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Valchlor Side Effects

Generic name: mechlorethamine topical

Medically reviewed by Last updated on Jul 6, 2022.

Note: This document contains side effect information about mechlorethamine topical. Some of the dosage forms listed on this page may not apply to the brand name Valchlor.

For the Consumer

Applies to mechlorethamine topical: topical application gel/jelly

Side effects requiring immediate medical attention

Along with its needed effects, mechlorethamine topical (the active ingredient contained in Valchlor) may cause some unwanted effects. Although not all of these side effects may occur, if they do occur they may need medical attention.

Check with your doctor immediately if any of the following side effects occur while taking mechlorethamine topical:

More common

  • Blistering, crusting, irritation, itching, or reddening of the skin
  • cracked, dry, scaly skin
  • pain, swelling, tenderness, or warmth on the skin

Side effects not requiring immediate medical attention

Some side effects of mechlorethamine topical may occur that usually do not need medical attention. These side effects may go away during treatment as your body adjusts to the medicine. Also, your health care professional may be able to tell you about ways to prevent or reduce some of these side effects.

Check with your health care professional if any of the following side effects continue or are bothersome or if you have any questions about them:

Less common

  • Darkening of the skin

For Healthcare Professionals

Applies to mechlorethamine topical: topical gel


Very common (10% or more): Dermatitis (56%), pruritus (20%), bacterial skin infection (11%)

Common (1% to 10%): Skin ulceration or blistering, skin hyperpigmentation[Ref]


Very common (10% or more): Reductions in hemoglobin, neutrophil count, or platelet count (13%)[Ref]


Common (1% to 10%): Nonmelanoma skin cancer[Ref]


Frequency not reported: Eye pain, burns, inflammation, photophobia, blurred vision, blindness, irreversible anterior eye injury[Ref]


The most common adverse reactions (5% or greater) are dermatitis, pruritus, bacterial skin infection, skin ulceration or blistering, and hyperpigmentation[Ref]

More about Valchlor (mechlorethamine topical)

Patient resources

Professional resources

Related treatment guides


1. "Product Information. Valchlor (mechlorethamine topical)." Ceptaris Therapeutics (2013):

Further information

Always consult your healthcare provider to ensure the information displayed on this page applies to your personal circumstances.

Some side effects may not be reported. You may report them to the FDA.