Valchlor (mechlorethamine HCl)

Dosage of mechlorethamine hydrochloride gel is expressed in terms of mechlorethamine.

For the topical treatment of cutaneous lesions in patients with early (stage IA and IB) mycosis fungoides-type cutaneous T-cell lymphoma (CTCL), a thin film of mechlorethamine 0.016% gel should be applied to affected areas of the skin once daily. If any skin ulceration or blistering or moderately severe or severe dermatitis (i.e., marked erythema with edema) occurs, treatment with mechlorethamine gel should be interrupted. Upon improvement, treatment may be resumed with a reduced frequency of once every 3 days. If reintroduction of treatment is tolerated for at least one week, the application frequency may be increased to every other day for at least one week and then to once daily if tolerated.

When extemporaneously prepared topical solutions and ointments have been used for the treatment of cutaneous lesions of mycosis fungoides-type CTCL, the concentration of mechlorethamine hydrochloride, frequency of application, and duration of treatment have been based on the dermatologic response and tolerance of the patient. The usual concentration of mechlorethamine hydrochloride used in ointment preparations is 0.01 or 0.02%; lower concentrations may be used initially in patients with dermatitis or a history of hypersensitivity reactions to the topically applied drug, and higher concentrations may be used in patients with extensive or resistant lesions.

Applications of mechlorethamine generally are repeated once daily until the lesions disappear. The optimal duration of topical mechlorethamine therapy following clinical remission has not been fully established.

Mechlorethamine hydrochloride is applied topically to the skin as a gel containing 0.016% mechlorethamine. The commercially available mechlorethamine hydrochloride gel is for topical dermatologic use only.

Mechlorethamine also has been applied topically to the skin as a solution or ointment-based preparation compounded extemporaneously using mechlorethamine hydrochloride for injection. Solutions usually are prepared by dissolving 10 mg of mechlorethamine hydrochloride in 50-100 mL of water. Because of limited stability, solutions of the drug must be prepared immediately before use. Ointments containing mechlorethamine hydrochloride (typically in a concentration of 0.01 or 0.02% ) usually are prepared by dissolving the drug in dehydrated alcohol, filtering the solution to remove the insoluble sodium chloride that is present in the commercial preparation (although filtration may not be necessary), and mixing the drug-alcohol solution into petrolatum or another anhydrous ointment base (e.g., hydrophilic petrolatum). Clinicians should consult specialized references for detailed information on the preparation of topical mechlorethamine solutions and ointments.

Mechlorethamine should not be applied near or in the eyes, nose, or mouth. (See Mucosal or Eye Injury under Cautions: Warnings/Precautions.) Patients should be directed to wash their hands thoroughly with soap and water after handling or applying the drug.

Mechlorethamine gel must be stored in the freezer at -25 to -15degreesC prior to dispensing and in the original box in the refrigerator at 2-8degreesC after dispensing; any unused gel should be discarded 60 days after dispensing.

Mechlorethamine hydrochloride gel should be applied immediately (or within 30 minutes) after removal from the refrigerator; the gel should be returned to the refrigerator immediately after each use. The gel should be applied to completely dry skin at least 4 hours before or at least 30 minutes after showering or washing the affected areas. After application of the gel, the treated areas should be allowed to dry for 5-10 minutes before covering with clothing. Emollients (moisturizers) may be applied to the treated areas 2 hours before or 2 hours after application of the gel. Occlusive dressings should not be used on treated areas. Mechlorethamine gel is flammable; therefore, fire, flame, and smoking should be avoided until the gel has dried.

The manufacturer states that if a caregiver applies mechlorethamine hydrochloride gel to a patient, the caregiver must wear disposable nitrile gloves during application and must wash their hands thoroughly with soap and water after removing the gloves. In case of accidental skin exposure to mechlorethamine gel, a caregiver must immediately wash exposed areas thoroughly with soap and water for at least 15 minutes and remove contaminated clothing. If secondary exposure to the eyes, mouth, or nose occurs, the exposed area should be irrigated immediately for at least 15 minutes with copious amounts of water.

No dosing information is available for this tab.

Drug interaction studies with mechlorethamine hydrochloride gel have not been performed to date. The manufacturer states that systemic exposure has not been observed in patients receiving the drug topically and that systemic drug interactions are unlikely.

There are no contraindication interactions for this drug.

There are no severe interactions for this drug.

There are no moderate interactions for this drug.

Mechlorethamine gel is contraindicated in patients with known severe hypersensitivity to the drug.

• Lactation

• Basal cell carcinoma of skin
• Pregnancy
• Squamous cell carcinoma

There are no moderate contraindications for this drug.

Adverse effects reported in 5% or more of patients receiving mechlorethamine hydrochloride gel include dermatitis, pruritus, laboratory abnormalities (anemia, neutropenia, thrombocytopenia), bacterial skin infection, skin ulceration or blistering, and skin hyperpigmentation.

Less Frequent

• Anemia
• Neutropenic disorder
• Thrombocytopenic disorder

Rare or Very Rare

• Anaphylaxis

More Frequent

• Dermatitis due to topical drug
• Pruritus of skin

Less Frequent

• Actinic keratosis
• Acute abdominal pain
• Arthralgia
• Back pain
• Bacterial skin and skin structure infection
• Diarrhea
• Dizziness
• Headache disorder
• Lymphadenopathy
• Nausea
• Paresthesia
• Skin pigmentation enhancement
• Skin ulcer

Rare or Very Rare

• Basal cell carcinoma of skin
• Squamous cell carcinoma of skin

No enhanced messaging available.

Safety and efficacy of mechlorethamine gel in pediatric patients have not been established.

Category D. (See Users Guide and see Fetal/Neonatal Morbidity and Mortality under Cautions: Warnings/Precautions.)

It is not known whether mechlorethamine is distributed into human milk. Because of the potential for topical or systemic exposure to mechlorethamine through exposure to the mother's skin, a decision should be made whether to discontinue nursing or the drug, taking into account the importance of the drug to the woman.

Among patients receiving mechlorethamine gel in a clinical trial, a reduction of 50% or more in Composite Assessment of Index Lesion Severity (CAILS) score was reported in 44% of patients 65 years of age or older compared with 66% of younger patients. Adverse cutaneous reactions and adverse effects requiring drug discontinuance were reported in 70 and 38%, respectively, of patients 65 years of age or older receiving mechlorethamine gel compared with 58 and 14%, respectively, of younger patients receiving the gel.