Silver nasal sprays: misleading Internet marketing

Ear, Nose & Throat Journal, April, 2008 by Michael T. Gaslin, Cory Rubin, Edmund A. Pribitkin

Abstract

Long-term use of silver-containing products is associated with a permanent bluish-gray discoloration of the skin known as argyria, but they remain widely available despite several measures by the FDA to regulate them. Several recent case reports have described the occurrence of argyria as a result of using these "natural" products. We used the five most common Internet search engines to find Web sites providing information on silver-containing nasal sprays. Of 49 Web sites analyzed, only 2 (4%) mentioned argyria as a possible complication, although 30 (61%) did caution against long-term use. Eight sites (16%) made specific claims about the health benefits of the product. All 49 sites (100%) provided direct or indirect links to buy silver-containing nasal sprays. We conclude that information about silver-containing nasal sprays on the Internet is misleading and inaccurate. Therefore, otolaryngologists should be aware of the misinformation their patients may be receiving about these products.

Introduction

Argyria is a permanent and disfiguring bluish-gray discoloration of the skin associated with long-term use of products containing silver (see photos at http:// rosemaryjacobs.com/argyria_photos_intro.html). Silver-containing products are readily available to consumers despite the health risks associated with exposure to soluble silver compounds. Otolaryngologists should be aware of the misinformation available to consumers about these potentially dangerous products.

Silver compounds have a long history of medicinal use. The ancient physician Avicenna (980-1037 AD) is said to have been the first to describe their use as a blood purifier, a treatment for halitosis, and for heart conditions. Interestingly, Avicenna also noted that some patients using his formulations developed a bluish discoloration of the eyes, likely an early description of argyria. (1) In 1859, Frommann reported a case of argyria caused by the use of silver nitrate as an antimicrobial. (2)

In 1902, Albert C. Barnes formed the firm of Barnes & Hille, selling the product Argyrol, an antiseptic silver compound? Barnes amassed a fortune from sales of the product, (3) but he and the public did not realize the consequences of long-term use of silver. Cases of generalized argyria were more prevalent in the first half of the 20th century because of the use of silver-containing compounds as medicinals and increased occupational exposure in the silver industry. In the second half of the 20th century, widespread use of silver-containing compounds decreased as knowledge of their side effects increased.

In 1994, Congress passed the Dietary Supplement Health and Education Act (DSHEA), restricting the Food and Drug Administration's (FDA's) control over dietary supplements. Unfortunately, colloidal silver products had previously qualified as dietary supplements in the FDA's original rulings and so became available for legal sale in the United States. Increased marketing on the Internet caused the sales of silver-containing medicinal products to grow rapidly. Realizing the problem, in 1999 the FDA amended the DSHEA specifically for colloidal silver products, stating "... All over-the-counter drug products containing colloidal silver ingredients or silver salts are not generally recognized as safe and effective and are misbranded.'' (4) Subsequently, the FDA and the Federal Trade Commission sent warning letters to the operators of many Web sites that market colloidal silver with drug-like claims (i.e., that their product diagnoses, treats, cures, or prevents disease). Despite these efforts, silver products remain widely available on the market today.

Several recent case reports of argyria from the use of silver-containing products have been described. Formulations associated with recent cases of argyria include topical nasal sprays for allergies, (5-7) silver-containing nutritional supplements, (8,9) homemade remedies containing silver, (10) silver therapies for diabetes, (11) and a colloidal silver preparation to treat arthritis. (12)

Silver formulations

Silver-containing products come in several different formulations. Colloidal silver is a suspension of submicroscopic silver particles in a liquid base. It is the most common formulation in silver-containing nasal sprays and is the most common form marketed on the Internet. Other common formulations include the topical antibiotic silver sulfadiazine and the topical cauterizing agent silver nitrate.

Silver-containing products are believed to produce their antimicrobial effect by reacting with and denaturing bacterial proteins, affecting the bacterial cell wall and cell membrane. (13) However, in 2004, van Hasselt et al conducted in vitro tests in which colloidal silver concentrations as high as 413 parts per million (ppm) showed no antimicrobial activity against a variety of bacteria. (14) These researchers question the validity of using silver-containing products as antimicrobials.

Silver and argyria

The adverse effects of silver-containing products depend on the cumulative dose, route and duration of exposure, and the general health of the exposed individual. Argyria can result in either generalized or localized discoloration of the skin, depending on the route of exposure. Generalized argyria requires a route of administration that allows silver to enter the bloodstream, for example via ingestion of silver products, use of silver nasal sprays, or intravenous administration. Localized argyria is caused by local exposure to silver, for example by silver jewelry or silver sulfadiazine cream.