What medications can interact with isoflavones?

Isoflavones may increase the risk of bleeding when taken with drugs that increase the risk of bleeding. Some examples include aspirin, anticoagulants (blood thinners) such as warfarin (Coumadin®) or heparin, antiplatelet drugs such as clopidogrel (Plavix®), and nonsteroidal anti-inflammatory drugs such as ibuprofen (Motrin®, Advil®) or naproxen (Naprosyn®, Aleve®).

Isoflavones may lower blood sugar and insulin levels. Caution is advised when using medications that may also lower blood sugar. Patients taking drugs for diabetes by mouth or insulin should be monitored closely by a qualified healthcare professional, including a pharmacist. Medication adjustments may be necessary.

Isoflavones may interfere with the way the body processes certain drugs using the liver's cytochrome P450 enzyme system. As a result, the levels of these drugs may be altered in the blood and may cause altered effects. Patients using any medications should check the package insert and speak with a qualified healthcare professional, including a pharmacist, about possible interactions.

Isoflavones may affect blood pressure. Caution is advised in patients taking blood pressure-altering agents, due to the potential of isoflavones to have either additive or antagonistic effects with blood pressure-lowering agents.

Because isoflavones contain estrogen-like chemicals, possible interactions may occur when combined with other estrogenic agents.

Isoflavones may also interact with agents used for the heart, agents that affect the immune system, agents that affect blood vessel width, alzheimer's agents, antibiotics, anticancer agents, aromatase inhibitors, calcitriol, cholesterol- and lipid-lowering agents, cystic fibrosis transmembrane conductance regulator (CFTR) agents, diuretics (such as furosemide), gastrointestinal agents, hormonal agents (such as progesterone, luteinizing hormone, testosterone, and follicle-stimulating hormone), indomethacin, methotrexate, neurologic agents, osteoporosis agents, p-glycoprotein-regulated agents, selective estrogen receptor modifiers (SERMs, such as tamoxifen), thyroid hormones, tyrosine kinase inhibitors, and weight loss agents.

You should read product labels, and discuss all therapies with a qualified healthcare provider. Natural Standard information does not constitute medical advice, diagnosis, or treatment.