ATC Class:D11AX13
VA Class:DE900
Monobenzone, the monobenzyl ether of hydroquinone, is a depigmenting agent.
Monobenzone is applied topically to permanently depigment normal skin surrounding vitiliginous lesions in patients with disseminated (greater than 50% of body surface area) idiopathic vitiligo. Monobenzone is not recommended for use in freckling; hyperpigmentation caused by photosensitization following the use of certain perfumes (berlock dermatitis); chloasma; or hyperpigmentation resulting from inflammation of the skin. The drug is not effective for the treatment of cafe-au-lait spots, pigmented nevi, malignant melanoma, or pigmentation resulting from pigments other than melanin (e.g., bile, silver, or artificial pigments).
Monobenzone is applied topically in the form of a 20% cream. The drug should not be administered orally. To depigment normal skin surrounding vitiliginous lesions, a thin layer of monobenzone cream should be applied uniformly and rubbed into the pigmented area 2-3 times daily. Prolonged exposure to sunlight should be avoided during treatment with the drug or a sunscreen should be used. Depigmentation is usually accomplished after 1-4 months of monobenzone treatment; if satisfactory results are not obtained after 4 months of treatment, the drug should be discontinued. When the desired degree of depigmentation is obtained, monobenzone should be applied as often as needed to maintain depigmentation (usually only 2 times weekly).
Mild, transient skin irritation and sensitization, including erythematous and eczematous reactions, have occurred following topical application of monobenzone. Although these reactions are usually transient, treatment with monobenzone should be discontinued if irritation, a burning sensation, or dermatitis occurs. Areas of normal skin distant to the site of monobenzone application frequently have become depigmented by the drug and irregular, excessive, unsightly, and frequently permanent depigmentation has occurred.
Precautions and Contraindications
Monobenzone is a potent depigmenting agent and is not a cosmetic skin bleach. Use of the drug is contraindicated in any condition other than disseminated vitiligo. In addition, because monobenzone frequently causes irreversible depigmentation, it must not be used as a substitute for hydroquinone.
Information on the acute toxicity of monobenzone is limited, but oral doses of 50-500 mg/kg are reportedly fatal.
Following topical application in animals, monobenzone increases the excretion of melanin from melanocytes; the same action is thought to be responsible for the depigmenting effect of the drug in humans. Some pharmacologists believe that monobenzone may also prevent melanin production. In some patients, the drug causes destruction of melanocytes and permanent depigmentation. Depigmentation is erratic and may take 1-4 months to occur while existing melanin is lost with the normal sloughing of the stratum corneum and excretion of new melanin is increased by monobenzone. Hyperpigmented skin appears to fade more rapidly than does normal skin, and exposure to sunlight reduces the depigmenting effect of the drug.
Information on the absorption, distribution, metabolism, and excretion of monobenzone is not available.
Monobenzone is the monobenzyl ether of hydroquinone. Monobenzone occurs as a white, almost tasteless, crystalline powder and is soluble in alcohol and practically insoluble in water.
Monobenzone cream should be stored in tight containers; exposure to temperatures exceeding 30°C should be avoided.
Excipients in commercially available drug preparations may have clinically important effects in some individuals; consult specific product labeling for details.
Please refer to the ASHP Drug Shortages Resource Center for information on shortages of one or more of these preparations.