Imiquimod 5%Creams /Imiquimod is a synthetic agent with an immune response modifying activity. As an immune response modifier (IRM), imiquimod stimulates cytokine production, especially interferon production, and exhibits antitumor activity, particularly against cutaneous cancers. Imiquimod’s proapoptotic activity appears to be related to Bcl-2 overexpression in susceptible tumor cells.
Imiquimod is an immune response modifier that acts as a toll-like receptor 7 agonists. Imiquimod is commonly used topically to treat warts on the skin of the genital and anal areas. Imiquimod does not cure warts, and new warts may appear during treatment. Imiquimod does not fight the viruses that cause warts directly, however, it does help to relieve and control wart production. imiquimod is also used to treat a skin condition of the face and scalp called actinic keratoses and certain types of skin cancer called superficial basal cell carcinoma.
Imiquimod is an imidazoquinoline fused carrying isobutyl and amino substituents at N-1 and C-4 respectively. A prescription medication, it acts as an immune response modifier and is used to treat genital warts, superficial basal cell carcinoma, and actinic keratosis. It has a role as an antineoplastic agent and an interferon inducer.
Mechanism of Action of Imiquimod
Imiquimod’s mechanism of action is via stimulation of innate and acquired immune responses, which ultimately leads to inflammatory cell infiltration within the field of drug application followed by apoptosis of diseased tissue. Imiquimod does not have direct antiviral activity. Studies of mice show that imiquimod may induce cytokines, including interferon-alpha (IFNA) as well as several IFNA genes (IFNA1, IFNA2, IFNA5, IFNA6, and IFNA8) as well as the IFNB gene. Imiquimod also induced the expression of interleukin (IL)-6, IL-8, and tumor necrosis factor-alpha genes. In the treatment of basal cell carcinoma, Imiquimod appears to act as a toll-like receptor-7 agonist and is thought to exert its anti-tumor effect via modification of the immune response and stimulation of apoptosis in BCC cells. In treating basal cell carcinoma it may increase the infiltration of lymphocytes, dendritic cells, and macrophages into the tumor lesion.
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Imiquimod and resiquimod represent Toll-like receptor (TLR) 7 and 8 agonists, which emerged as attractive candidates for tumor therapy. To elucidate immune cells, which mainly contribute to TLR7 8-mediated antitumoral activity, /the researchers investigated the impact of imiquimod and resiquimod on native human 6-sulfo LacNAc (slan) dendritic cells (DCs). The researchers found that both TLR7 8 agonists significantly improve the release of various proinflammatory cytokines by slanDCs and promote their tumor-directed cytotoxic activity. Furthermore, resiquimod efficiently augmented the ability of plants to stimulate T cells and natural killer cells. These results indicate that imiquimod and resiquimod trigger various immunostimulatory properties of plants, which may contribute to their antitumor effects
Indications of Imiquimod
- For the topical treatment of clinically typical, nonhyperkeratotic, nonhypertrophic actinic keratoses on the face or scalp in immunocompetent adults. Also indicated for the treatment of external genital and perianal warts condyloma acuminate in individuals 12 years old and above.
- Imiquimod cream is indicated for the topical treatment of external genital and perianal warts (condylomata acuminate) in adults.- Small superficial basal cell carcinomas (ABCs) in adults.
- Clinically typical, nonhyperkeratotic, nonhypertrophic actinic keratoses (AKs) on the face or scalp in immunocompetent adult patients when size or number of lesions limit the efficacy and/or acceptability of cryotherapy and other topical treatment options are contraindicated or less appropriate.
- Imiquimod is a patient-applied cream prescribed to treat genital warts, Bowen’s disease (squamous cell carcinoma in situ), and, secondary to surgery, for basal cell carcinoma, as well as actinic keratosis.
- Keratosis
- Basal Cell Carcinoma
- Human Papilloma Virus
- Condylomata Acuminata
- Molluscum Contagiosum
- For the topical treatment of clinically typical visible or palpable actinic keratoses of the full face or balding scalp in immunocompetent patients
Therapeutic Uses of Imiquimod
Adjuvants, Immunologic; Antineoplastic Agents
- Imiquimod is used topically for the treatment of clinically typical, nonhyperkeratotic, nonhypertrophic actinic keratosis on the face or scalp in immunocompetent adults; treatment of biopsy-confirmed, primary superficial basal cell carcinoma in immunocompetent adults; and treatment of external genital and perianal exophytic warts (condylomata acuminate) caused by human papillomavirus (HPV).
- Topical imiquimod has been effective when used in a limited number of adults and children for the treatment of molluscum contagiosum.
- Imiquimod 5% cream has been used for the topical treatment of external genital and perianal HPV warts in a limited number of adults with human immunodeficiency virus (HIV) infection; however, the response rate appears to be lower in these individuals than in those who are not HIV infected.
- Imiquimod is under investigation for the treatment of Bowen’s disease. It has also bee tried in lentigo maligna and other forms of localized or in-situ melanoma, and there are also reports of investigational use in the management of metastatic melanoma and in anal and vulvar intraepithelial neoplasia.
- Evidence from small studies, suggests that topical imiquimod 5 or 7% cream, in combination with parenteral meglumine antimonate may be of use in the management of cutaneous leishmaniasis.
Contraindications of Imiquimod
- a reduction in the body’s resistance to infection
- disease in which the body has an immune response against itself
- sunburn
- increased sensitivity of the skin to the sun
- graft versus host disease
- Allergies to Imiquimod
Dosage of Imiquimod
Strengths: 5%; 3.75%; 2.5%
Keratosis
- 2.5% and 3.75% cream – Apply a thin film once a day before bedtime to the affected area (either entire face or balding scalp)
- Treatment should continue for two 2-week treatment cycles separated by a 2-week no-treatment period.
- The cream should be applied as a thin film to the entire treatment area and rubbed in until it is no longer visible.
- Up to 2 packets or 2 pumps actuation may be applied per application.
- To be left on the skin for about 8 hours, after which, to be removed with mild soap and water.
- 5% cream – Apply topically to the affected area on the face or scalp (but not both concurrently) 2 times per week for a full 16 weeks
Condylomata Acuminata
- 3.75% cream – Apply a thin layer once a day to the external genital/perianal warts until total clearance or up to 8 weeks
- Up to 1 packet or 1 full actuation of the pump of cream may be used at the treatment site for each application.
- To be applied prior to normal sleeping hours and left on the skin for about 8 hours, then removed by washing the area with mild soap and water.
- Nonocclusive dressings such as cotton gauze or cotton underwear may be used in the management of skin reaction
- 5% cream – Apply topically to external genital/perianal warts 3 times per week
Basal Cell Carcinoma
- 5% cream: Apply topically to a biopsy-confirmed superficial basal cell carcinoma 5 times per week for a full 6 weeks
Condylomata Acuminata
12 years or older
- 3.75% cream: Apply a thin layer once a day to the external genital/perianal warts until total clearance or up to 8 weeks
- Up to 1 packet of cream maybe used at the treatment site for each application.
- To be applied prior to normal sleeping hours and left on the skin for about 8 hours, then removed by washing the area with mild soap and water.
12 years or older
- 5% cream: Apply topically to external genital/perianal warts 3 times per week
Side Effects of Imiquimod
Most Common
- Abdominal or stomach pain
- ankle, knee, or great toe joint pain
- itching in the genital or other skin areas
- open sores or scabs on the skin
- pain or tenderness around the eyes and cheekbones
- redness of the skin (severe)
- bladder pain
- bloody or cloudy urine
- blurred vision
- chest pain
- cold flu-like symptoms
- difficult, burning, or painful urination
Common
- Burning or stinging of the skin (mild)
- flaking of the skin
- mild headache
- pain, soreness, or tenderness of the skin (mild)
- rash
- redness of the skin (mild)
- swelling at place of application
- blistering on skin
- burning or stinging of skin (mild)
- diarrhea
- dizziness
- fatigue
- flaking or peeling of skin
- hair loss
- hardening of skin
- headache
- heartburn
- lightened or darkened skin colour where skin is treated
- nausea
- pain at the site of application
- redness of skin (mild)
- scabbing, crusted skin
- skin itching
- swelling of skin (mild)
- vomiting
Rare
- joint stiffness or swelling
- lower back or side pain
- lump in the abdomen or stomach
- nervousness
- persistent non-healing sore
- pink growth on the skin
- pounding in the ears
- a reddish patch or irritated area
- severe headache
- shiny bump on the skin
- slow or fast heartbeat
- swollen, painful, or tender lymph glands in the neck, armpit, or groin
- white, yellow or waxy scar-like area
- any sign or symptom in the treatment area that makes daily activity difficult or impossible
- painful, swollen joints
- rash
- symptoms of an infection (e.g., coughing, fever, runny nose, sore throat, swollen glands)
- chest pain
- signs of an allergic reaction (such as difficulty breathing, hives, or swelling of the face or throat)
Drug Interactions of Imiquimod 5%Creams
Imiquimod may interact with following drugs, supplements, & may change the efficacy of drugs
- aminolevulinic acid
- aminolevulinic acid topical
- methoxsalen
- methyl aminolevulinate topical
- corticosteroids (e.g., prednisone)
- denosumab
- echinacea
- leflunomide
- live vaccines (e.g., BCG, yellow fever)
- medications that suppress the immune system (such as medications for cancer or organ transplants, e.g., tacrolimus, cyclosporine, methotrexate)
- natalizumab
- echinacea
- leflunomide
- live vaccines (e.g., BCG, yellow fever)
- medications that suppress the immune system (such as medications for cancer or organ transplants, e.g., tacrolimus, cyclosporine, methotrexate)
- natalizumab
- pimecrolimus
- other medications applied to the skin
Pregnancy Category of Imiquimod 5%Creams
FDA Pregnancy Category – C
Pregnancy
This medication should not be used during pregnancy unless the benefits outweigh the risks. If you become pregnant while taking this medication, contact your doctor immediately.
Breast-feeding
It is not known if imiquimod passes into breast milk. If you are a breast-feeding mother and are taking this medication, it may affect your baby. Talk to your doctor about whether you should continue breast-feeding. The safety and effectiveness of using this medication have not been established for children less than 18 years of age.
References
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