Ephedra sinica, a species of ephedra (Ma huang), contains the alkaloids ephedrine and pseudoephedrine, which have been found to induce central nervous system stimulation, bronchodilation, and vasoconstriction with ephedrine toxicity associated with stroke, myocardial infarction and sudden death.
Ma huang has been used in traditional Chinese medicine for more than 5 millennia. Beverages made from the plant have been referred to under many names, e.g., yellow river, Mormon tea, and whorehouse tea. The jointed green stems of the ma huang are the chief photosynthetic organs of the plant and contain the alkaloids. In commercially available Ma huang products the percentage of ephedrine varies greatly from 1.1 to 15.3 mg per dosage unit. Ephedrine is well absorbed after oral administration is excreted primarily unchanged in the urine with a serum half-life of 2.7 to 3.6 hours. The pathogenesis of the cardiac toxic effects remains incompletely defined but probably related to increased blood pressure secondary to elevations in heart rate, cardiac output and peripheral resistance including vasoconstriction of the coronary arteries. Long term ephedrine use may lead to conditions seen with prolonged catecholamine excess resulting in fibrosis and even death.
Regulation
On February 6th, 2004 the FDA issued a final rule prohibiting the sale of dietary supplements containing ephedrine alkaloids (ephedra) because such supplements present an unreasonable risk of illness or injury. The rule became effective 60 days after date of publication. On April 14, 2005 a Federal District Court in Utah struck down the FDA ban with the ruling only specific to Utah.
Overdoses of Ephedrine cause stimulation of the sympathetic nervous system with severe cases producing cardiac arrhythmia, increased blood pressure, and possible convulsions. Adverse reactions occur between one-half to two hours following ingestion of an excessive quality of the herb. Case reports describe multiple symptoms, including palpitations, nausea, tremulousness, abdominal pain, and vomiting. Patients present with abnormal electrocardiograms. Treatment of acute toxicity is based on controlling the stimulating effects of the drug. Treatment of acute agitation with benzodiazepines and neuroleptics has been used. A variety of medications have been used to lower the blood pressure and beta blockers are beneficial for tachyarrhythmias. Decontamination with activated charcoal has been used depending on the time of presentation.
References
- Ephedrine Chemistry
- Mayo Clinic Proceedings 2002;77:12-16.
- FDA Issues Regulation Prohibiting Sale of Dietary Supplements Containing Ephedrine Alkaloids