Ephedra

Synonym(s) and related species Ma huang.

It consists of the dried young stems of Ephedra gerardiana (wall.) Stapf, and E. nebrodensis (Tineo.) Stapf, Family: Gnetaceae (Ephedraceae).

Constituents

• The main active components of ephedra are the amines (sometimes referred to as alkaloids, or more properly pseudoalkaloids)

  • • • Ephedrine, pseudoephedrine, norephedrine,

      • Norpseudoephedrine, N-methylephedrine, ephedroxane, maokonine,

      • A series of ephedradines and others.

• Other constituents include the diterpenes ephedrannin A and mahuannin, catechins, and a trace of volatile oil containing terpinen-4-ol, α-terpineol, linalool and other monoterpenes.

Use and indications

• Ephedra is used traditionally for asthma, bronchitis, hayfever and colds, but recently the herb has become liable to abuse as a stimulant and slimming aid.

• For this reason the herb has been banned by the FDA in the US.

• Its main active constituents are ephedrine and pseudoephedrine; however, ephedra herb is claimed to have many more effects than those ascribed to ephedrine and its derivatives.

• It is these compounds that also give rise to the toxic effects of ephedra.

Ephedra + Caffeine

Ephedrine can raise blood pressure and in some cases this may be further increased by caffeine. Combined use has resulted in hypertensive crises in a few individuals. Isolated reports describe the development of acute psychosis when caffeine was given with ephedra.

Mechanism

Ephedrine and caffeine may cause catecholamine release and an increase in intracellular calcium release which leads to vasoconstriction. Myocardial ischaemia may occur as a result of this vasoconstriction (in the coronary artery), and this may result in myocardial necrosis and cell death.

1. Haller CA, Benowitz NL. Adverse cardiovascular and central nervous system events associated with dietary supplements containing ephedra alkaloids. N Engl J Med (2000) 343, 1833–8.

2. Shekelle PG, Hardy ML, Morton SC, Maglione M, Mojica WA, Suttorp MJ, Rhodes SL, Jungvig L, Gagne J. Efficacy and safety of ephedra and ephedrine for weight loss and athletic performance: a meta-analysis. JAMA (2003) 280, 1537–45.

3. Tormey WP, Bruzzi A. Acute psychosis due to the interaction of legal compounds - ephedra alkaloids in ‘Vigueur Fit’ tablets, caffeine in ‘Red Bull’ and alcohol. Med Sci Law (2001) 41, 331–6.

4. Kaberi-Otarod J, Conetta R, Kundo KK, Farkash A. Ischemic stroke in a user of Thermadrene: a case study in alternative medicine. Clin Pharmacol Ther (2002) 72, 343–6.

5. Dunnick JK, Kissling G, Gerken DK, Vallant MA, Nyska A. Cardiotoxicity of Ma Huang/caffeine or ephedrine/caffeine in a rodent model system. Toxicol Pathol (2007) 35, 657–64.

6. Nyska A, Murphy E, Foley JF, Collins BJ, Petranka J, Howden R, Hanlon P, Dunnick JK. Acute hemorrhagic myocardial necrosis and sudden death of rats exposed to a combination of ephedrine and caffeine. Toxicol Sci (2005) 83, 388–96.