Message Number: FHL8520 | New FHL Archives Search
From: "Tressie"
Date: 2009-03-25 15:43:10 UTC
Subject: [ferrethealth] Re: Milk Thistle cautions
To: ferrethealth@yahoogroups.com


I received an email from someone who kindly recommended that I might try Mi=
lk Thistle (Silybum marianum) as a supplement that could help with Linguini=
's hepatitis, which has prompted this post.

>From my work in human oncology I am aware that herbal supplements can be be=
neficial however, should be used with caution and always in consultation wi=
th one's physician, or in our cases, a veterinarian.

Some research has been done on herbal remedies in animals. Knowledge about =
the effects of these substances on animal companions is generally extrapola=
ted from data for humans or is based on anecdotal reports, although there a=
re `Holistic' veterinarians who are trained specifically in the use of herb=
s in animals. The published research on milk thistle and pets seems to focu=
s on canines.

In humans we know that herbal supplements can interact with prescription an=
d over-the-counter medications. Such interactions may intensify or reduce t=
he effectiveness of a drug or cause a serious side effect. Before giving su=
pplements to a ferret, people should consult with their veterinarian, so th=
at such interactions can be avoided. Many herbs can induce or inhibit liver=
and intestinal drug metabolizing enzymes, leading to altered drug concentr=
ation and clearance.

The seeds of the milk thistle plant are commonly used to protect the liver =
from damage caused by such things as hepatitis viruses as well as chemother=
apy drugs and other substances. Compounds found in milk thistle, i.e., syli=
bin, sylimarin act as antioxidants and also stimulate the repair of the liv=
er. However, one must exercise caution in using milk thistle (and other he=
rbs) because it appears that these and possibly other compounds in milk thi=
stle can have other effects.

Researchers have found that milk thistle can alter the activity of enzymes =
in the liver. This is important to know because enzymes in the liver break =
down many of the substances that are ingested, including medications. If th=
e activity of these enzymes is reduced, then drugs remain in the blood long=
er than they otherwise might. This could lead to having higher-than-expecte=
d levels of drugs in the body, causing side effects or intensifying already=
-existing side effects. In recent experiments using milk thistle researcher=
s found that relatively small concentrations of milk thistle did significan=
tly slow down the activity of the liver enzyme CYP3A4 by 50% to 100%.

Many medications are processed by this liver enzyme. If milk thistle is tak=
en it has the potential to raise levels of certain drugs, causing unpleasan=
t or even dangerous side effects. On the other hand it can also lower leve=
ls of other drugs in the system, reducing their efficacy.

Below is a short list of some medications that are processed through the CY=
P3A4 enzyme and that are routinely prescribed for ferrets.

Increased blood level concentrations if combined with Milk Thistle:

Cisapride
Cimetidine
Clarithryomycin
Erythromycin

Decreased blood level concentrations if combined with Milk Thistle:

Prednisone/prednisolone
Metronidazole

Now in Linguini's case she is on Azathioprine (Imuran), which is NOT metabo=
lized by CYP34A. Still I will check with my vet to make sure it is okay f=
or her to take it.

Tressie

REFERENCES

Saller, R., Melzer, J., Reichling, J., Brignoli, R. & Meier, R. (2007). An =
updated systematic review of the pharmacology of silymarin. Forschende Komp=
lement=E4rmedizin, 14(2), 70-80.

Wynn, S.G., & Foug=E8re, B. (2007). Veterinary herbal medicine. Chatswood:=
Elsevier Health Sciences.





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