Imiquimod

Examples

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Brand Name	Chemical Name
Aldara	imiquimod (5% and 1% cream)

How It Works

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Imiquimod is thought to work by helping the body's immune system produce interferon and similar substances that attack abnormal cells, viruses, and cancerous cells.

Imiquimod is a cream available by prescription: it can be applied at home. Your health professional will show you how to apply imiquimod.

Why It Is Used

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Imiquimod may be the medicine treatment your health professional recommends first for external genital warts. It may shrink the warts.

Imiquimod is approved to treat genital warts, actinic keratosis, and superficial basal cell carcinoma.

Imiquimod can be used for difficult-to-treat common warts.

It is not known whether imiquimod is safe to use during pregnancy or on children younger than 12. In the United States, the U.S. Food and Drug Administration (FDA) has approved imiquimod for those age 12 and older.

How Well It Works

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Genital warts

Studies report:

• Many genital warts go away within 4 months of treatment.¹
• Imiquimod 5% cream is more effective than 1% cream for genital warts.²

Most recurrences happen within 2 weeks of completed treatment.

Basal cell carcinoma

Studies show that more than 75% of superficial basal cell carcinomas cleared when imiquimod cream was applied. Imiquimod may prove to be beneficial in treating large, superficial basal cell carcinomas on the trunk of the body, where surgical treatment can cause severe scarring.³

Common warts

Whether imiquimod is an effective treatment for common warts is not yet known.

Side Effects

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Side effects of imiquimod, which are common but usually mild, include:¹

• Skin redness.
• Flaking of the skin.
• Swelling.
• Scabs.
• Itching.
• Burning.
• Lightening of skin color.

Less common side effects include:

• Headache.
• Flu-like symptoms.
• Muscle pain.

See Drug Reference for a full list of side effects. (Drug Reference is not available in all systems.)

What To Think About

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Wash your hands after applying imiquimod cream, because it may cause skin irritation.

The cost of imiquimod, which may not be covered by insurance, can be very expensive for the length of treatment.

The benefits and effectiveness of each type of treatment need to be compared with the side effects and cost. Discuss this with your health professional.

Genital warts

Genital warts may go away on their own. Treating genital warts may not cure a human papillomavirus (HPV) infection. The virus may remain in the body in an inactive state after warts are removed. A person treated for genital warts may still be able to spread the infection. Condoms may help reduce the risk of HPV infection.

Avoid sexual contact while you are using imiquimod cream for genital warts. The cream may weaken condoms and diaphragms. It also may irritate your partner's skin or may rub off during sex.

Basal cell carcinoma

Imiquimod is usually used to treat basal cell carcinomas when surgical methods cannot be used.

Common warts

Imiquimod may be used on warts that are resistant to other treatments. It is generally used when other treatments have failed.

Complete the new medication information form (PDF) (What is a PDF document?) to help you understand this medication.

References

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Citations

1. Buck HW (2005). Genital warts. Online version of Clinical Evidence (14): 1–13.

2. Wiley DJ, et al. (2002). External genital warts: Diagnosis, treatment, and prevention. Clinical Infectious Diseases, 35(Suppl 2): S210–S224.

3. U.S. Food and Drug Administration (2004). Aldara (imiquimod) for superficial basal cell carcinoma. Available online: http://www.fda.gov/bbs/topics/news/2004/NEW01088.html.

Credits

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Author	Robin Parks, MS
Editor	Kathleen M. Ariss, MS
Associate Editor	Pat Truman
Primary Medical Reviewer	Joy Melnikow, MD, MPH - Family Medicine
Specialist Medical Reviewer	Jeanne Marrazzo, MD, MPH - Infectious Disease
Last Updated	August 17, 2006