Ephedra adverse reactions
Clinical bottom line
Ephedra is associated with a greatly (200-fold) increased risk of adverse reactions reported by a poisons centre compared with other herbal products.
Ephedra has been used in traditional Chinese herbal products to treat asthma and other respiratory diseases. It contains several alkaloids, with ephedrine and other ephedrine-like substances. These can lead to vasoconstriction, and also affect cardiac function. It is often an ingredient in dietary supplements.
Reference
S Bent et al. The relative safety of ephedra compared with other herbal products. Annals of Internal Medicine 2003 138: 468-471.
Study
Adverse reactions to herbal products during 2001 were documented by the Toxic Events Surveillance Programme, a database maintained by poisons control centres in the USA, covering nearly all poisons centres. An adverse reaction was defined as an adverse event occurring with normal, prescribed, labelled or recommended use of the product, as opposed to overdose, misuse, or abuse.
Estimates of the number of herbal products sold in the USA during 2001 was obtained from a natural products consulting agency that sampled natural product retail stores in the USA.
Results
Table 1 shows the number of adverse reaction and sales of commonly used herbal products in the USA in 2001. There were 1,832 adverse reactions, of which 64% were related to ephedra, despite it being less than 1% of total herbal product sales.
Table 1: Ephedra adverse reactions compared with other herbal products
|
Adverse reactions |
Sales percentage |
Adverse reactions per 1% sales |
Relative risk |
|
| Ephedra |
1178 |
0.82 |
1437 |
1 |
| Ginkgo |
28 |
14.05 |
2 |
721 |
| St John's wort |
31 |
7.98 |
4 |
370 |
| Echinacea |
69 |
16.62 |
4 |
346 |
| Ginseng |
46 |
10.45 |
4 |
326 |
| Valerian |
44 |
4.78 |
9 |
156 |
| Kava |
59 |
4.3 |
14 |
105 |
| Yohimbine |
10 |
0.75 |
13 |
108 |
| All herbal products (excluding ephedra) |
654 |
99.18 |
7 |
218 |
| Relative risk is the number of adverse reactions per unit sale of ephedra divided by the number of adverse reactions per unit sale of comparator | ||||
Comment
This interesting study does not tell us the nature of the adverse reactions reported, merely that they were massively more common with ephedra than with other herbal products. There would need to be massive under-reporting of its use to invalidate these findings. There are calls for it to be banned, which are understandable.