Trimetrexate is used in the treatment of moderate to severe cases of pneumocystis carinii pneumonia (PCP) in patients
wih AIDS. PCP is a type of pneumonia caused by the microorganism Pneumocystis carinii. Other less common uses
for this drug include the treatment of a number of different forms of cancer (colorectal, head, neck and lung).
Trimetrexate is usually used if a patient has experienced toxic side effects or does not respond to more traditional
therapy such as trimethoprim-sulfamethoxazole (TMP-SMX, Septra, Bactrim), dapsone/trimethoprim or pentamidine.
HOW should this drug be taken ?
For the treatment of PCP in patients who are immunocompromised (eg. AIDS patients), trimetrexate is given
intravenously (I.V.) over 60 to 90 minutes once daily for a total period of 21 days. The actual dose is determined by your weight.
Another agent called leucovorin (folinic acid) is given every 6 hours along with trimetrexate and must be continued for 72
hours following the last dose of trimetrexate. Leucovorin may be given intravenously or taken orally (tablet). It is very
important that leucovorin is taken at the recommended dose and duration since it prevents/minimizes the risk of potentially serious and life threatening toxicity.
What should you do if you FORGET a dose?
Your dose of trimetrexate will be given to you by your nurse or physician. It is important that you keep your doctor and
laboratory appointments, so that you receive your medication. Keeping your appointments will also ensure that your progress can be assessed regularly.
What ADVERSE EFFECTS can this drug cause ? What should you do about them?
Trimetrexate can several potentially serious side-effects, which are usually preventable. Many of these affect the blood.
Myelosuppression is the inhibition of bone marrow activity which results in decreased production of white blood cells and
platelets. The risk of experiencing such effects may be increased if you are on other medications with similar side
effects. Trimetrexate may also cause some reversible toxicities to your kidneys and liver. You may experience nausea,
vomiting, rash and develop stomatitis (inflammation and sores in the mouth). Taking leucovorin with your trimetrexate
may help reduce/eliminate the risk of experiencing many of these effects. Blood tests and other lab tests will be done regularly to monitor your progress and to watch for these side effects.
What other PRECAUTIONS should you follow while using this drug ?
Trimetrexate may interact with other drugs. These interactions may lead to increased drug toxicity or a decreased
benefit of the drug. It is important to let your doctor or pharmacist know about other drugs you are taking. This includes
immunizations, vaccines and even medications which you can buy without a prescription. Also, do not start taking other
medications during your trimetrexate therapy without first discussing with one of the above health care professionals.
Medications to avoid if possible while you are taking trimetrexate include AZT (zidovudine, Retrovir). Medications to use
cautiously while you are taking trimetrexate include erythromycin, rifampin, rifabutin, ketoconazole, fluconazole, and cimetidine.
Since the liver and kidney are important in helping to break down and eventually eliminate trimetrexate from the body, it
is important to let your physician know if you have a history of liver or kidney disease.
Since trimetrexate can lower the white blood cells and platelets, dental work should be performed prior to starting
trimetrexate or delayed until blood cell counts after therapy return to normal. By doing so, the risk of getting an infection is minimized.
Since trimetrexate can be harmful to the fetus and women of child-bearing age, it is important to avoid the use of
trimetrexate in pregnancy. Due to the potentially serious side effects, breast-feeding is not recommended during trimetrexate therapy.
IF YOU HAVE ANY QUESTIONS OR CONCERNS ABOUT THIS MEDICATION, PLEASE DISCUSS THEM WITH YOUR NURSE, PHARMACIST, OR PHYSICIAN.
PLEASE WRITE DOWN YOUR QUESTIONS OR CONCERNS TO ENSURE THEY ARE ADDRESSED
