Ephedra toxicity

Haller and Benowitz evaluated 140 reports of ephedra-related toxicity and concluded that 31% of the cases were definitely related to ephedra toxicity and a further 31% were possibly related 47% of reports of ephedra toxicity involved cardiovascular problems and 18% involved problems with the CNS. Hypertension was the single most frequent adverse reaction, followed by palpitation, tachycardia, stroke and seizure. Ten events resulted in death and 13 events caused permanent disability. The authors concluded that use of dietary supplements that contains ephedra may pose a health risk. ... 

Ephedrine is an alkaloid that is present in various forms of the ephedrine family, and which is still extracted from Ephedra sinica and Ephedra equisetina. Because of the presence of two asymmetric atoms, there are four isomeric forms. Pseudoepinephrine (d-isoephrine) is a stereoisomer with pharmacological action that differs slightly from ephedrine. The pharmacological action of ephedrine is typical of noncatecholamine sympathomimetics of mixed action. It stimulates both a- and 8-adrenoreceptors, and simultaneously causes a release of norepinephrine from synaptic neurons. Its vasoconstrictive ability is approximately 100 times weaker than that of epinephrine however, the duration of action is approximately 10 times longer. It is much less toxic than epinephrine, which allows it to be used widely in medicine. 

Ephedra, Ma-huang Diet aid stimulant bronchodilator Central nervous system toxicity, cardiac toxicity Avoid in patients at risk for stroke, myocardial infarction, uncontrolled blood pressure, seizures, general anxiety disorder... 

Ephedra distachya L. China 1-ephedrine, 1-methylephedrine, 1-norephedrine, methylephedrine, d-pseudoephedrinem, d-N-methy lpseudoephedrine. 30-3133 This herb is toxic. Treat asthma, sympathomimetic action, relieve headache, body ache, and coughing, lower fever by increasing perspiration. 

At higher doses, ephedra may be toxic. An overdose of ephedra can cause nausea, vomiting, fever, palpitations, tachycardia, hypertension, psychosis, respiratory depression, convulsions, and coma. 

There are very few animal studies conducted investigating the toxic effects of ephedra. Studies using ephedrine in animals suggest that if it is given in excessive amounts, it produces symptoms of sympathetic stimulation, manifested by anxiety and restlessness. If the dosage is large, muscular tremors and even convulsions may occur. 

Ephedra has been used as a natural medicine for thousands of years by numerous cultures with very little concern about toxicity. Its most recent popularity is related to its purported weight loss or performance enhancing attributes. In spite of that in 2004, concerns over safety resulted in the banning of all over-the-counter (OTC) sales of ephedra-containing dietary supplements by the Food and Drug Administration. 

Ma huang (ephedra) is commonly found in herbal weight loss products that are often referred to herbal fen-phen. Some weight loss clinics and herbal outlets promote Herbal fen-phen as an alternative to fenfluramine, the prescription drug that has been withdrawn from the market due to toxicity. Herbal fen-phen products sometimes contain St John s wort and are sold as herbal prozac . Ephedra-containing products are also marketed as decongestants, bronchodilators and stimulants. Other promoted uses include bodybuilding and enhancement... 

Antidepressants selective serotonin reuptake inhibitors, tricyclic antidepressants Antihypertensives felodipine Antibiotics quinolones, isoniazid Bronchodilators albuterol, theophylline Corticosteroids prednisone Dopa agonists levodopa Herbals ma huang, ginseng, ephedra Nonsteroidal anti-inflammatory drugs ibuprofen Stimulants amphetamines, methylphenidate, caffeine, cocaine Sympathomimetics pseudoephedrine Thyroid hormones levothyroxine Toxicity anticholinergics, antihistamines, digoxin Withdrawal alcohol, sedatives... 

III. Clinical presentation will depend on the toxic constituent of the herbal product, and may be acute in onset (for example, with the cardiac stimulant effects of ephedra or guarana) or delayed (as with Chinese herbal nephropathy due to Aristolochia fangchi). Allergic reactions to botanical products may manifest with skin rash, including urticaria, bronchospasm, or even anaphylaxis. 

A. PPA, phenylephrine, and ephedrine have low toxic therapeutic ratios. Toxicity often occurs after Ingestion of just 2-3 times the therapeutic dose. Strokes and cardiac toxicity have been reported after therapeutic doses of ephedra and PPA. 

As noted earlier, it is scienti cally valid to evaluate the safety of a natural mixture based on its chemical composition. Fundamentally, it is the interaction between one or more molecules in the natural product and macromolecules (proteins, enzymes, etc.) that yield the biological response, regardless of whether it is a desired functional effect such as a pleasing taste or a potential toxic effect such as liver necrosis. Many of the advertised bene cial properties of ephedra are based on the presence of the central nervous system stimulant ephedrine. So too, the gustatory and olfactory properties of coriander oil are, in part, based on the binding of linalool, benzyl benzoate, and other molecules to the appropriate receptors. It is these molecular interactions of chemical constituents that ultimately determine conditions of use. 

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