Classification: Antifolate Antineoplastic Agent
About: Pemetrexed (Alimta®)
Pemetrexed works by blocking three separate enzymes that cells need to replicate. These enzymes, needed for folate-dependent metabolic processes, are required for DNA replication. By blocking DNA production, cell growth and division is stopped, resulting in the slowing or stopping of cancer growth. Since cancer cells, in general, divide faster and with less error-correcting than healthy cells, cancer cells are more sensitive to this damage.
How to Take Pemetrexed
Pemetrexed is given by intravenous (IV) infusion. It is typically given once every 21 days. The dose is based on the patient’s height and weight. A steroid medication is often given before pemetrexed to decrease skin rash. Folic acid supplementation of 400 mcg to 1000 mcg should be given for at least 5 out of 7 days prior to the first dose of pemetrexed, throughout treatment and for three weeks after the last dose is given. An injection of vitamin B12 should be given before the first dose of pemetrexed, and then about every 9 weeks during treatment. These vitamin supplementations should decrease the side effects you experience. Speak with your provider concerning the specific dosing of steroids, folic acid and B12 and timing of these medications.
Let your healthcare provider know all medications, vitamins and supplements you are taking as some can interfere with pemetrexed. Be sure to notify your care provider if you take any form of NSAID (non-steroidal anti-inflammatory drug) such as aspirin or ibuprofen because, taken in conjunction with pemetrexed, can cause kidney problems.
Possible Side Effects of Pemetrexed
There are a number of things you can do to manage the side effects of pemetrexed. Talk to your care team about these recommendations. They can help you decide what will work best for you. These are some of the most common or important effects:
Low White Blood Cell Count (Leukopenia or Neutropenia)
White blood cells (WBC) are important for fighting infection. While receiving treatment, your WBC count can drop, putting you at a higher risk of getting an infection. You should let your doctor or nurse know right away if you have a fever (temperature greater than 100.4), sore throat or cold, shortness of breath, cough, burning with urination, or a sore that doesn't heal.
Tips to preventing infection:
- Washing hands, both yours and your visitors, is the best way to prevent the spread of infection.
- Avoid large crowds and people who are sick (i.e.: those who have a cold, fever or cough or live with someone with these symptoms).
- When working in your yard, wear protective clothing including long pants and gloves.
- Do not handle pet waste.
- Keep all cuts or scratches clean.
- Shower or bath daily and perform frequent mouth care.
- Do not cut cuticles or ingrown nails. You may wear nail polish, but not fake nails.
- Ask your oncology care team before scheduling dental appointments or procedures.
- Ask your oncology care team before you, or someone you live with, has any vaccinations.
Low Red Blood Cell Count (Anemia)
Your red blood cells are responsible for carrying oxygen to the tissues in your body. When the red cell count is low, you may feel tired or weak. You should let your oncology care team know if you experience any shortness of breath, difficulty breathing or pain in your chest. If the count gets too low, you may receive a blood transfusion.
Low Platelet Count (Thrombocytopenia)
Platelets help your blood clot, so when the count is low you are at a higher risk of bleeding. Let your oncology care team know if you have any excess bruising or bleeding, including nose bleeds, bleeding gums or blood in your urine or stool. If the platelet count becomes too low, you may receive a transfusion of platelets.
- Do not use a razor (an electric razor is fine).
- Avoid contact sports and activities that can result in injury or bleeding.
- Do not take aspirin (salicylic acid), non-steroidal, anti-inflammatory medications (NSAIDs) such as Motrin/Advil (ibuprofen), Aleve (naproxen), Celebrex (celecoxib) etc. as these can all increase the risk of bleeding. Please consult with your healthcare team regarding use of these agents and all over the counter medications/supplements while on therapy.
- Do not floss or use toothpicks and use a soft-bristle toothbrush to brush your teeth.
Nausea and/or Vomiting
Talk to your oncology care team so they can prescribe medications to help you manage nausea and vomiting. In addition, dietary changes may help. Avoid things that may worsen the symptoms, such as heavy or greasy/fatty, spicy or acidic foods (lemons, tomatoes, oranges). Try saltines, or ginger ale to lessen symptoms.
Call your oncology care team if you are unable to keep fluids down for more than 12 hours or if you feel lightheaded or dizzy at any time.
Decrease in Appetite
Nutrition is an important part of your care. Cancer treatment can affect your appetite and, in some cases, the side effects of treatment can make eating difficult. Ask your oncology care team about nutritional counseling services at your treatment center to help with food choices.
- Try to eat five or six small meals or snacks throughout the day, instead of 3 larger meals.
- If you are not eating enough, nutritional supplements may help.
- You may experience a metallic taste or find that food has no taste at all. You may dislike foods or beverages that you liked before receiving cancer treatment. These symptoms can last for several months or longer after treatment ends.
- Avoid any food that you think smells or tastes bad. If red meat is a problem, eat chicken, turkey, eggs, dairy products and fish without a strong smell. Sometimes cold food has less of an odor.
- Add extra flavor to meat or fish by marinating it in sweet juices, sweet and sour sauce or dressings. Use seasonings like basil, oregano or rosemary to add flavor. Bacon, ham and onion can add flavor to vegetables.
Fatigue is very common during cancer treatment and is an overwhelming feeling of exhaustion that is not usually relieved by rest. While on cancer treatment, and for a period after, you may need to adjust your schedule to manage fatigue. Plan times to rest during the day and conserve energy for more important activities. Exercise can help combat fatigue; a simple daily walk with a friend can help. Talk to your healthcare team for helpful tips on dealing with this side effect
Report any changes in your urinary habits, including a change in the amount or color of your urine. Be sure to notify your care provider if you take any form of NSAID (non-steroidal anti-inflammatory drug) such as aspirin or ibuprofen because, taken in conjunction with pemetrexed, can cause kidney problems.
These changes can include dryness, itching, and rash. Rash related to this medication typically occurs between doses and resolves before the next dose. A rash can result in blistering or peeling of the skin Use an alcohol free moisturizer on your skin and lips; avoid moisturizers with perfumes or scents. Your oncology care team can recommend a topical medication if itching is bothersome. If your skin does crack or bleed, be sure to keep the area clean to avoid infection. Be sure to notify your oncology care team of any rash that develops, as this can be a reaction.
Exposure of an unborn child to this medication could cause birth defects, so you should not become pregnant or father a child while on this medication. Effective birth control is necessary during treatment. Even if your menstrual cycle stops or you believe you are not producing sperm, you could still be fertile and conceive. Women should stop breastfeeding while on this medication because it is unknown if the medication can be passed through breast milk.