The Contraindications Of Milk Thistle

Milk thistle is an herb that protects the liver from toxins. It has antioxidant and anti-inflammatory properties that contribute to its ability to enhance liver cell regeneration. It is frequently co-administered with drugs such as acetaminophen (Tylenol) for its ability to support liver functions. Although milk thistle protects the liver from drug damage and helps reduce drug toxicity, certain herb-drug interactions call upon caution to use. Also, milk thistle may cause mild side effects that include stomach upset and diarrhea.

Hormone-dependent Conditions

Although generally regarded as a safe herbal supplement ,there are certain contraindications related to the herbs' possible estrogenic effects. According to a comprehensive review of milk thistle published by the University of Maryland, people with a history of hormone-related cancers, should avoid milk thistle. This includes cancer of the breast, ovaries, uterus and prostate. Other hormone-related conditions with which milk thistle should not be used include endometriosis and uterine fibroids.

Transplant and HIV/AIDS Drugs

Milk thistle use is contraindicated in cases of transplant patients taking immunosuppressive drugs such as cyclosporine and ProGraf due to increased hepatic clearance. Although a popular liver remedy, co-administration with immunosuppressive drugs can be dangerous since milk thistle reduces drug bioavailability, and may increase the chance of organ or tissue rejection by the body of the transplant recipient. On a similar note, milk thistle may increase the levels of protease inhibitors and non-nukes taken by people with HIV/AIDS, which can cause unwanted or even dangerous side effects.

Other Possible Interactions

Milk thistle is contraindicated in the case of pregnant or breast-feeding women due to insufficient information regarding the safety of milk thistle during pregnancy and lactation. According to a comprehensive article published by the University of Maryland, possible drug-herb interactions might occur with the use of antipsychotic drugs including haloperidol and phenothiazines, as well as with the drug phenytoin, which is used for seizures, and halothane, the general anesthetic. A medical practitioner should be consulted prior to use. Caution should also be taken when using milk thistle with medications that are broken down by the same liver enzymes due to possible decreased drug efficacy. Medications in this category include allergy drugs, cholesterol-lowering drugs, anti-anxiety drugs, anti-platelet and anticoagulant drugs, and certain cancer drugs. Research by Venkataramanan R, Ramachandran and V. Komoroski BJ, et al. reveal that recent experiments using milk thistle and human liver cells indicate that even small concentrations of milk thistle may significantly slow down the activity of the liver enzyme cytochrome P450 3A4 (CYP3A4) from 50 to 100 percent. Caution should be taken when using milk thistle with anti-parasite drugs such as Mepron, and sedatives/sleeping pills such as Ativan, due to possible decreased bioavailability and drug efficacy.