|Trade names||Aldara originally. Many brands available.|
|ATC code||D06BB10 (WHO)|
|Biological half-life||30 hours (topical dose), 2 hours (subcutaneous dose)|
|Chemical and physical data|
|Molar mass||240.304 g/mol|
|3D model (Jmol)||Interactive image|
Imiquimod (INN) is a prescription medication that acts as an immune response modifier and is used to treat genital warts, superficial basal cell carcinoma, and actinic keratosis. Scientists at 3M's pharmaceuticals division discovered the drug and 3M obtained the first FDA approval in 1997 under the brand Aldara. As of 2015 imiquimod is generic and is available worldwide under many brands.
Side effects include local inflammatory reactions like blisters, a burning sensation, skin redness, dry skin, itching, skin breakdown, skin crusting or scabbing, skin drainage, skin flaking or scaling, skin ulceration, sores, swelling, as well as systemic reactions like fever, "flu-like" symptoms, headache, and tiredness.
Mechanism of action
It is known that imiquimod signals to the innate arm of the immune system through the toll-like receptor 7 (TLR7), commonly involved in pathogen recognition. Cells activated by imiquimod via TLR-7 secrete cytokines (primarily interferon-α (IFN-α), interleukin-6 (IL-6), and tumor necrosis factor-α (TNF-α)). There is evidence that imiquimod, when applied to skin, can lead to the activation of Langerhans cells, which subsequently migrate to local lymph nodes to activate the adaptive immune system. Other cell types activated by imiquimod include natural killer cells, macrophages and B-lymphocytes. Overall imiquimod acts on several levels, which appear to synergistically underlie the profound antitumoral activity of the compound.
Scientists at 3M's pharmaceutical division discovered imiquimod as part of a program to discover inhibitors of herpes virus replication based on a known adenine derivative.:369–372 3M obtained the first FDA approval for it in 1997 as a treatment for external genital and perianal warts under the brand, "Aldara". In 2004 3M obtained FDA approval to market imiquimod as a treatment for superficial basal cell carcinoma.
In 2006, 3M sold its pharmaceutical business in the Americas to Graceway Pharmaceuticals, its European pharmaceutical business to Meda AB, and its pharmaceutical business in other territories to two private equity firms.
Graceway declared bankruptcy in 2011 after the expiration of the patents on imiquimod, and its assets, including the rights to imiquimod branding and approvals in the Americas, were purchased by Medicis Pharmaceutical.
As of 2015, imiquimod is generic and is available worldwide under many brands.
Imiquimod has been tested for treatment of molluscum contagiosum. Two large randomized controlled trials, however, found no evidence of effectiveness of imiquimod in treating children with molluscum contagiosum, and concerning adverse effects were also noted.
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