Imiquimod (Aldara) is a drug that stimulates the immune system to produce interferon alfa, a natural chemical that helps the body to fight viruses. It has been approved in Europe and the United States for the treatment of warts and a type of cancer called small superficial basal cell carcinoma. It is available as capsules and a cream.

The cream is applied three times a week for around eight hours, with most patients showing an improvement in symptoms after 16 weeks. The safety of imiquimod cream has not been demonstrated in immunosuppressed patients beyond 16 weeks.

A cream formulation of imiquimod has been studied as a treatment for warts caused by the human papilloma virus. In HIV-negative people, imiquimod has been shown to clear up warts^[1]. Despite some concerns that immunocompromised patients may not benefit from imiquimod treatment, studies have also suggested that topical imiquimod is an effective treatment for warts and pre-cancerous changes called neoplasia in HIV-infected people, including those taking antiretroviral therapy^[2][3][4][5]. It may also prevent the recurrence of anal warts after surgical removal, by reducing viral levels in the lining of the anal canal^[6].

Several reports suggest that imiquimod cream may also be effective for HIV-related molluscum contagiosum^[7][8][9].

Imiquimod is also being investigated for several HIV-associated conditions and for HIV infection itself. A pilot study found that imiquimod capsules can produce significant increases in CD4 cell counts^[10].

Side-effects of imiquimod cream include redness, swelling, hardening under the skin, wearing away of the top skin layers, blisters, ulcers, scabbing, pain, burning and itching. Imiquimod capsules have also caused symptoms such as tiredness, temperature, muscle aches, joint pain and malaise, which are thought to be a result of the body producing interferon. These influenza-like side-effects are thought to be unlikely with the cream formulation.

Patients using the cream to treat warts under the foreskin need to wash under the foreskin every day, to prevent tightening of the foreskin.