I trawled the medical Iiterature but was personally unable to find and evidence of interaction between echinacea and the statins. In fact I found a specific reference to there being no interaction. (
http://www.drugs.com/drug-interactions/e…
Rhianna did find this article by Julie Rehmeyer,a freelance math and science writer and the math columnist for Science News.
'Echinacea also may well interact negatively with many common prescription drugs, like statins, antidepressants, and protease inhibitors for HIV.'
(
http://www.consumeraffairs.com/news04/20…
After much effort she found the origin of her comment. (
http://www.healthline.com/interactions/s…
'simvastatin + echinacea » Moderate
MONITOR: Concomitant use of echinacea with other agents known to induce hepatotoxicity may increase the risk of liver injury. Use of echinacea beyond eight weeks may have adverse effects on the liver, although the magnitude of its hepatotoxic potential is unclear.'
In fact this was based on the double jeopardy theory, indicating a worst scenario theoretical risk, without any evidence that the risk was in fact real.
I would say therefore that, in answer to your question there is really no actual evidence of interaction risk, rather a theoretical suggestion that risk may exist.
Whether this is the case or not I must strongly back up her comments that there is no case at all for stopping your statin.
I do worry about the illogical use of preparations such as echinacea, not only as Rhianna points out, is it worthless as a viral treatment and prophylactic, but Echinacea should not be taken for more than 8 weeks without a break because daily use for a long time may suppress the immune system. (Merck manual).
Because of immune system effects, echinacea should be avoided in patients with active infections or wounds, recent or impending surgery, tuberculosis, autoimmune disorders including systemic lupus or multiple sclerosis, immunosuppressive disorders such as HIV, and in patients who are transplant recipients. Ironically it is recomended for use as a long term cold preventative despite the fact that the largest and best controlled study of its use indicated it to be worthless. (
http://www.medicine.ox.ac.uk/bandolier/b… and if anything there are serious concerns that chonic ingestion actually supresses the immune system! (
http://mediwire.sma.org/main/Default.asp…
With regard to your comment that 'it works for me', unfortunately an individual's assessment that a particular remedy is sucessful, is statistically irrelevent, as am sure that your husband, as a microbiologist, can confirm. Not only can an individual not link cause and effect, but also the placebo effect with regard to medication, depending on the condition, can reach rates of as much as 70%!