Trimetrexate (Injection)

Trimetrexate (Injection)

Trimetrexate (tri-me-TREX-ate)

Treats an infection called Pneumocystis carinii pneumonia (also called PCP).

Brand Name(s):
There may be other brand names for this medicine.

When This Medicine Should Not Be Used:

You should not receive this medicine if you have had an allergic reaction to trimetrexate, leucovorin, or methotrexate (Rheumatrexreg;), or if you are pregnant.

How to Use This Medicine:


  • This medicine is very strong and can have many side effects. Before receiving this medicine, make sure you understand all the risks and benefits. It is important for you to work closely with your doctor during your treatment.  
  • You will receive this medicine while you are in a hospital or cancer treatment center. A nurse or other trained health professional will give you this medicine. It may also be given by a home health caregiver.  
  • Your doctor will prescribe your exact dose and tell you how often it should be given. This medicine is given through a needle placed in one of your veins.  
  • You will be given a second drug called leucovorin (Wellcovorinreg;) on the same days that you receive trimetrexate. You also need to be given leucovorin for 3 days after your last dose of trimetrexate. Leucovorin helps prevent some very serious side effects of trimetrexate, including possible death. Follow all of your doctor’s instructions about both medicines.

If a dose is missed:

  • This medicine needs to be given on a fixed schedule. If you miss a dose or forget to use your medicine, call your doctor or pharmacist for instructions.

How to Store and Dispose of This Medicine:

  • If you store this medicine at home, keep it at room temperature, away from heat, moisture, and direct light. After the powder medicine has been mixed with the liquid, you should use it right away. If you must store the mixture in the refrigerator, store it only up to 24 hours. Do not freeze.  
  • Ask your pharmacist, doctor, or health caregiver about the best way to dispose of any leftover or outdated medicine and used IV bags, vials, or tubing.  
  • Keep all medicine away from children and never share your medicine with anyone.

Drugs and Foods to Avoid:

Ask your doctor or pharmacist before using any other medicine, including over-the-counter medicines, vitamins, and herbal products.

  • Make sure your doctor knows if you are also using zidovudine (AZT, Retrovirreg;), erythromycin (Erythro-Tabreg;), rifampin (Rifadinreg;, Rifamatereg;, Rifaterreg;), rifabutin (Mycobutinreg;), cimetidine (Tagametreg;), acetaminophen, (Tylenolreg;), or medicine to treat fungal infections (such as clotrimazole, fluconazole, itraconazole, ketoconazole, Diflucanreg;, Nizoralreg;, Sporanoxreg;).

Warnings While Using This Medicine:

  • Using this medicine while you are pregnant can harm your unborn baby. Use an effective form of birth control to keep from getting pregnant. If you think you have become pregnant while using the medicine, tell your doctor right away.  
  • Make sure your doctor knows if you are breastfeeding, or if you have kidney disease, liver disease, or blood problems.  
  • Your doctor will need to check your blood at regular visits while you are using this medicine. Be sure to keep all appointments.

Possible Side Effects While Using This Medicine:

Call your doctor right away if you notice any of these side effects:

  • Allergic reaction: Itching or hives, swelling in your face or hands, swelling or tingling in your mouth or throat, chest tightness, trouble breathing  
  • Dark-colored urine or pale stools  
  • Decrease in how much or how often you urinate  
  • High fever (over 105 degrees)  
  • Lightheadedness or fainting  
  • Nausea, vomiting, loss of appetite, pain in your upper stomach  
  • Sores or white patches on your lips, mouth, or throat  
  • Unusual bleeding, bruising, or weakness  
  • Yellow skin or eyes

If you notice these less serious side effects, talk with your doctor:

  • Mild nausea, vomiting

Johns Hopkins patient information

Copyright 1996-2014 Cerner Multum, Inc. Version: 16.02.
Revision date: July 6, 2011
Last revised: by Dave R. Roger, M.D.

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CONDITIONS OF USE: The information in this database is intended to supplement, not substitute for, the expertise and judgment of healthcare professionals. The information is not intended to cover all possible uses, directions, precautions, drug interactions or adverse effects, nor should it be construed to indicate that use of a particular drug is safe, appropriate or effective for you or anyone else. A healthcare professional should be consulted before taking any drug, changing any diet or commencing or discontinuing any course of treatment.

The drug reference included in this section is provided by Cerner Multum, Inc., of Denver, Colorado. Armenian Medical Network receives monthly updates from Multum.