Understanding Elderberry and Its Uses
Elderberry, derived from the Sambucus tree, is a traditional remedy that has gained modern popularity as a dietary supplement, often used to address symptoms of the common cold and flu [1.9.1]. The berries are rich in antioxidants, vitamin C, and flavonoids, which are thought to contribute to their potential health benefits [1.8.1]. While some preliminary studies suggest elderberry may help relieve upper respiratory symptoms, it's crucial to understand its pharmacological effects before combining it with prescription drugs [1.9.1].
A primary mechanism of action for elderberry is its ability to stimulate the immune system [1.3.2]. It may increase the production of cytokines, which are proteins that help regulate inflammation and immune responses [1.3.5]. While this can be beneficial for fighting infections, it poses a significant risk for individuals on medications designed to suppress the immune system.
Important Safety Note: Raw vs. Cooked Elderberry
It is essential to only consume cooked elderberry products. Raw or unripe elderberries, as well as the leaves and stems of the plant, contain cyanide-producing compounds that are toxic and can cause severe nausea, vomiting, and diarrhea [1.8.2]. Cooking destroys these toxins, making the berry safe for consumption [1.8.2].
Major Medication Interactions with Elderberry
Consulting with a healthcare provider before taking elderberry is essential, especially if you are on any regular medication [1.9.1]. The following are the most significant and well-documented interactions.
Immunosuppressants
This is the most critical interaction. Because elderberry can increase the activity of the immune system, it may counteract the effects of medications designed to suppress it [1.3.2]. This is particularly dangerous for:
- Organ Transplant Recipients: Taking elderberry could interfere with anti-rejection medications like cyclosporine or tacrolimus, potentially leading to organ rejection [1.2.1, 1.3.2].
- Patients with Autoimmune Diseases: For conditions like rheumatoid arthritis (RA), lupus (SLE), or multiple sclerosis (MS), elderberry might stimulate the immune system and cause a flare-up of symptoms [1.3.1, 1.3.6]. Medications commonly used for these conditions include steroids (like prednisone), azathioprine, and methotrexate [1.3.1, 1.3.5].
Diabetes Medications
Elderberry may lower blood sugar levels [1.4.1]. When taken alongside antidiabetic drugs (such as metformin, insulin, glipizide, or pioglitazone), there is an increased risk of hypoglycemia (abnormally low blood sugar) [1.2.4, 1.5.2]. Animal studies have suggested that elderberry extracts can modulate glucose metabolism, correct hyperglycemia, and reduce insulin resistance, but these effects in humans require more research [1.5.5]. Due to this potential additive effect, individuals with diabetes must consult their doctor before using elderberry [1.5.1].
Diuretics (Water Pills)
Elderberry itself may have a diuretic effect, meaning it helps the body get rid of excess fluid by increasing urination [1.4.2]. If taken with prescription diuretics like furosemide (Lasix) or hydrochlorothiazide, it could amplify the effect, leading to an increased risk of dehydration [1.4.1].
Theophylline
Some evidence suggests that elderberry may reduce the body's levels of theophylline, a medication used for asthma and other respiratory conditions [1.4.1]. This could make the drug less effective. One source indicates this happens because elderberry decreases the metabolism of theophylline, thereby increasing its effects, but this is listed as a minor interaction with unknown significance [1.6.2]. Given the conflicting information, caution is advised.
Chemotherapy Drugs
Elderberry may interact with some chemotherapy drugs [1.4.1]. A case report involving the chemotherapy drug pazopanib noted that taking it with elderberry might increase the risk of liver side effects [1.2.2]. The full extent of interactions with anti-cancer therapies is largely unknown, and some studies suggest it could even interfere with the efficacy of drugs like irinotecan, depending on the patient's immune status [1.7.3, 1.7.5]. Patients undergoing chemotherapy should always ask their oncologist before taking any supplements [1.7.1].
Comparison Table of Elderberry Interactions
| Medication Class | Specific Examples | Potential Interaction with Elderberry | Level of Concern |
|---|---|---|---|
| Immunosuppressants | Cyclosporine, Tacrolimus, Prednisone, Methotrexate | Decreases the effectiveness of the medication by stimulating the immune system; may cause disease flares or organ rejection [1.3.2]. | High |
| Diabetes Medications | Metformin, Insulin, Glipizide, Glyburide | May have an additive effect, increasing the risk of hypoglycemia (low blood sugar) [1.2.4, 1.5.1]. | Moderate |
| Diuretics | Furosemide (Lasix), Hydrochlorothiazide | May amplify the diuretic effect, increasing the risk of dehydration [1.4.1]. | Moderate |
| Theophylline | Theo-Dur | May reduce levels of the drug, making it less effective, though evidence is limited [1.4.1]. | Low-Moderate |
| Chemotherapy Drugs | Pazopanib, Irinotecan | May increase the risk of side effects or interfere with the drug's efficacy [1.2.2, 1.7.5]. Must consult an oncologist. | High |
| Laxatives | Senna, Bisacodyl | Elderberry can also have a laxative effect, and taking it with other laxatives could lead to severe diarrhea [1.4.4]. | Low |
Conclusion: Prioritize Safety and Professional Advice
While elderberry is a popular natural remedy, it is not without risks, especially for individuals taking certain prescription medications. Its immune-stimulating properties create significant potential interactions with immunosuppressants, making it unsuitable for organ transplant recipients and many people with autoimmune conditions [1.3.1]. Furthermore, its effects on blood sugar and fluid levels mean that people taking diabetes medications or diuretics must exercise caution [1.2.3].
Because the regulation of dietary supplements is less strict than for drugs, the composition and potency of elderberry products can vary [1.9.1]. The most crucial takeaway is to always consult with a healthcare provider or pharmacist before adding elderberry to your regimen. They can provide personalized advice based on your health status and current medications to ensure your safety.
For more information from an authoritative source, you can visit the National Center for Complementary and Integrative Health (NCCIH).
