Black willow (generic name)
treats Rheumatoid arthritis, Osteoarthritis, Lower back pain, and Headache
Table of Contents
Top Learning Centers(Recursos en Español)
Interactions with Drugs
Use of acetazolamide and salicylates may cause lethargy, incontinence, and confusion. Caution is advised in patients taking acetazolamide, a carbonic anhydrase inhibitor, which is often used in treating glaucoma or acute mountain sickness. Taking carbonic anhydrase inhibitors with willow bark may increase the therapeutic and toxic effects of both the carbonic anhydrase inhibitor and the salicylate.
Salicis cortex extract 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, anti-platelet drugs such as clopidogrel (Plavix®), and non-steroidal anti-inflammatory drugs (NSAIDS) such as ibuprofen (Motrin®, Advil®) or naproxen (Naprosyn®, Aleve®). Willow bark may also have anti-inflammatory effects. When willow bark is taken in combination with sulfinpyrazone, it may theoretically result in additive anti-platelet effects, which may increase bleeding time.
Willow bark extract may induce hypertriglyceridemia (excess of triglycerides in the blood) or cause blood pressure instability. Patients taking blood pressure medications should consult with a qualified healthcare professional, including a pharmacist. Monitoring may be necessary. Theoretically, the concomitant use of beta-blockers with willow bark may impair the effectiveness of beta-blockers due to willow bark's proposed aspirin-like pharmacological actions.
Theoretically, the concomitant use of diuretics with willow bark may reduce the effectiveness of diuretics and may enhance the risk for salicylic acid toxicity. White willow may also decrease the renal (kidney) excretion of methotrexate resulting in toxic levels due to its salicin content.
Theoretically, the concomitant use of phenytoin (Dilantin®) with willow bark's salicylates may increase the Dilantin® levels in the blood, resulting in toxicity.
Theoretically, the concomitant use of probenecid with willow bark may impair the effectiveness of probenecid.
Due to the plasma protein-binding salicylate component of white willow bark, some other plasma protein-bound drugs may be displaced, possibly resulting in altered drug levels. Consult with a qualified healthcare professional, including a pharmacist, for a full list of these agents.
Willow bark plus spironolactone may result in antagonistic or additive effects.
Theoretically, the concomitant use of sulfonylureas with willow bark may increase the effect of sulfonylureas, possibly increasing the side effects and toxicity.
Theoretically, white willow bark may impair the effectiveness of valproic acid.
Interactions with Herbs and Dietary Supplements
Willow bark extract may induce hypertriglyceridemia (excess of triglycerides in the blood) or cause blood pressure instability. Patients taking herbs and supplements that affect blood pressure or cholesterol should use willow bark cautiously.
Willow bark may be contaminated with high levels of cadmium, which may increase concentrations of cadmium in the body. Consumers should select tested brands to avoid using contaminated products.
Theoretically, the concomitant use of diuretics (increases urine flow) herbs or supplements with willow bark may reduce the effectiveness of the diuretic and may enhance the risk for salicylic acid toxicity. Consult with a qualified healthcare professional, including a pharmacist, before combining therapies.
Willow bark may increase the risk of bleeding when taken with herbs and supplements that are believed to increase the risk of bleeding. Multiple cases of bleeding have been reported with the use of Ginkgo biloba, and fewer cases with garlic and saw palmetto. Numerous other agents may theoretically increase the risk of bleeding, although this has not been proven in most cases.
Willow bark may have anti-inflammatory effects and may interact positively with guaiacum resin, black cohosh, sarsaparilla, and poplar bark to reduce chronic arthritic pain symptoms.
The concomitant administration of tannin-containing herbs or supplements may result in the malabsorption of salicylic acid.