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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.