Read the Patient Information Leaflet if available from your pharmacist before you start receiving pemetrexed and each time you receive a dose. If you have any questions, ask your doctor or pharmacist.

This medication is given by injection into a vein by a healthcare professional. It is given over 10 minutes as directed by your doctor, usually once every 3 weeks. The dosage is based on your medical condition, body size, and response to treatment. To lower your chance of having a skin reaction while using pemetrexed, your doctor will prescribe a corticosteroid medicine (such as dexamethasone) to take for a short period around the time of each treatment. Consult your doctor or pharmacist for more details.

To lower your chance of other side effects, it is very important that you take folic acid vitamins and receive vitamin B12 shots before and during treatment with pemetrexed. Folic acid vitamins are available over-the-counter without a prescription, and folic acid can be found in many multivitamin products. Make sure your vitamin contains between 400 to 1000 micrograms (0.4 to 1 milligram) of folic acid. Take folic acid daily starting 1 week before your first dose of pemetrexed, during treatment, and for 3 weeks after your last dose of pemetrexed. If you need help choosing a folic acid vitamin, ask your doctor or pharmacist. Your doctor will give you a vitamin B12 shot into the muscle, usually 1 week before your first dose of pemetrexed and then once every 9 weeks during your treatment. Do not substitute vitamin B12 taken by mouth for the vitamin B12 shots. Consult your doctor or pharmacist for more details.