Imiquimod

Water spray, dry chemical, carbon dioxide or foam as appropriate for surrounding fire and materials.

As with all fires, evacuate personnel to a safe area. Firefighters should use self-contained breathing equipment and protective clothing.

Imiquimod topical cream should be stored at 4-25 °C; freezing should be avoided.

Store in tight container as defined in the USP-NF. This material should be handled and stored per label instructions to ensure product integrity.

Wear approved respiratory protection, chemically compatible gloves and protective clothing. Wipe up spillage or collect spillage using a high efficiency vacuum cleaner. Avoid breathing dust. Place spillage in appropriately labeled container for disposal. Wash spill site.

SRP: Expired or waste pharmaceuticals shall carefully take into consideration applicable DEA, EPA, and FDA regulations. It is not appropriate to dispose by flushing the pharmaceutical down the toilet or discarding to trash. If possible return the pharmaceutical to the manufacturer for proper disposal being careful to properly label and securely package the material. Alternatively, the waste pharmaceutical shall be labeled, securely packaged and transported by a state licensed medical waste contractor to dispose by burial in a licensed hazardous or toxic waste landfill or incinerator.

Place material in a thick plastic hazardous waste disposal bag or leakproof container and label it CAUTION: HAZARDOUS CHEMICAL WASTE. Dispose of waste in accordance with all applicable Federal, State and local laws.

SRP: The scientific literature for the use of contact lenses by industrial workers is inconsistent. The benefits or detrimental effects of wearing contact lenses depend not only upon the substance, but also on factors including the form of the substance, characteristics and duration of the exposure, the uses of other eye protection equipment, and the hygiene of the lenses. However, there may be individual substances whose irritating or corrosive properties are such that the wearing of contact lenses would be harmful to the eye. In those specific cases, contact lenses should not be worn. In any event, the usual eye protection equipment should be worn even when contact lenses are in place.

As with all dry powders it is advisable to ground mechanical equipment in contact with dry material to dissipate the potential buildup of static electricity.

SRP: Local exhaust ventilation should be applied wherever there is an incidence of point source emissions or dispersion of regulated contaminants in the work area. Ventilation control of the contaminant as close to its point of generation is both the most economical and safest method to minimize personnel exposure to airborne contaminants. Ensure that the local ventilation moves the contaminant away from the worker.

As a general rule, when handling USP Reference Standards, avoid all contact and inhalation of dust, mists, and/or vapors associated with the material. Clean equipment and work surfaces with suitable detergent or solvent after use. After removing gloves, wash hands and other exposed skin thoroughly.

Avoid exposure to heat and moisture.

Airborne exposure should be controlled primarily by engineering controls such as general dilution ventilation, local exhaust ventilation, or process enclosure. Local exhaust ventilation is generally preferred to general exhaust because it can control the contaminant at its source, preventing dispersion into the work area. An industrial hygiene survey involving air monitoring may be used to determine the effectiveness of engineering controls. Effectiveness of engineering controls intended for use with highly potent materials should be assessed by use of nontoxic surrogate materials. Local exhaust ventilation such as a laboratory fume hood or other vented enclosure is recommended, particularly for grinding, crushing, weighing, or other dust-generating procedures.

Respiratory Protection: Where respirators are deemed necessary to reduce or control occupational exposures, use NIOSH-approved respiratory protection and have an effective respirator program in place. Gloves: Chemically compatible. For handling solutions, ensure that the glove material is protective against the solvent being used. Use handling practices that minimize direct hand contact. Employees who are sensitive to natural rubber (latex) should use nitrile or other synthetic nonlatex gloves. Use of powdered latex gloves should be avoided due to the risk of latex allergy. Eye Protection: Safety glasses with sideshields are recommended. Face shields or goggles may be required if splash potential exists or if corrosive materials are present. Approved eye protection (e.g., bearing the ANSI Z87 or CSA stamp) is preferred. Maintain eyewash facilities in the work area. Protective Clothing: For handling of laboratory scale quantities, a cloth lab coat is recommended. Where significant quantities are handled, work clothing may be necessary to prevent take-home contamination.

TERRESTRIAL FATE: Based on a classification scheme(1), an estimated Koc value of 1000(SRC), determined from a structure estimation method(2), indicates that imiquimod is expected to have moderate mobility in soil(SRC). Aromatic amines are expected to bind strongly to humus or organic matter in soils due to the high reactivity of the aromatic amino group(3,4), suggesting that mobility may be much lower in some soils(SRC). Volatilization of imiquimod from moist soil surfaces is not expected to be an important fate process(SRC) given an estimated Henry's Law constant of 8.3X10-12 atm-cu m/mole(SRC), using a fragment constant estimation method(5). Imiquimod is not expected to volatilize from dry soil surfaces(SRC) based upon an estimated vapor pressure of 7.8X10-9 mm Hg at 25 °C(SRC), determined from a fragment constant method(2). Biodegradation data in soil were not available(SRC, 2013).

AQUATIC FATE: Based on a classification scheme(1), an estimated Koc value of 1000(SRC), determined from a structure estimation method(2), indicates that imiquimod is expected to adsorb to suspended solids and sediment(SRC). Volatilization from water surfaces is not expected(3) based upon an estimated Henry's Law constant of 8.3X10-13 atm-cu m/mole(SRC), developed using a fragment constant estimation method(4). According to a classification scheme(5), an estimated BCF of 50(SRC), from an estimated log Kow of 3.06(6) and a regression-derived equation(2), suggests the potential for bioconcentration in aquatic organisms is moderate(SRC). Biodegradation data in water were not available(SRC, 2013).

ATMOSPHERIC FATE: According to a model of gas/particle partitioning of semivolatile organic compounds in the atmosphere(1), imiquimod, which has an estimated vapor pressure of 7.8X10-9 mm Hg at 25 °C(SRC), determined from a fragment constant method(2), is expected to exist solely in the particulate phase in the ambient atmosphere. Particulate-phase imiquimod may be removed from the air by wet and dry deposition(SRC). Imiquimod contains chromophores that absorb at wavelengths >290 nm(3) and, therefore, may be susceptible to direct photolysis by sunlight(SRC).

Reported side effects of 5% imiquimod cream, when used to treat external anogenital warts, are often mild and include erythema, edema, erosion, excoriation, induration, or scabbing. Patients have also reported pain, pruritus, and irritation at the site of application or local cutaneous edema or erythema with the use of topical 2.5% or 3.75% imiquimod creams to treat external anogenital warts. When used to treat actinic keratoses, reported local adverse effects of imiquimod cream include erythema, flaking, scabbing, edema, weeping, and erosion, but the presence of these reactions correlates with improved lesion clearance. Less common systemic adverse effects when 5% imiquimod cream was applied to the scalp, face, or upper extremity to treat actinic keratosis included flu-like symptoms, headache, fever, anorexia, somnolence, fatigue, nausea, myalgia, and diarrhea. When applied for the treatment of superficial basal cell carcinoma, adverse effects include pruritus, burning, and pain at the application site and uncommon upper respiratory tract infections, back pain, or sinusitis. Application site reactions usually do not result in treatment withdrawal due to their frequent lack of severity.

While most side effects of topical imiquimod use are mild, there are reports of severe local or systemic adverse effects associated with topical imiquimod use, in which case the prescriber may need to halt treatment. For patients with autoimmune conditions, the application of imiquimod over large areas of the body should prompt caution, given the potential for a systemic immune response.

Using a structure estimation method based on molecular connectivity indices(1), the Koc of imiquimod can be estimated to be 1000(SRC). According to a classification scheme(2), this estimated Koc value suggests that imiguimod is expected to have low mobility in soil. Aromatic amines are expected to bind strongly to humus or organic matter in soils due to the high reactivity of the aromatic amino group(3,4), suggesting that mobility may be much lower in some soils(SRC).

/SIGNS AND SYMPTOMS/ Topical overdosing of Aldara Cream could result in an increased incidence of severe local skin reactions and may increase the risk for systemic reactions. The most clinically serious adverse event reported following multiple oral imiquimod doses of >200 mg (equivalent to imiquimod content of >16 packets) was hypotension, which resolved following oral or intravenous fluid administration.

/CASE REPORTS/ Erosive pustular dermatosis of the scalp (EPDS) is a rare condition characterized by sterile pustules, erosions, and crusted lesions on the scalp of elderly patients. This inflammatory disorder has an unknown origin and it could develop into areas of alopecia that tend to be atrophic. An 84-year-old Caucasian man presented with a several months history of painful erythematous erosions and crusts on his scalp. The lesions appeared after treatment with imiquimod cream for actinic keratoses. Previous therapies included topical antibiotics and topical steroids. Physical examination revealed the presence of extensive erosions and crusts on the scalp, with minute pustules on the sides. The clinical features and the medical history led us to the diagnosis of EPDS. Treatment with systemic steroid was administered with improvement observed after ten days. The clinical manifestations of EPDS completely resolved after 2 months, without clinical relapses.

/CASE REPORTS/ Imiquimod is a topical immune response modifier used to treat anogenital warts. Although considered a safe drug, mild to moderate local and systemic side-effects may occasionally occur. /The researchers/ report three cases of local and systemic adverse effects related to imiquimod, including one case that mimicked meningitis, which promptly resolved with drug cessation.

/CASE REPORTS/ A 44-year-old man who was previously diagnosed with actinic cheilitis was prescribed imiquimod cream 5%, which resulted in thick hemorrhagic crusting of the lower lip after 4 applications. He subsequently noted the development of lichen planus lesions on his arms and legs for the first time in 15 years following imiquimod use. On follow-up he also was noted to have characteristic Wickham striae on his lower lip. Lichen planus is an autoimmune inflammatory condition in which autoreactive T lymphocytes attack keratinocytes. The mechanism of action for imiquimod is upregulation of IFN-alpha and IFN-beta. Treatment with clobetasol cream 0.05% led to resolution of his lichen planus lesions.

For more Human Toxicity Excerpts (Complete) data for Imiquimod (6 total), please visit the HSDB record page.

An estimated BCF of 50 was calculated in fish for imiquimod(SRC), using an estimated log Kow of 3.06(1) and a regression-derived equation(2). According to a classification scheme(3), this BCF suggests the potential for bioconcentration in aquatic organisms is moderate(SRC).

The Henry's Law constant for imiquimod is estimated as 8.3X10-13 atm-cu m/mole(SRC) using a fragment constant estimation method(1). This Henry's Law constant indicates that imiquimod is expected to be essentially nonvolatile from water and moist soil surfaces(2). Imiquimod is not expected to volatilize from dry soil surfaces(SRC) based upon an estimated vapor pressure of 7.8X10-9 mm Hg(SRC), determined from a fragment constant method(3).

/LABORATORY ANIMALS: Chronic Exposure or Carcinogenicity/ In a 52-week dermal photoco-carcinogenicity study, the median time to onset of skin tumor formation was decreased in hairless mice following chronic topical dosing (3X/week; 40 weeks of treatment followed by 12 weeks of observation) with concurrent exposure to UV radiation (5 days per week) with the Aldara Cream vehicle alone. No additional effect on tumor development beyond the vehicle effect was noted with the addition of the active ingredient, imiquimod, to the vehicle cream.

/LABORATORY ANIMALS: Chronic Exposure or Carcinogenicity/ In a dermal mouse carcinogenicity study, imiquimod cream (up to 5 mg/kg/application imiquimod or 0.3% imiquimod cream) was applied to the backs of mice 3X/week for 24 months. A statistically significant increase in the incidence of liver adenomas and carcinomas was noted in high dose male mice compared to control male mice (251X MRHD based on weekly AUC comparisons). An increased number of skin papillomas was observed in vehicle cream control group animals at the treated site only. The quantitative composition of the vehicle cream used in the dermal mouse carcinogenicity study is the same as the vehicle cream used for Aldara Cream, minus the active moiety (imiquimod).

/LABORATORY ANIMALS: Chronic Exposure or Carcinogenicity/ In an oral (gavage) rat carcinogenicity study, imiquimod was administered to Wistar rats on a 2X/week (up to 6 mg/kg/day) or daily (3 mg/kg/day) dosing schedule for 24 months. No treatment related tumors were noted in the oral rat carcinogenicity study up to the highest doses tested in this study of 6 mg/kg administered 2X/week in female rats (87X MRHD based on weekly AUC comparisons), 4 mg/kg administered 2X/week in male rats (75X MRHD based on weekly AUC comparisons) or 3 mg/kg administered 7X/week to male and female rats (153X MRHD based on weekly AUC comparisons).

/LABORATORY ANIMALS: Chronic Exposure or Carcinogenicity/ /The researchers/ have provided evidence for a multifaceted antitumor-function of the Toll-like receptor 7 (TLR7) agonist imiquimod, which rapidly recruits plasmacytoid dendritic cells and possibly other immune cells into tumors by inducing the secretion of CCL2 by dermal cells. Imiquimod induces pDC maturation and their conversion into cytolytic killer cells, which are capable of eliminating tumors independently from the adaptive immune system.

For more Non-Human Toxicity Excerpts (Complete) data for Imiquimod (9 total), please visit the HSDB record page.

Imiquimod cream should be used with caution in organ transplant patients. Consideration should be given to balancing the benefit of imiquimod treatment for these patients with the risk associated with the possibility of organ rejection or graft-versus-host disease.

Imiquimod should be used with caution in patients with reduced hematologic reserve.

Imiquimod cream should be used with caution in patients with autoimmune conditions. Consideration should be given to balancing the benefit of imiquimod treatment for these patients with the risk associated with a possible worsening of their autoimmune conditions.

Imiquimod is not expected to undergo hydrolysis in the environment due to the lack of functional groups that hydrolyze under environmental conditions(1). Imiquimod contains chromophores that absorb at wavelengths >290 nm(1) and, therefore, may be susceptible to direct photolysis by sunlight(SRC).

The Approved Drug Products with Therapeutic Equivalence Evaluations identifies currently marketed prescription drug products, including imiquimod, approved on the basis of safety and effectiveness by FDA under sections 505 of the Federal Food, Drug, and Cosmetic Act.

MEDICATION

Adjuvants, Immunologic; Antineoplastic Agents

Use (kg; approx.) in Germany (2009): >10

For topical use, imiquimod is commercially /available/ as a 5% cream. Each gram of the cream contains 50 mg of imiquimod in an off-white, oil-in-water vanishing cream base. Imiquimod topical cream contains methylparaben and propylparaben as preservatives.

Topical: Cream 5%, Aldara (Graceway).

Zyclara, Beselna