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Generic name: pemetrexed [ pem-e-TREX-ed ]
Brand names: Alimta, Pemfexy, Pemrydi RTU
Dosage forms: intravenous powder for injection (1 g; 100 mg; 500 mg; 750 mg), intravenous solution (10 mg/mL; 25 mg/mL)
Drug class: Antimetabolites

Medically reviewed by on Aug 31, 2023. Written by Cerner Multum.

What is pemetrexed?

Pemetrexed is used in adults to treat a certain type of lung cancer that has returned or has spread to other parts of the body (metastatic).

Pemetrexed is also used to treat a type of cancer that affects the lining of the lungs in adults who cannot have surgery.

Pemetrexed may be used in combination with other cancer medicines.

Pemetrexed may also be used for purposes not listed in this medication guide.

Pemetrexed side effects

Get emergency medical help if you have signs of an allergic reaction (hives, difficult breathing, swelling in your face or throat) or a severe skin reaction (fever, sore throat, burning eyes, skin pain, red or purple skin rash with blistering and peeling).

Pemetrexed may cause serious side effects. Call your doctor at once if you have:

Your cancer treatments may be delayed or permanently discontinued if you have certain side effects.

Common side effects of pemetrexed may include:

This is not a complete list of side effects and others may occur. Call your doctor for medical advice about side effects. You may report side effects to FDA at 1-800-FDA-1088.


Use only as directed. Tell your doctor if you use other medicines or have other medical conditions or allergies.

Before taking this medicine

You should not be treated with pemetrexed if you are allergic to it.

Tell your doctor if you have ever had:

Pemetrexed can harm an unborn baby if the mother or the father is using pemetrexed.

It may be harder for you to get a woman pregnant while you are using this medicine. You should still use birth control to prevent pregnancy because the medicine can harm an unborn baby.

Do not breastfeed while using this medicine, and for at least 1 week after your last dose.

How is pemetrexed given?

Pemetrexed is given as an infusion into a vein for 10 minutes. A healthcare provider will give you this injection.

Pemetrexed is usually given once every 3 weeks. Your doctor will determine how long you should use pemetrexed.

You will be given other medications such as folic acid, vitamin B12, and a steroid to help prevent serious side effects. Keep taking these medicines for as long as your doctor has prescribed.

You may need frequent medical tests and your cancer treatments may be delayed based on the results.

Your blood pressure may get too low or you may get dehydrated during prolonged illness. Call your doctor if you are sick with vomiting or diarrhea.

What happens if I miss a dose?

Call your doctor for instructions if you miss an appointment for your pemetrexed injection.

What happens if I overdose?

In a medical setting an overdose would be treated quickly.

What should I avoid while receiving pemetrexed?

If you have kidney problems, avoid taking ibuprofen (Advil, Motrin) 2 days before, during, and 2 days after you are treated with pemetrexed.

What other drugs will affect pemetrexed?

Pemetrexed can harm your kidneys, especially if you also use certain medicines for pain or arthritis (including ibuprofen, Advil, Motrin, and Aleve).

Other drugs may affect pemetrexed, including prescription and over-the-counter medicines, vitamins, and herbal products. Tell your doctor about all other medicines you use.

Popular FAQ

Pemetrexed works in cancer by blocking certain enzymes involved in folate metabolism and DNA synthesis, which interferes with the process needed for a cell to divide and replicate. Continue reading

Further information

Remember, keep this and all other medicines out of the reach of children, never share your medicines with others, and use this medication only for the indication prescribed.

Always consult your healthcare provider to ensure the information displayed on this page applies to your personal circumstances.