Stinging Nettle (Urtica dioica): An Unusual Case of Galactorrhea.

BACKGROUND The increasing popularity and availability of herbal supplements among patients necessitates a better understanding of their mechanism of action and the effects they have on the body, both intended and unintended. Stinging nettle (Urtica dioica) is an herbaceous shrub found throughout the world that has been used for medicinal purposes for centuries. CASE REPORT A 30-year-old woman with obesity and GERD presented to a primary care clinic with new-onset galactorrhea. A urine pregnancy test was negative. Prolactin, thyroid-stimulating hormone (TSH), and a metabolic panel were all within normal limits. A mammogram demonstrated scattered areas of fibroglandular density and benign-appearing calcifications in the left breast. The breast ultrasound showed no suspicious findings. Her medications included intermittent Echinacea, etonogestrel implant 68 mg subdermal, and the supplement stinging nettle 500 mg, which she had been taking over the past month for environmental allergies. After consultation with a clinical pharmacist, the stinging nettle was discontinued. No additional changes to her medications or supplements were made. One week after discontinuation, she returned to the clinic with complete resolution of the galactorrhea. CONCLUSIONS Stinging nettle (Urtica dioica) is a common supplement and has effects on (1) sex hormone-binding globulin, (2) histamine-induced prolactin release, and (3) serotonin-induced release of thyrotropin-releasing hormone. The local estrogen bioactivity in breast tissue may subsequently lead to gynecomastia and/or galactorrhea. Supplements are an often overlooked but a critical component of medication reconciliation and potential clinical adverse effects.

Safety of Popular Herbal Supplements in Lactating Women.

The increasing popularity and use of dietary supplements has required health care professionals to become more knowledgeable of their properties, interactions, and adverse effects. The objectives of this review were to evaluate the safety of popular dietary supplements in breastfeeding mothers and the effects on the infants. Nine of the most popular herbal dietary supplements were identified based on the 2011 US market report of the top 10 selling botanicals and the most frequently received inquiries by the Ruth A. Lawrence Lactation Study Center at the University of Rochester Medical Center. Relevant publications were identified through June 2014 using PubMed and EMBASE; tertiary references, including the Drugs and Lactation Database and Natural Medicine Comprehensive Database, were also reviewed. These herbals include black cohosh, cranberry, echinacea, evening primrose, garlic, ginseng, melatonin, milk thistle, and St John's wort. Studies varied greatly with regard to study design, herbal intervention, and outcome measures. Findings suggested that dietary/herbal supplements have not been evaluated in high-quality clinical trials, and there is limited evidence supporting safety of use, particularly among lactating women. Therefore, it is essential for physicians to provide counseling for nursing mothers seeking information on dietary supplements, highlighting reliable safety profiles, inquiring about the potential benefits the patient is seeking, and assessing the patient's perception of this supplement during breastfeeding. More research and clinical trials are required in this area to guide the recommendations and expand our current knowledge of these products.