Skip to Content

Mustargen Side Effects

Generic Name: mechlorethamine

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

For the Consumer

Applies to mechlorethamine: intravenous powder for solution

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

Also, because of the way cancer medicines act on the body, there is a chance that they might cause other effects that may not occur until months or years after these medicines are used. These delayed effects may include certain types of cancer. Discuss these possible effects with your doctor.

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

Less common
  • Black, tarry stools
  • blood in urine or stools
  • cough or hoarseness
  • fever or chills
  • lower back or side pain
  • pain or redness at place of injection
  • painful or difficult urination
  • pinpoint red spots on skin
  • unusual bleeding or bruising
  • Shortness of breath, itching, or wheezing

Check with your doctor as soon as possible if any of the following side effects occur while taking mechlorethamine:

More common
  • Missing menstrual periods
  • painful rash
Less common
  • Dizziness
  • joint pain
  • loss of hearing
  • ringing in ears
  • swelling of feet or lower legs
  • Numbness, tingling, or burning of fingers, toes, or face
  • sores in mouth and on lips
  • yellow eyes or skin

Some side effects of mechlorethamine 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:

More common
  • Nausea and vomiting (usually lasts only 8 to 24 hours)
Less common
  • Confusion
  • diarrhea
  • drowsiness
  • headache
  • loss of appetite
  • metallic taste
  • weakness

This medicine may cause a temporary loss of hair in some people. After treatment with mechlorethamine has ended, normal hair growth should return.

After you stop using this medicine, it may still produce some side effects that need attention. During this period of time, check with your doctor immediately if you notice the following side effects:

  • Black, tarry stools
  • blood in urine or stools
  • cough or hoarseness
  • fever or chills
  • lower back or side pain
  • painful or difficult urination
  • pinpoint red spots on skin
  • unusual bleeding or bruising

For Healthcare Professionals

Applies to mechlorethamine: injectable powder for injection


The most commonly reported side effect was hematopoietic system depression.[Ref]


Rare (less than 0.1%): Hemolytic anemia
Frequency not reported: Lymphocytopenia, granulocytopenia, agranulocytosis, thrombocytopenia, pancytopenia, hyperheparenemia, hematopoietic system depression[Ref]


Frequency not reported: Hypersensitivity reactions, including anaphylaxis[Ref]


Frequency not reported: Nausea, vomiting, diarrhea, gum bleeding, gastrointestinal tract bleeding[Ref]


Frequency not reported: Alopecia, maculopapular skin eruption, erythema multiforme, petechiae, small subcutaneous hemorrhages[Ref]


Frequency not reported: Thrombosis, thrombophlebitis[Ref]


Frequency not reported: Vertigo, tinnitus, diminished hearing, chromosomal abnormalities, weakness, pain[Ref]


Frequency not reported: Jaundice[Ref]


Frequency not reported: Catamenia, oligomenorrhea, temporary or permanent amenorrhea, spermatogenesis, azoospermia, total germinal aplasia[Ref]


Frequency not reported: Herpes zoster[Ref]


Frequency not reported: Anorexia, hyperuricemia[Ref]


1. Cerner Multum, Inc. "UK Summary of Product Characteristics." O 0

2. "Product Information. Mustargen (mechlorethamine)." Merck & Co, Inc, West Point, PA.

Some side effects of Mustargen may not be reported. Always consult your doctor or healthcare specialist for medical advice. You may also report side effects to the FDA.

Disclaimer: Every effort has been made to ensure that the information provided is accurate, up-to-date and complete, but no guarantee is made to that effect. In addition, the drug information contained herein may be time sensitive and should not be utilized as a reference resource beyond the date hereof. This material does not endorse drugs, diagnose patients, or recommend therapy. This information is a reference resource designed as supplement to, and not a substitute for, the expertise, skill , knowledge, and judgement of healthcare practitioners in patient care. The absence of a warning for a given drug or combination thereof in no way should be construed to indicate safety, effectiveness, or appropriateness for any given patient. does not assume any responsibility for any aspect of healthcare administered with the aid of materials provided. The information contained herein is not intended to cover all possible uses, directions, precautions, warnings, drug interactions, allergic reactions, or adverse effects. If you have questions about the substances you are taking, check with your doctor, nurse, or pharmacist.