[Durgical](https://durgical.com/en/) › [DurgiPedia](https://durgical.com/en/durgipedia/) › [Pharmacology](https://durgical.com/en/pharmacology/) › [Alkylating agents](https://durgical.com/en/pharmacology/classes/alkylating-agents/) › Chlormethine # Chlormethine ## Alkylating agents? Alkylating agents ## High 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. Updated Nov 12, 2026 Also called: mechlorethamine, nitrogen mustard, mustine ## Quick facts **Group** [Alkylating agents](https://durgical.com/en/pharmacology/classes/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. On this page - The basics Mechanism of action - Indications - Adverse effects - Pharmacokinetics - Memory aid - Clinical What the labels mean - Safety Contraindications - Key interactions - What is monitored - Administration and safety - Pregnancy and breastfeeding - Nursing care - Study Test yourself - Connections Connections ## 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) →](https://durgical.com/en/conditions/mycosis-fungoides-and-sezary-syndrome/) - Historically, by injection, in Hodgkin lymphoma and other lymphomas and leukaemias; the injection is no longer marketed in the United States. [Hodgkin lymphoma →](https://durgical.com/en/conditions/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 ### Serious (rare, important) - Second skin cancers, also in treated and untreated areas and in people who touch the gel - Severe eye injury, even blindness, if the gel reaches the eyes - Injection: marrow suppression with infection or bleeding - Injection: severe tissue damage if it leaks out of the vein (vesicant) ## 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. ## Memory aid «Mustard first»: chlormethine was the first nitrogen mustard; the mustard arms grab guanine on both strands like a clamp. ## 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. [Add to my cards (3)](https://durgical.app/estudiar/?add=/en/pharmacology/chlormethine/) [More Pharmacology questions →](https://durgical.com/en/practice/?f=pharmacology) ## What the labels mean **High 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. ## Connections ## Related drugs 3 - [Cyclophosphamide](https://durgical.com/en/pharmacology/cyclophosphamide/) - [Melphalan](https://durgical.com/en/pharmacology/melphalan/) - [Bendamustine](https://durgical.com/en/pharmacology/bendamustine/) ## Related conditions 2 - [Mycosis fungoides and Sézary syndrome (cutaneous T-cell lymphoma)](https://durgical.com/en/conditions/mycosis-fungoides-and-sezary-syndrome/) - [Hodgkin lymphoma](https://durgical.com/en/conditions/hodgkin-lymphoma/) [← Back to the class: Alkylating agents](https://durgical.com/en/pharmacology/classes/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](https://medlineplus.gov/druginfo/meds/a614009.html) (MedlinePlus (U.S. National Library of Medicine), 2017); [Mechlorethamine: MedlinePlus Drug Information](https://medlineplus.gov/druginfo/meds/a682223.html) (MedlinePlus (U.S. National Library of Medicine), 2024); [Mechlorethamine Hydrochloride - NCI](https://www.cancer.gov/about-cancer/treatment/drugs/mechlorethaminehydrochloride) (National Cancer Institute, 2020); [ATCDDD - ATC/DDD Index](https://atcddd.fhi.no/atc_ddd_index/?code=L01AA05) (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. --- Source: https://durgical.com/en/pharmacology/chlormethine/ License: CC BY 4.0 (https://creativecommons.org/licenses/by/4.0/). Cite as: DurgiPedia (durgical.com), https://durgical.com/en/pharmacology/chlormethine/