Echinacea

Echinacea is currently one of the best selling botanical supplements on the American and worldwide herbal market. Commercial Echinacea products are manufactured from three Echinacea species, Echinacea purpurea (root or herb), E. angustifolia (roots), and E. pallida (roots). Echinacea preparations are administered orally as supportive therapy for the prophylaxis and treatment of the common cold, bronchitis, influenza, bacterial and viral infections of the respiratory tract, and urinary tract infections. How- ever, many of the clinical trials suffer from poor methodology, and recent controlled clinical trials have indicated that Echinacea products are not effective for prophylaxis of upper respiratory tract infections. The in vitro and in vivo studies indicate that the therapeutic effects of Echinacea are due to the stimulation of cellular immune response. Echinacea may also be used externally to promote wound healing, and to soothe minor inflammatory skin conditions, such as poison ivy. The major adverse events reported are allergic reactions, ranging from contact dermatitis to anaphylaxis. Patients with an allergy to plants in the daisy family (Asteraceae) should be instructed not to use products containing Echinacea . There are no drug interactions reported, and Echinacea products may be used safely in conjunction with antibiotics or sulfa drugs. However, recent in vitro studies have shown that Echinacea extracts inhibit cytochrome P450 3A4, and thus should be used cautiously in patients taking medica- tion metabolized via this route. According to the German Commission E, patients with autoimmune disorders, AIDS, HIV infection or tuberculosis should not use Echinacea , however there is little data to substantiate these contraindications. Recom- mendations for oral dosage and dosage forms are difficult due to the wide variety of preparations and doses used in the clinical trials (see dosage section). For external applications, a cream or ointment containing 15% expressed juice, is recommended.