Determination of the Area of Skin Capable of Being Covered by the Application of 250 mg of 5% Imiquimod Cream

Background. Five percent imiquimod cream is FDA‐approved for the treatment of genital and perianal warts and actinic Keratosis. The manufacturer recommends that a single sachet containing 250 mg of 5% imiquimod cream (12.5 mg of imiquimod) is adequate for a single use and is sufficient to cover a wart area of up to 20 cm2. Objective. To determine the maximal area of skin that can be evenly covered by 250 mg of 5% imiquimod cream that is contained in one single‐use sachet. Methods. The contents of one 250‐mg single‐use sachet of 5% imiquimod cream were mixed with less than 1 mg of fluorescein sodium. The cream was applied evenly onto the abdomen of two Yorkshire female pigs and onto the medial and lateral aspects of the upper left arm of a human subject. The area of application was then measured. Results. The average area obtained on the pig skin was 196 cm2. The area covered on the human subject was 386 cm2. Conclusion. We have found that one sachet of 250 mg of 5% imiquimod cream can be applied to an area of skin up to 386 cm2. In light of the increasing use of 5% imiquimod cream in the treatment of cutaneous diseases, such as actinic keratoses, which affect larger areas of skin than genital warts, a more efficient use of 5% imiquimod cream may make this medication a more cost‐effective treatment modality.