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Brand names: Valchlor

What is mechlorethamine used for?

  • Mechlorethamine is used to treat a type of lymphoma that affects the skin.

Before taking mechlorethamine, tell your doctor:

  • If you are allergic to mechlorethamine; any part of this medicine; or any other drugs, foods, or substances. Tell your doctor about the allergy and what signs you had.
  • If you are breast-feeding. Do not breast-feed while you take mechlorethamine.

This medicine may interact with other drugs or health problems.

Tell your doctor and pharmacist about all of your drugs (prescription or OTC, natural products, vitamins) and health problems. You must check to make sure that it is safe for you to take mechlorethamine with all of your drugs and health problems. Do not start, stop, or change the dose of any drug without checking with your doctor.

What are some things I need to know or do while I take mechlorethamine?

  • Tell all of your health care providers that you take mechlorethamine. This includes your doctors, nurses, pharmacists, and dentists.
  • If you get mechlorethamine in your eyes, it may cause eye problems like eye pain, burns, swelling, or blurred eyesight. Sometimes, blindness and long-lasting eye injury may happen. Do not touch your eyes while using mechlorethamine. If you get mechlorethamine in your eyes, flush with water for at least 15 minutes and call your doctor.
  • Talk with your doctor before you use other drugs or products on your skin.
  • Do not let your skin where the gel was used touch anyone else's skin while wearing the gel. Cover the treated skin with clothes.
  • If anyone else touches the gel, wash the skin with soap and water for at least 15 minutes and take off any clothing that gets gel on it.
  • This medicine may add to the chance of getting other skin cancers. Talk with the doctor.
  • This medicine may catch on fire. Do not use near an open flame or while smoking.
  • Avoid fire, flames, or smoking until the gel has dried.
  • If you are 65 or older, use mechlorethamine with care. You could have more side effects.
  • This medicine may cause harm to the unborn baby if you take it while you are pregnant.
  • Use birth control that you can trust to prevent pregnancy while taking mechlorethamine.
  • If you are pregnant or you get pregnant while taking mechlorethamine, call your doctor right away.

How is mechlorethamine best taken?

Use mechlorethamine as ordered by your doctor. Read all information given to you. Follow all instructions closely.

  • Do not take mechlorethamine by mouth. Use on your skin only. Keep out of your mouth, nose, and eyes (may burn).
  • You will need to take special care when handling mechlorethamine. Check with the doctor or pharmacist to see how to handle mechlorethamine.
  • Wash your hands before and after use. Do not wash your hands after use if putting this on your hand.
  • Caregivers need to wear special gloves when putting on mechlorethamine and wash hands after use.
  • Put on right away or within 30 minutes after taking mechlorethamine out of the refrigerator.
  • Put back in the refrigerator right after each use.
  • Put on clean, dry skin.
  • Put a thin layer on the affected skin.
  • Avoid putting on healthy skin.
  • Let gel dry before covering with clothing.
  • Wait at least 30 minutes after you bathe or shower before putting on mechlorethamine.
  • Do not bathe, shower, or swim for 4 hours after putting on.
  • Do not use coverings (bandages, dressings, make-up) unless told to do so by the doctor.
  • Use as you have been told, even if your signs get better.

What do I do if I miss a dose?

  • Put on a missed dose as soon as you think about it.
  • If it is close to the time for your next dose, skip the missed dose and go back to your normal time.
  • Do not put on 2 doses at the same time or extra doses.

What are the side effects of mechlorethamine that I need to call my doctor about immediately?

WARNING/CAUTION: Even though it may be rare, some people may have very bad and sometimes deadly side effects when taking a drug. Tell your doctor or get medical help right away if you have any of the following signs or symptoms that may be related to a very bad side effect:

  • Signs of an allergic reaction, like rash; hives; itching; red, swollen, blistered, or peeling skin with or without fever; wheezing; tightness in the chest or throat; trouble breathing, swallowing, or talking; unusual hoarseness; or swelling of the mouth, face, lips, tongue, or throat.
  • Blisters or sores.
  • Redness.
  • Swelling.
  • Signs of skin infection like oozing, heat, swelling, redness, or pain.
  • Skin ulcers.
  • A skin lump or growth.
  • Change in color or size of a mole.

What are some other side effects of mechlorethamine?

All drugs may cause side effects. However, many people have no side effects or only have minor side effects. Call your doctor or get medical help if any of these side effects or any other side effects bother you or do not go away:

  • Itching.
  • Change in color of skin.

These are not all of the side effects that may occur. If you have questions about side effects, call your doctor. Call your doctor for medical advice about side effects.

You may report side effects to the FDA at 1-800-332-1088. You may also report side effects at

If overdose is suspected:

If you think there has been an overdose, call your poison control center or get medical care right away. Be ready to tell or show what was taken, how much, and when it happened.

How do I store and/or throw out mechlorethamine?

  • Store in a refrigerator.
  • Store in original container.
  • Protect from heat or open flame.
  • Check with your pharmacist if drug is left at room temperature for more than 1 hour a day.
  • Throw away any part not used after 3 months.
  • Keep all drugs in a safe place. Keep all drugs out of the reach of children and pets.
  • Throw away unused or expired drugs. Do not flush down a toilet or pour down a drain unless you are told to do so. Check with your pharmacist if you have questions about the best way to throw out drugs. There may be drug take-back programs in your area.

Consumer information use and disclaimer

  • If your symptoms or health problems do not get better or if they become worse, call your doctor.
  • Do not share your drugs with others and do not take anyone else's drugs.
  • This medicine comes with an extra patient fact sheet called a Medication Guide. Read it with care. Read it again each time mechlorethamine is refilled. If you have any questions about mechlorethamine, please talk with the doctor, pharmacist, or other health care provider.
  • If you think there has been an overdose, call your poison control center or get medical care right away. Be ready to tell or show what was taken, how much, and when it happened.

This information should not be used to decide whether or not to take mechlorethamine or any other medicine. Only the healthcare provider has the knowledge and training to decide which medicines are right for a specific patient. This information does not endorse any medicine as safe, effective, or approved for treating any patient or health condition. This is only a brief summary of general information about this medicine. It does NOT include all information about the possible uses, directions, warnings, precautions, interactions, adverse effects, or risks that may apply to mechlorethamine. This information is not specific medical advice and does not replace information you receive from the healthcare provider. You must talk with the healthcare provider for complete information about the risks and benefits of using this medicine.

Source: Wolters Kluwer Health. Last updated April 5, 2023.