Drug Formulary information is intended for use by healthcare professionals. It is not intended to be medical advice. Some of the information, including information about funding for cancer drugs, does not apply to all patients. Cancer treatment plans are unique to each patient. If you are a patient, please speak with your healthcare team to understand how this information applies to you.

drug-infosheet

mechlorethamine

Other Names
Mustargen®
Appearance
Clear, colorless solution
Medication Information Sheet
mechlorethamine (me-klor-ETH-a-meen)
This document provides general information about your medication. It does not replace the advice of your health care professional. Always discuss your therapy with your health care professional and refer to the package insert for more details.

Other Name: Mustargen®

Appearance:
Clear, colorless solution

What is this medication for?
  •  For treating Hodgkin's lymphoma or other types of cancer
What should I do before I have this medication?
  • Tell  your doctor if you have/had significant medical condition(s), especially if you have any allergies.
  • Mechlorethamine may harm the unborn baby.
  • Let your doctor know if you are breastfeeding, pregnant or plan to become pregnant.
  • People who have cancer or leukemia are at a higher risk of developing other cancers / leukemias or blood clots. Also, some cancer medications may increase this risk. You should discuss this with your doctor.
How will this medication affect sex, pregnancy and breastfeeding?
  • Do not use mechlorethamine if you are pregnant. If there is ANY chance that you or your partner may become pregnant, you and your partner together must:► Use 2 effective forms of birth control at the same time while taking this drug: Keep using birth control until 6 months after the last dose (general recommendation). Discuss with your healthcare team.
  • Tell your doctor right away if you or your partner becomes pregnant.
  • Do not breastfeed while on mechlorethamine treatment.
  • Effects on Fertility: Probable
  • Effects on Fertility: Probable
How is this medication given?
  • This drug is given by injection into a vein.

What else do I need to know while on this medication?
  • This medication can interact with other medications and can result in the treatment not working as well or cause severe side effects.

  • Make sure your health care team knows about all your medications (prescription, over-the-counter, herbals and supplements). Check with your health care team before starting or stopping any of them.

What are the side effects of this medication?
  • The following side effects are common or severe. You may not have all of the side effects. Other side effects may occur. If you have any unusual or bothersome symptoms, discuss with your doctor.

Side effects and what to do When to contact doctor?
More Common Side Effects

Diarrhea

  • May occur days to weeks after the drug is given / after treatment starts
  • Drink plenty of clear fluids. Limit hot, spicy, fried foods, foods/drinks with caffeine, orange or prune juice. 
  • Try a low-fiber BRAT diet (Bananas, white Rice, Apple sauce, Toast made with white bread).
  • Take anti-diarrhea drug(s) if given to you by your doctor.
  • Also see Diarrhea pamphlet.*
Contact your health care team if no improvement or if severe

Mouth sores, sores on lips (with high doses)

  • Maintain good mouth hygiene. Regular teethbrushing with a soft toothbrush or Toothette®, and  regular use of mouthwashes, especially after meals and at bedtime. Use alcohol-free mouthwashes.
  • Try rinsing mouth with a baking soda mouthwash: Half a teaspoon baking soda in a cup (250mL) of water
  • Avoid hot, spicy, acidic, hard or crunchy foods.
  • Check with your doctor or nurse as soon as you notice sores in mouth/lips or pain with swallowing. Your doctor may prescribe a prescription mouthwash to relieve mouth sores and prevent infection.
  • Also see Mouth Care pamphlet.*
Contact your health care team as soon as possible (office hours)

Unusual bleeding or bruising
(black stools, coughing up blood, purple or red dots on skin, bleeding that will not stop)

Fever, chills, infection
(low white blood cells)

  • May occur in days to weeks after the dose is given/ after starting treatment.
  • Phone your doctor right away or go to the nearest emergency department, if your oral temperature is over 38°C or 100.4°F (unless stated otherwise by your healthcare team). Tell the health care team that you are on chemotherapy.
  • Check your temperature, especially if you are feeling unwell with sweats, fever or chills. Take your temperature before using acetaminophen, since it may mask fever.
  • Use acetaminophen (Tylenol®) for fever, mild headache, aches or pains. Talk to your doctor before using ibuprofen (Advil®), naproxen (Aleve®) or aspirin, since these may increase bleeding risk. If taking aspirin regularly, talk to your doctor before you stop taking it.
  • Wash your hands often. Avoid sick people and crowds.
  • Use a soft toothbrush. Be careful not to cut or bruise yourself.
  • Check with your doctor before getting any vaccines, any surgeries or dental work.
  • Also see Low Platelets and Low White Blood Cells pamphlets.*
Get emergency medical help right away

Nausea and vomiting

  • May occur in hours to days after the dose is given/ after treatment starts.
  • Drink clear fluids and avoid large meals. Get fresh air and rest.
  • Limit spicy, fried foods or foods with a strong smell.
  • Take anti-nausea drug(s) exactly as directed by your doctor. It is easier to prevent nausea than to treat it.
  • Contact your doctor if nausea lasts more than 1 day or if any vomiting occurs.
  • Also see Nausea & Vomiting pamphlet.*
Contact your health care team if no improvement or if severe

Side effects and what to do When to contact doctor?
Less Common Side Effects, but may be Severe
Ringing in the ears, Hearing loss Contact your health care team as soon as possible (office hours)

Rapid killing of cancer cells when you start treatment may lead to build up of cell waste products

  • If mild, this may cause gout, with joint pains, but if severe, may cause fevers, kidney failure, confusion and be life-threatening.
  • You MUST take the preventive medicines given by your doctor AND
  • Drink plenty of fluids (6-8 glasses per day) and void (urinate) frequently.
Get emergency medical help right away

Liver problems
(yellow skin or eyes, dark urine)

Get emergency medical help right away

Pain, burning, redness, or swelling on skin where drug was injected

  • Let your healthcare team know right away when this happens, since this drug can harm or irritate tissue if it leaks from the vein during injection.
Get emergency medical help right away

Serious skin rash (may include blisters or skin peeling)

Contact your health care team if no improvement or if severe

Proteins in Urine; Kidney problems
(lower back pain, body swelling)

  • Also look for passing little or no urine, darkening or blood in urine, or recent unusual weight gain 
  • Your doctor may monitor for proteins in the urine regularly.
Get emergency medical help right away

Loss of consciousness, seizures

Get emergency medical help right away

For more links on how to manage your symptoms go to https://www.cancercareontario.ca/en/symptom-management.

The information set out in the medication information sheets, regimen information sheets, and symptom management information (for patients) contained in the Drug Formulary (the "Formulary") is intended to be used by health professionals and patients for informational purposes only. The information is not intended to cover all possible uses, directions, precautions, drug interactions or side effects of a certain drug, nor should it be used to indicate that use of a particular drug is safe, appropriate or effective for a given condition.

A patient should always consult a healthcare provider if he/she has any questions regarding the information set out in the Formulary. The information in the Formulary is not intended to act as or replace medical advice and should not be relied upon in any such regard. All uses of the Formulary are subject to clinical judgment and actual prescribing patterns may not follow the information provided in the Formulary.

Last Updated: July 21, 2026