Pemetrexed

Generic name: pemetrexed
Brand names: Alimta, Pemfexy
Dosage form: intravenous powder for injection (100 mg; 500 mg)
Drug class: Antimetabolites

Medically reviewed by A Ras MD.

What is Pemetrexed used for?

Pemetrexed is used to treat lung cancer. It is used to treat mesothelioma. Pemetrexed may be given to you for other reasons.

Description

Pemetrexed for injection, USP is a folate analog metabolic inhibitor. The drug substance, pemetrexed disodium (Amorphous), has the chemical name L-Glutamic acid, N-[4-[2-(2-amino-4,7-dihydro-4-oxo-1H-pyrrolo[2,3-d]pyrimidin-5-yl)ethyl]benzoyl]-, disodium salt. It is a white to cream color powder with a molecular formula C20H19N5Na2O6 and a molecular weight of 471.48. The pH of 1% solution is between 7.5 and 8.4. The structural formula is as follows:

Pemetrexed for injection, USP is supplied as a sterile lyophilized powder for intravenous infusion available in single-dose vials. The product is a white to either light-yellow or green-yellow lyophilized powder. Each 100 mg, 500 mg, or 1 g vial of pemetrexed for injection, USP contains pemetrexed disodium equivalent to 100 mg pemetrexed and 106 mg mannitol, 500 mg pemetrexed and 500 mg mannitol, or 1 g pemetrexed and 1 g mannitol, respectively. Hydrochloric acid and/or sodium hydroxide may have been added to adjust pH.

Mechanism of Action

Pemetrexed for injection, is a folate analog metabolic inhibitor that exerts its action by disrupts folate-dependent metabolic processes essential for cell replication. In vitro studies show that pemetrexed inhibits thymidylate synthase (TS), dihydrofolate reductase, and glycinamide ribonucleotide formyltransferase (GARFT), which are folate-dependent enzymes involved in the de novo biosynthesis of thymidine and purine nucleotides. Pemetrexed is taken into cells by membrane carriers such as the reduced folate carrier and membrane folate binding protein transport systems. Once in the cell, pemetrexed is converted to polyglutamate forms by the enzyme folylpolyglutamate synthetase. The polyglutamate forms are retained in cells and are inhibitors of TS and GARFT. Polyglutamation is a time- and concentration-dependent process that occurs in tumor cells and, is thought to occur to a lesser extent, in normal tissues. Polyglutamated metabolites are thought to have an increased intracellular half-life resulting in prolonged drug action in malignant cells.

Before taking pemetrexed, tell your doctor:

If you are allergic to pemetrexed; any part of this medicine; or any other drugs, foods, or substances. Tell your doctor about the allergy and what signs you had.
If you have any of these health problems: Bone marrow disease (like low white blood cell count, low platelet count, or anemia).
If you have kidney problems.
If you are breast-feeding. Do not breast-feed while you take pemetrexed and for 1 week after your last dose.

This is not a list of all drugs or health problems that interact with pemetrexed.

Tell your doctor and pharmacist about all of your drugs (prescription or OTC, natural products, vitamins) and health problems. You must check to make sure that it is safe for you to take pemetrexed with all of your drugs and health problems. Do not start, stop, or change the dose of any drug without checking with your doctor.

What are some things I need to know or do while I take pemetrexed?

Tell all of your health care providers that you take pemetrexed. This includes your doctors, nurses, pharmacists, and dentists.
You may have more of a chance of getting an infection. Wash hands often. Stay away from people with infections, colds, or flu. Some infections have been very bad and even deadly.
You may bleed more easily. Be careful and avoid injury. Use a soft toothbrush and an electric razor.
If diarrhea or throwing up happens, talk with the doctor. You will need to make sure to avoid dehydration and electrolyte problems.
Have blood work checked as you have been told by the doctor. Talk with the doctor.
If you have had or will be having radiation treatment, talk with your doctor. Worse side effects from radiation treatment have happened with pemetrexed.
This medicine is taken with other drugs. Be sure you know about the warnings, benefits, and risks of these other drugs. Talk with the doctor if you have questions or concerns about any of the drugs.
Very bad and sometimes deadly kidney problems have happened with pemetrexed. Call your doctor right away if you are unable to pass urine or if you have blood in the urine or a change in the amount of urine passed.
Some people have had lung problems with pemetrexed. Sometimes, this has been deadly. Call your doctor right away if you have signs of lung problems like shortness of breath or other trouble breathing, cough that is new or worse, or fever.
A very bad skin reaction (Stevens-Johnson syndrome/toxic epidermal necrolysis) may happen. It can cause very bad health problems that may not go away, and sometimes death. Get medical help right away if you have signs like red, swollen, blistered, or peeling skin (with or without fever); red or irritated eyes; or sores in your mouth, throat, nose, or eyes.
If you are 65 or older, use pemetrexed with care. You could have more side effects.
This medicine may affect being able to father a child. It is not known how long this effect lasts. Talk with the doctor.
This medicine may cause harm to the unborn baby if you take it while you are pregnant.
Women must use birth control while taking pemetrexed and for some time after the last dose. Ask your doctor how long to use birth control. If you get pregnant, call your doctor right away.
Men with a partner who may get pregnant must use birth control while taking pemetrexed and for some time after the last dose. Ask your doctor how long to use birth control. If your partner gets pregnant, call the doctor right away.

How is pemetrexed best taken?

Use pemetrexed as ordered by your doctor. Read all information given to you. Follow all instructions closely.

It is given as an infusion into a vein over a period of time.
Take folic acid 1 week before, during, and for 3 weeks after your last dose.
You will need to have vitamin B12 shots before your first dose and while you are using pemetrexed. Talk with your doctor.
Avoid taking ibuprofen for 2 days before, the day of, and 2 days after you use pemetrexed if you have kidney problems. Talk with the doctor.

What do I do if I miss a dose?

Call your doctor to find out what to do.

What are the side effects of pemetrexed that I need to call my doctor about immediately?

WARNING/CAUTION: Even though it may be rare, some people may have very bad and sometimes deadly side effects when taking a drug. Tell your doctor or get medical help right away if you have any of the following signs or symptoms that may be related to a very bad side effect:

Signs of an allergic reaction, like rash; hives; itching; red, swollen, blistered, or peeling skin with or without fever; wheezing; tightness in the chest or throat; trouble breathing, swallowing, or talking; unusual hoarseness; or swelling of the mouth, face, lips, tongue, or throat.
Signs of infection like fever, chills, very bad sore throat, ear or sinus pain, cough, more sputum or change in color of sputum, pain with passing urine, mouth sores, or wound that will not heal.
Signs of bleeding like throwing up or coughing up blood; vomit that looks like coffee grounds; blood in the urine; black, red, or tarry stools; bleeding from the gums; abnormal vaginal bleeding; bruises without a cause or that get bigger; or bleeding you cannot stop.
Signs of dehydration like dry skin, mouth, or eyes; thirst; fast heartbeat; dizziness; fast breathing; or confusion.
Signs of electrolyte problems like mood changes, confusion, muscle pain or weakness, a heartbeat that does not feel normal, seizures, not hungry, or very bad upset stomach or throwing up.
Signs of high blood sugar like confusion, feeling sleepy, more thirst, more hungry, passing urine more often, flushing, fast breathing, or breath that smells like fruit.
Feeling very tired or weak.
Very bad mouth pain or irritation.
A burning, numbness, or tingling feeling that is not normal.
Pale skin.
Swelling.

What are some other side effects of pemetrexed?

All drugs may cause side effects. However, many people have no side effects or only have minor side effects. Call your doctor or get medical help if any of these side effects or any other side effects bother you or do not go away:

Feeling tired or weak.
Constipation.
Mouth irritation or mouth sores.
Change in taste.
Hair loss.
Diarrhea, throwing up, upset stomach, and feeling less hungry are common with pemetrexed. If these happen, talk with your doctor about ways to lower these side effects. Call your doctor right away if any of these effects bother you, do not get better, or get very bad.

These are not all of the side effects that may occur. If you have questions about side effects, call your doctor. Call your doctor for medical advice about side effects.

You may report side effects to the FDA at 1-800-332-1088. You may also report side effects at https://www.fda.gov/medwatch.

If overdose is suspected:

If you think there has been an overdose, call your poison control center or get medical care right away. Be ready to tell or show what was taken, how much, and when it happened.