The Times
London, UK
8 April, 2006


If you want to protect your immune system it’s best to handle echinacea with care

HEADLINES this week claimed that one in four prescription medicines will not work properly if taken at the same time as the popular herbal remedy echinacea, used to boost the immune system.

A pharmacologist from the Indiana University School of Medicine showed that it increases the activity of an enzyme involved in processing about a quarter of all prescription drugs, including asthma treatments such as theophylline, SSRI antidepressants like Prozac, statins, and even coffee. As a result, these drugs leave the body too quickly.

So what should echinacea users do? We’re unlikely to get help from the labels on the packet. Beyond the catch-all “not to be taken in pregnancy”, few herbal medicines, even those with known interactions, such as gingko with aspirin, include this information on the packet.

Another problem is that echinacea products vary widely in terms of how strong they are. There are several species, and some products are made from leaves, flowers and stems (aerial portion), and others from their roots, or both. There is also a wide range of extraction methods and suggested doses.

The evidence suggests that those preparations that have most effect are those which include aerial portions of an echinacea variety called E. purpurea, and which have a high content of the chemical phenol. So if you want to really boost your immune system, check the type of echinacea being used and the phenol content. The flipside of getting a preparation that works, of course, is that it is also the type most likely to inferfere with your medicines.

So you’ll need to check whether any drugs that you are taking are of the type that interact. My advice would be to talk to your pharmacist when picking up your prescriptions, as they should know whether the medicines are dependent on CYP3A or CYPIA2 for clearance. This might sound like nonsense, but it is important because these are the enzymes that echinacea affects. You could try asking your GP, but the chances are that he or she will look blank and seek refuge in textbooks unthumbed since med school.

Although there’s evidence that echinacea shortens colds once they’ve started, it doesn’t seem to have a preventive role when taken regularly, so it shouldn’t be taken long-term anyway. If you take prescription medicines that are affected by it, check whether a short burst when you have an impending cold is OK. And if you have an autoimmune disease such as rheumatoid arthritis or MS, or take drugs to suppress your immune system, echinacea should not be taken at all.



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