Chlormethine
Alkylating agents
Alkylating agentsHigh alert
An error with this medicine can cause serious harm: double checks and protocols are used.Pregnancy: avoid
Avoid in pregnancy. Chlormethine can harm the fetus; pregnancy and breastfeeding are avoided during treatment.
The first nitrogen mustard. Today mainly a skin gel for early mycosis fungoides; the old IV form was a strong vesicant.
Also called: mechlorethamine, nitrogen mustard, mustine
Quick facts
- Group
- Alkylating agents
- Target
- DNA (guanine N7), cross-linked by the mustard
- Used for
- Early-stage · Historically
- Key effects
- Gel · Gel · Injection
- Monitor
- Skin checks for new lesions · Injection
- ATC
- L01AA05
No doses: the clinician sets them by the current guideline.
Mechanism of action
Chlormethine is a bifunctional nitrogen mustard. In water it forms a reactive aziridinium ion that alkylates guanine bases; its two arms link DNA strands together. Cross-linked DNA cannot be copied or read, so dividing cells, and the malignant T cells in the skin when it is applied as a gel, stop growing and die.
- Forms a reactive aziridinium ion in water
- Alkylates guanine and cross-links the two DNA strands
- Cells cannot copy their DNA and die
Indications
- Early-stage (stage I) mycosis fungoides-type cutaneous T-cell lymphoma after previous skin-directed treatment (topical gel). Mycosis fungoides and Sézary syndrome (cutaneous T-cell lymphoma) →
- Historically, by injection, in Hodgkin lymphoma and other lymphomas and leukaemias; the injection is no longer marketed in the United States. Hodgkin lymphoma →
Adverse effects
Common
- Gel: skin redness, itching, blisters, ulcers and skin darkening
- Gel: allergic contact skin reactions
- Injection: nausea, vomiting, loss of appetite, tiredness
Contraindications
- Severe hypersensitivity to chlormethine
Key interactions
- Previous or planned radiotherapy or other chemotherapy
- Adds to marrow toxicity of the injectable form; reviewed before treatment.
What is monitored
- Skin checks for new lesions or growths during and after treatment
- Skin reactions in skin folds, face, genitals and anus
- Injection: blood counts and the infusion site
Administration and safety
- Gel: a thin layer on completely dry skin, then left to dry before clothes; no air- or water-tight dressings.
- Gel is flammable: no heat, flames or smoking until it has dried.
- Caregivers who apply it wear disposable nitrile gloves; accidental skin contact is washed at once with soap and water.
- Gel kept away from eyes, nose and mouth; if it gets in, the area is rinsed for a long time and emergency help is sought.
- Injectable form is a vesicant given only by trained staff into a running vein.
Pregnancy and breastfeeding
Avoid in pregnancy. Chlormethine can harm the fetus; pregnancy and breastfeeding are avoided during treatment.
Nursing care
- Teach how to apply the gel, wash hands afterwards and store it in the refrigerator.
- Teach to report blisters, ulcers or spreading redness, and any new skin growth.
- Check that caregivers wear nitrile gloves and know what to do after accidental contact.
- With the injection: watch the vein during infusion and stop at the first sign of leakage.
Pharmacokinetics
- Absorption
- Topical gel acts in the skin; the injectable form was given into a vein or into body cavities.
Test yourself
Think of the answer, then tap the question to see it.
Which reactive intermediate does chlormethine form in water?
An aziridinium ion, which alkylates guanine in DNA.
What is the main current use of chlormethine?
A topical gel for early mycosis fungoides-type cutaneous T-cell lymphoma.
Why must caregivers wear nitrile gloves when applying the gel?
Contact with the gel can cause skin reactions and raises the risk of skin cancer in anyone exposed.
Connections
← Back to the class: Alkylating agents
Educational content on how drugs work; not a prescribing guide and no substitute for a health professional's advice. No doses are given.
Sources: Mechlorethamine Topical: MedlinePlus Drug Information (MedlinePlus (U.S. National Library of Medicine), 2017); Mechlorethamine: MedlinePlus Drug Information (MedlinePlus (U.S. National Library of Medicine), 2024); Mechlorethamine Hydrochloride - NCI (National Cancer Institute, 2020); ATCDDD - ATC/DDD Index (WHO Collaborating Centre for Drug Statistics Methodology, 2026).
Spotted a mistake?We are always improving for the community. Tell us what is wrong and our team will review it.Report a mistake
Representative model, for educational purposes only.