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(pem uh treks ed)

Trade/other name(s): Alimta

Why would this drug be used?

Pemetrexed is used to treat certain types of lung cancer. It is also used for treating malignant pleural mesothelioma, which is a cancer in the lining of the chest cavity around the lungs. This type of cancer is usually linked to asbestos exposure.

How does this drug work?

Pemetrexed is a part of a general group of chemotherapy drugs called anti-metabolites. It prevents cells from using folate to make DNA and RNA. Because cancer cells need these substances to make new cells, pemetrexed helps to stop the growth of cancer cells.

Before taking this medicine

Tell your doctor…

  • If you are allergic to anything, including medicines, dyes, additives, or foods.
  • If you have any medical conditions such as kidney disease, liver disease (including hepatitis), heart disease, congestive heart failure, diabetes, gout, or infections. These conditions may require that your medicine dose, regimen, or timing be changed.
  • If you are pregnant, trying to get pregnant, or if there is any chance of pregnancy. This drug may cause birth defects if it is taken at the time of conception or during pregnancy. Check with your doctor about what kinds of birth control can be used with this medicine.
  • If you are breast-feeding. It is not known whether this drug passes into breast milk. If it does, it could harm the baby.
  • If you think you might want to have children in the future. Some drugs can cause sterility. Talk with your doctor about the possible risk with this drug and the options that may preserve your ability to have children.
  • About any other prescription or over-the-counter medicines you are taking, including vitamins and herbs. In fact, keeping a written list of each of these medicines (including the doses of each and when you take them) with you in case of emergency may help prevent complications if you get sick.

Interactions with other drugs

Probenecid, a drug used to treat gout, can cause pemetrexed to stay in your system longer. This may worsen its side effects.

If taken with other medicines that can harm the kidneys, like aminoglycosides (a type of antibiotic that is usually given in the vein, such as gentamicin, tobramycin, amikacin, streptomycin, and others), or non-steroidal anti-inflammatory drugs (see below) there is a higher risk of harmful side effects.

Medicines such as aspirin and other non-steroid drugs for pain, fever, or inflammation, like ibuprofen (Advil, Motrin), naproxen (Aleve, Naprosyn), fenoprofen, diclofenac, fenaprofen, indomethacin, suprofen, tolmetin, meclofenamate, and others can cause pemetrexed to stay in your system longer. This can seriously worsen its side effects. Check with your doctor, nurse, or pharmacist to find out if any of the medicines you are taking are NSAIDs. Most of these medicines must be stopped a few days before you get pemetrexed, and cannot be resumed until the third day after the dose is given.

Any drugs or supplements that interfere with blood clotting can raise the risk of bleeding during treatment with pemetrexed. These include:

  • Vitamin E
  • Non-steroid anti-inflammatory drugs (see examples above)
  • Warfarin (Coumadin)
  • Dabigatran (Pradaxa)
  • Heparin injections of any type
  • Ticlopidine (Ticlid)
  • Clopidogrel (Plavix)

Note that many cold, flu, fever, and headache remedies contain aspirin or ibuprofen. Ask your pharmacist if you aren't sure what's in the medicines you take.

Check with your doctor, nurse, or pharmacist about other medicines, vitamins, herbs, and supplements, and whether alcohol can cause problems with this medicine.

Interactions with foods

No serious interactions with food are known at this time. Check with your doctor, nurse, or pharmacist about whether foods may be a problem.

Tell all the doctors, dentists, nurses, and pharmacists you visit that you are taking this drug.

How is this drug taken or given?

Pemetrexed is given as an injection in the vein (intravenously, I.V.) over 10 minutes, once every 3 weeks. The dose depends on your body size. The dose may be adjusted or delayed depending upon your blood counts, kidney function, and general condition.

Your doctor will give you a prescription for a steroid medicine (like dexamethasone) to take twice a day for 3 days starting the day before treatment. This lowers the chance that you will get skin reactions.

You will need to take folic acid (a vitamin) and vitamin B12 starting the week before your treatment with pemetrexed. You must take 350 to 1000 micrograms of folic acid every day for at least 5 days out of the 7 days before you start your first treatment with pemetrexed. Then, once you start treatment, you need to take folic acid every day. You will need to keep taking it for 21 days after you get your final treatment. This helps protect your body's normal cells from the effects of the chemotherapy. You can buy folic acid over the counter (without a prescription). If you have any questions, or need help in deciding which folic acid product to use, ask your nurse, pharmacist, or doctor. Your doctor and nurse will give you your first vitamin B12 shot the week before your first pemetrexed treatment, and then about every 9 weeks during treatment.

When treating mesothelioma, pemetrexed is given along with cisplatin, another chemotherapy drug. Cisplatin is given over 2 hours starting about 30 minutes after the pemetrexed injection ends. You will need to drink as much fluid as you can before and after the cisplatin to keep your kidneys working well, and will probably get extra fluid by vein during the treatment (see also Cisplatin).


Your doctor will likely test your blood throughout your treatment, looking for possible effects of the drug on blood counts (described below) or on other body organs. Based on the test results, you may be given medicines to help treat any effects. Your doctor may also need to reduce or delay your next dose of this drug, or even stop it altogether. Be sure to keep all your appointments for lab tests and doctor visits.

This drug can lower your white blood cell count, especially in the weeks after the drug is given. This can increase your chance of getting an infection. Be sure to let your doctor or nurse know right away if you have any signs of infection, such as fever (100.5° F or higher), chills, diarrhea, mouth sores, pain when passing urine, a new cough, or bringing up sputum.

This drug may lower your platelet count in the weeks after it is given, which can increase your risk of bleeding. Speak with your doctor before taking any drugs or supplements that might affect your body's ability to stop bleeding, such as aspirin or aspirin-containing medicines, warfarin (Coumadin), or vitamin E. Tell your doctor right away if you have unusual bruising, or bleeding such as nosebleeds, bleeding gums when you brush your teeth, or black, tarry stools.

This drug may lower your red blood cell count. If this occurs, it is usually a few weeks after starting treatment. A low red blood cell count (known as anemia) can cause shortness of breath, or make you to feel weak or tired all the time. Your doctor may give you medicines to help prevent or treat this condition, or you may need to get blood transfusions.

Do not get any immunizations (vaccines), either during or after treatment with this drug, without your doctor's OK. Pemetrexed may affect your immune system. This could make vaccinations ineffective, or even lead to serious infections if you get a live virus vaccine during or soon after treatment. Try to avoid contact with people who have recently received a live virus vaccine, such as the oral polio vaccine or smallpox vaccine. Check with your doctor about this.

Pemetrexed can cause you to feel tired. You may feel tired and weak for a few days after your treatment. Tell your doctor or nurse if you have severe weakness or tiredness.

This drug may cause sores in the mouth or on the lips, which often occur within the first few weeks after starting treatment. This can cause mouth pain, bleeding, or even trouble eating. Your doctor or nurse can suggest ways to reduce this, such as changing the way you eat or how you brush your teeth. If needed, your doctor can prescribe medicine to help with the pain.

You may have nausea and vomiting on the day you receive this drug or in the first few days afterward. Your doctor may give you medicine before your treatment to help prevent nausea and vomiting. You will likely also get a prescription for an anti-nausea medicine that you can take at home. It is important to have these medicines on hand and to take them as prescribed by your doctor.

Call your doctor if you can't hold down liquids for more than a day, if you have severe diarrhea, or if you suspect that you are getting dehydrated.

Pemetrexed can cause a rash or itching, which usually starts after a treatment and goes away before the next treatment. Tell your nurse or doctor right away if you notice fever or skin blistering, or if you have severe rash or itching. Blisters over a large part of the body can become life-threatening.

Avoid pregnancy during and for at least a few months after treatment, since exposure to the drug can harm the fetus. Talk with your doctor about this.

Possible side effects

You will probably not have most of the following side effects, but if you have any talk to your doctor or nurse. They can help you understand the side effects and cope with them.


  • Low white blood cell count with increased risk of infection*
  • Low platelet count with increased risk of bleeding*
  • Low red blood cell count with increased risk of fatigue and shortness of breath*
  • Nausea*
  • Vomiting*
  • Constipation
  • Sores in the mouth or on the lips, or in your esophagus (swallowing tube)*
  • Loss of appetite
  • Fatigue (tiredness)
  • Rash, skin peeling, or itching*
  • Trouble breathing

Less common

  • Diarrhea
  • Hair loss or thinning (can include facial and body hair as well as scalp hair)
  • Numbness, tingling, pain, or weakness in hands or feet
  • Changes in taste
  • Abnormal blood tests which suggest that the drug is affecting the liver or kidneys (Your doctor will discuss the importance of this finding, if any.)


  • Blood clots
  • Severe allergic reaction, with rash, skin welts, trouble breathing, tightness in the throat, swelling of the mouth, tongue, or eyes
  • Serious skin rashes with blisters and peeling*
  • Death due to infection, bleeding, allergic reaction, skin rash, or other causes

*See the "Precautions" section for more detailed information.

There are other side effects not listed above that can also occur in some patients. Tell your doctor or nurse if you develop these or any other problems.

FDA approval

Yes – first approved in 2004.

Disclaimer: This information does not cover all possible uses, actions, precautions, side effects, or interactions. It is not intended as medical advice, and should not be relied upon as a substitute for talking with your doctor, who is familiar with your medical needs.

Last Medical Review: 07/16/2012
Last Revised: 07/16/2012