nettles (generic name)
- Auto Immune Conditions
- Bladder & Kidney Health
- Brain & Nervous System
- Care Transitions
- Dental Health
- Emotional Health
- Eye Health
- Falls Prevention
- Financial Planning
- General Safety
- Health Care Basics
- Healthy Living
- Hearing Loss
- Heart Health
- High Blood Pressure
- Life Transitions
- Lung Health
- Men's Health
- Nutrition & Weight Management
- Pain Management
- Preventive Health
- Sexual Health
- Stomach & Digestive Health
- Stress & Anxiety
- Women's Health
Interactions with Drugs
Alpha blockers are typically given to treat high blood pressure (hypertension) and to treat benign prostatic hyperplasia (enlarged prostate). Co-administration of nettle and alpha blockers may theoretically have an additive blood pressure lowering effect. Caution is advised.
Administration of nettle may also theoretically have an additive effect with antihypertensive (blood pressure lowering) agents.
Nettle root contains a coumarin constituent and nettle leaves contain vitamin K. Thus, nettle 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®).
Nettle leaves have been used with diclofenac in the treatment of acute arthritis.
Although not well studied in humans, administration of nettle may theoretically have an additive effect on diuretics, resulting in dehydration and abnormally low potassium concentrations in the blood (hypokalemia).
Finasteride, a 5 α-reductase inhibitor, is used in the treatment of benign prostatic hyperplasia. Co-administration of finasteride and nettle may have additive effects. Caution is advised.
Although not well studied in humans, nettle may increase blood sugar levels. Caution is advised when using medications that may alter 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.
Interactions with Herbs and Dietary Supplements
Theoretically, nettle may cause diuresis (increase in the flow of urine). Caution is advised when taking with other herbs that have a similar effect.
Although not well studied in humans, niacin may 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, such as kava, dong quai, horse chestnut and niacin, although this has not been proven in most cases. Nettle leaves may also theoretically have an additive effect with other anti-inflammatory agents.
Theoretically, nettle may increase blood glucose levels. Caution is advised when using herbs or supplements that may alter blood sugar. Blood glucose levels may require monitoring, and doses may need adjustment. Theoretically, nettle may lower blood pressure levels.
Saw palmetto and pygeum are used to treat benign prostatic hyperplasia (enlarged prostate) and may have additive therapeutic effects with nettle.
Soy isoflavones appear to inhibit type II 5 α-reductase and may have additive effects with nettle.
This information is based on a systematic review of scientific literature, and was peer-reviewed and edited by contributors to the Natural Standard Research Collaboration (www.naturalstandard.com): EP Barrette, MD (Case Western Reserve University); William Benda, MD (University of Arizona); Heather Boon, BScPhm, PhD (University of Toronto); Julie Conquer, PhD (RGB Consulting); Cynthia Dacey, PharmD (Northeastern University); Minyichel Gezahegne, PharmD (Massachusetts College of Pharmacy); Nicole Giese, MS (Natural Standard Research Collaboration); Shaina Tanguay-Colucci, BS (Natural Standard Research Collaboration); Catherine Ulbricht, PharmD (Massachusetts General Hospital); Wendy Weissner, BA (Natural Standard Research Collaboration).