May 7, 2009 (United Press International) -- The U.S. Food and Drug Administration says it will require makers of two prescription testosterone gel products to add boxed warnings to their labels.

The federal agency said it is requiring the action after receiving reports of adverse effects in children who were inadvertently exposed to testosterone through contact with another person being treated with the topical products -- AndroGel and Testim.

The gels are approved for use in men who either no longer produce testosterone or produce it in very low amounts. Precautions on the current labels instruct users to wash their hands after using the product and to cover the treated skin with clothing.

Despite currently labeled precautions, as of Dec. 1 the FDA had received reports of eight cases of secondary exposure to testosterone in children ranging in age from nine months to five years.

Since that time, additional reports of secondary exposure have been received by the FDA and are presently under review, including inappropriate enlargement of genitalia, premature development of pubic hair and increased libido and aggressive behavior.

AndroGel is manufactured by Solvay Pharmaceuticals, and Testim is made by Auxilium Pharmaceuticals. (NASDAQ:AUXL)