Ephedra • 1887- Ephedrine first isolated by Japanese chemist, N. Nagai • 1920’s- Series of studies on ephedrine’s pharmacological properties leads to synthetic production • 1927- Widely used as a nasal decongestant, central nervous system stimulant, and to treat bronchial asthma • 1950’s- Many reports of side effects such as blood pressure and heart rate lead pharmaceutical companies to switch to pseudoephedrine
Physiological Effects • Strong stimulant- enhances the release of norepinephrine (NE) from sympathetic nerve endings (see handout) • Has 1 and 2 agonist activityrelaxes bronchial muscles • Has 1, 2, 1, and 2 adrenergic activityleads to less desirable effects such as blood pressure, heart rate, and nervousness • To compensate, the body releases adenosine and prostaglandin (PG) which inhibit the release of NE
Physiological Effects • Caffeine and aspirin may inhibit and/or reduce the effects of adenosine and PG continued NE activation • “ECA” stack • ephedrine alkaloids (ma huang) • caffeine (Gaurana, Bissey Nut, Kola) • aspirin/salicin (Willow Bark extract)
Reported Benefits • Increased weight loss due to thermogenic effect • Enhanced athletic performance • Increased energy • 3 billion servings sold during 1999 12 million people using ephedra
Adverse Effects • Dizziness, tremors, irregular heart rate myocardial infarctions, strokes • May induce psychological dependence • 1993-2003- FDA documented 2,277 adverse event reports (AER) concerning cardiovascular, neurological and psychiatric effects (~1% of total?) • Type ‘A’ AE- directly related to the pharmacological actions of the active ingredient • Type ‘B’ AE- rare and difficult to separate from pre-existing conditions; cause/effect hard to prove