Aldara for the Treatment of Nonmelanoma Skin Cancers

How Does it Work? What Are its Side Effects?

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Basal cell carcinoma (BCC) is the most common skin cancer worldwide, but it is curable if caught early. Common treatments include simple excision (removal) of the lesion, curettage and electrodesiccation (scraping and cauterizing),  Mohs surgery (a more complex surgical procedure), and topical (skin) creams such as fluorouracil and Aldara (imiquimod). If your doctor has prescribed Aldara, this introduction will arm you with the key information you need to effectively and safely treat your BCC.

Note that this information may not cover all possible precautions, interactions or adverse effects for these drugs. If you have any questions about the drugs you are taking, be sure to check with your healthcare professional.

Other Names (United States)

imiquimod (generic)


July 2004

Description of Aldara

Imiquimod is a skin-use only (topical) prescription medicine used to treat superficial basal cell carcinoma in adults with normal immune systems. It is used when surgical methods of removing the cancer are not appropriate — for example, in the case of multiple tumors on the face. It is also used to treat certain types of actinic keratosis (also called solar keratosis, a potential precursor to squamous cell skin cancer) on the face and scalp of adults with normal immune systems. Imiquimod cream activates your body's own immune system via a molecule called toll-like receptor 7 (TLR7), which in turn activates interferon-alpha to fight the cancerous cells.

Evidence for the Effectiveness of Aldara

The approval of imiquimod was based on two clinical trials involving 364 patients with primary superficial basal cell carcinomas. In the studies, the carcinomas cleared in 75% of patients treated with imiquimod cream compared with 2% in the placebo group. Of the patients successfully treated with imiquimod, almost 80% remained cancer-free after two years.

In addition, from a healthcare policy perspective, studies have shown that the use of imiquimod is more cost-effective than surgical interventions among patients with superficial BCC. Research is ongoing to learn about imiquimod's effectiveness in other types of BCC (such as the nodular subtype), as well as in melanoma (the lentigo maligna subtype), squamous cell carcinoma, cutaneous T-cell lymphoma, and other skin conditions, such as scars and warts.

Usage of Aldara

Imiquimod is a topical (skin only) cream. To treat BCC, imiquimod cream is usually used once a day, 5 days a week. It should be left on the skin for about 8 hours, so leaving it on overnight is a common strategy. Do not cover the treated site with bandages or other closed dressings. After the 8 hours have passed, the treated area should be washed with mild soap and water. Treatment should continue for a full 6 weeks, even if the BCC appears to be gone unless you are told otherwise by your dermatologist. Remember that imiquimod is for skin use only. Do not take by mouth or use in or near your eyes, lips or nostrils. Do not allow to enter open wounds, since more severe side effects may result.

Potential Side Effects of Aldara

The most common side effect of imiquimod is a skin reaction in the application area, which occurs in about one-third of patients.

Specifically, you may experience:

  • Redness
  • Swelling
  • A sore, blister or ulcer
  • Skin that becomes hard or thickened
  • Changes in skin color that do not always go away
  • Skin peeling
  • Scabbing and crusting
  • Itching
  • Burning

The area being treated is likely to look worse before it looks better. Skin reactions may be of such intensity that you could require rest periods from treatment. The treatment and surrounding areas may lighten or darken after treatment with this medicine, and this change may be permanent in some patients. For best results with imiquimod, follow your dermatologist's instructions closely.

Other potential side effects of imiquimod include headache, back pain, muscle aches, tiredness, flu-like symptoms, swollen lymph nodes, diarrhea and fungal infections.

If the reactions seem severe, if either skin breaks down or sores develop during the first week of treatment, if flu-like symptoms develop, or if you begin to not feel well at any time, contact your healthcare provider.

When using imiquimod for actinic keratosis or superficial basal cell carcinoma, exposure to sunlight (including sunlamps) should be avoided or minimized, because you will be more susceptible to sunburn. Use protective clothing, such as a hat, when using imiquimod.


Tell your healthcare provider about all of your medical conditions, including if you:

  • are pregnant or planning to become pregnant (it is not known if imiquimod can harm your unborn baby)
  • are breastfeeding (it is not known if imiquimod passes into your milk and if it can harm your baby)
  • are taking other medicines, including prescription and non-prescription medicines, vitamins and herbal supplements
  • are taking other treatments for superficial basal cell carcinoma, actinic keratosis, genital/anal warts, or any other skin condition (imiquimod should not be used until your skin has healed from other treatments)
  • have psoriasis (imiquimod has the potential to worsen inflammatory skin conditions, such as psoriasis)


"Aldara prescribing information." Graceway Pharmaceuticals.

Karve SJ, Feldman SR, Yentzer BA, Pearce DJ, Balkrishnan R. "Imiquimod: a review of basal cell carcinoma treatments." J Drugs Dermatol. 2008 7(11):1044-51.

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