Pemetrexed is a chemotherapy drug usually given to treat non-small cell lung cancer (NSCLC) and pleural mesothelioma; a type of cancer that affects the lining of the lung.
This information should ideally be read with our general information about chemotherapy and your type of cancer.
You'll see your hospital doctor regularly while you have this treatment so they can monitor the effects of the chemotherapy.
What pemetrexed looks like
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Pemetrexed is a colourless fluid.
Pemetrexed is given in one of the following ways:
as a drip (infusion) through a fine tube inserted into a vein, usually in the back of your hand (cannula)
through a fine, plastic tube inserted under the skin and into a vein near your collarbone (central line)
through a fine tube inserted into a vein in the crook of your arm (PICC line).
The infusion takes about 10 minutes.
You'll be given folic acid and vitamin B12 before your treatment with pemetrexed begins and throughout your chemotherapy. It's very important to take folic acid and B12, as they reduce the side effects of pemetrexed without reducing its effectiveness.
Folic acid can be taken as a tablet. It's usually taken a few days before the first treatment and then every day until three weeks after treatment with pemetrexed is completed.
Vitamin B12 is injected into a muscle one week before the first treatment, and again with every third treatment with pemetrexed (roughly every nine weeks).
Chemotherapy is usually given as a course of several sessions (cycles) of treatment over a few months. The length of your treatment and the number of cycles you have will depend on the type of cancer you're being treated for.
Pemetrexed is sometimes given alongside other chemotherapy drugs as part of a combination treatment (regimen). Your nurse or doctor will discuss your treatment plan with you.
Before you begin your treatment your doctor will arrange for you to have blood tests. You'll usually be given anti-sickness drugs before and/or during your treatment.
Each person’s reaction to chemotherapy is different. Some people have very few side effects while others may experience more. The side effects described here won't affect everyone who has pemetrexed and may be different if you're having more than one type of chemotherapy drug.
We have outlined the most common side effects but haven't included those that are rare and unlikely to affect you. If you notice any effects that aren't listed here, discuss them with your doctor, chemotherapy nurse or pharmacist.
Risk of infection
Pemetrexed can reduce the number of white blood cells, which help fight infection. White blood cells are produced by the bone marrow. If the number of your white blood cells is low you'll be more prone to infections. A low white blood cell count is called neutropenia.
Neutropenia begins seven days after treatment, and your resistance to infection is usually at its lowest 10-14 days after chemotherapy. The number of your white blood cells will then increase steadily and usually return to normal before your next cycle of chemotherapy is due.
Contact your doctor or the hospital straight away if:
your temperature goes above 38°C (100.4°F)
you suddenly feel unwell even with a normal temperature.
You'll have a blood test before having more chemotherapy to check the number of white blood cells. Occasionally, your treatment may need to be delayed if the number of your blood cells (blood count) is still low.
Bruising and bleeding
Pemetrexed can reduce the production of platelets, which help the blood to clot. Tell your doctor if you have any unexplained bruising or bleeding, such as nosebleeds, bleeding gums, blood spots or rashes on the skin. You may need to have a platelet transfusion if your platelet count is low.
Pemetrexed can reduce the number of red blood cells, which carry oxygen around the body. A low red blood cell count is called anaemia. This may make you feel tired and breathless. Tell your doctor or nurse if you have these symptoms. You may need to have a blood transfusion if the number of red blood cells becomes too low.
Feeling tired is a common side effect of chemotherapy, especially towards the end of treatment and for some weeks after it’s over. It’s important to try to pace yourself and get as much rest as you need. Try to balance this with some gentle exercise, such as short walks, which will help. If tiredness is making you feel sleepy, don’t drive or operate machinery.
Your mouth may become sore or dry, or you may notice small ulcers during this treatment. Drinking plenty of fluids, and cleaning your teeth regularly and gently with a soft toothbrush, can help reduce the risk of this happening.
Some people may find sucking on ice soothing. Tell your nurse or doctor if you have any of these problems as they can prescribe mouthwashes and medicine to prevent or clear mouth infections. You may find our section on mouth care during chemotherapy helpful
Feeling sick (nausea) and being sick (vomiting)
This may begin soon after the treatment is given and can last for a few days. Your doctor can prescribe very effective anti-sickness (anti-emetic) drugs to prevent or greatly reduce nausea and vomiting. If the sickness isn't controlled, or if it continues, tell your doctor; they can prescribe other anti-sickness drugs that may be more effective.
Some anti-sickness drugs can cause constipation. Let your doctor or nurse know if this is a problem.
Loss of appetite
Some people lose their appetite while they’re having chemotherapy. This can be mild and may only last a few days. If it doesn’t improve you can ask to see a dietitian or specialist nurse at your hospital. They can give you advice on improving your appetite and keeping to a healthy weight. You might find our section on eating well useful.
Pemetrexed can cause diarrhoea. This can usually be easily controlled with medicine, but tell your doctor if it's severe or continues. It's important to drink plenty of fluids if you have diarrhoea.
Pemetrexed can cause a rash, which may be itchy. Your doctor can prescribe medicine to help. To help prevent or reduce skin reactions, the steroid dexamethasone should be given with each treatment. The steroid is usually taken for three days starting on the day before pemetrexed is given.
Less common side effects
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It's very unusual to lose your hair. Some people notice that their hair becomes a little thinner, but not usually enough to be noticeable to other people.
You may get constipated. This can usually be helped by drinking plenty of fluids, eating more fibre and doing some exercise. You may need to take medicine (laxatives) to help. Your doctor can prescribe these or you can buy them at a pharmacy.
Treatment with pemetrexed may cause changes in the way your liver works, although it will return to normal when the treatment finishes. You're very unlikely to notice any problems, but your doctor will take regular blood samples to check your liver is working properly.
It’s important to let your doctor know straight away if you feel unwell or have any severe side effects, even if they’re not mentioned above.
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While you are receiving pemetrexed, it's best you don't use any folic acid supplements other than those prescribed by your cancer specialist.
Some multivitamins or food supplements also contain folic acid so it’s best to check with your chemist before taking these.
Risk of developing a blood clot
Cancer can increase the risk of developing a blood clot (thrombosis), and chemotherapy may increase this risk further.
A blood clot may cause symptoms such as pain, redness and swelling in a leg, or breathlessness and chest pain. Blood clots can be very serious, so it’s important to tell your doctor straight away if you notice any of these symptoms. Most clots can be treated with drugs that thin the blood. The doctor or nurse can give you more information.
Some medicines, including those you can buy in a shop or chemist, can be harmful to take when you're having chemotherapy. Tell your doctor about any medicines you're taking, including over-the-counter drugs, complementary therapies and herbal drugs.
You should tell your doctor if you're taking any medicines for pain or inflammation. These are called non-steroidal anti-inflammatory drugs (NSAIDs). NSAIDs, such as ibuprofen, can sometimes increase the side effects of pemetrexed. Your doctor will tell you which medicines you can take and the best times to take them.
Your ability to become pregnant or father a child may be affected by having this treatment. It's important to discuss fertility with your doctor before starting treatment.
It's not advisable to become pregnant or father a child while taking pemetrexed as it may harm the developing baby. It's important to use effective contraception while taking this drug and for at least a few months afterwards. You can discuss this with your doctor or nurse.
It’s not known whether chemotherapy drugs can be present in semen or vaginal fluids. To protect your partner, it’s safest to either avoid sex or use a barrier form of contraception for about 48 hours after chemotherapy.
If you’re admitted to hospital for a reason not related to the cancer, it’s important to tell the doctors and nurses looking after you that you're having chemotherapy treatment. You should tell them the name of your cancer specialist so that they can ask for advice.
It’s a good idea to know who you should contact if you have any problems or troublesome side effects when you’re at home. Your chemotherapy nurse or doctor will give you details of who to contact for advice. This should include ‘out-of hours’ contact details if you need to call someone at evenings, overnight or at the weekend.
This section is based on our pemetrexed fact sheet, which has been compiled using information from a number of reliable sources, including:
Sweetman, et al. Martindale: The Complete Drug Reference. 37th edition. 2011. Pharmaceutical Press.
British National Formulary. 62nd edition. 2011. British Medical Association and Royal Pharmaceutical Society of Great Britain.
electronic Medicines Compendium (eMC). www.medicines.org.uk (accessed October 2011).
Perry MC. The Chemotherapy Source Book. 4th edition. 2007. Lippincott Williams and Wilkins.