What is Pemetrexed: Uses, Dosage, Side Effects and More

Pemetrexed is a chemotherapy medication given through an IV to treat certain types of cancer, particularly lung cancer and mesothelioma. This powerful anti-cancer drug works by blocking cancer cells from making DNA and proteins they need to grow and divide.

If you or someone you care about has been prescribed pemetrexed, you likely have many questions about what to expect. Understanding how this medication works, its benefits, and potential side effects can help you feel more prepared and confident during treatment.

What is Pemetrexed?

Pemetrexed is a type of chemotherapy drug called an antifolate or antimetabolite. It's designed to interfere with cancer cells' ability to reproduce by blocking important chemical processes they need to survive.

This medication comes as a powder that your healthcare team mixes with sterile water to create a solution. The solution is then given slowly through a vein in your arm over about 10 minutes. You'll receive this treatment in a hospital or cancer center where trained professionals can monitor you closely.

Pemetrexed belongs to a class of medications that specifically target rapidly dividing cells, which is why it's effective against cancer. The drug essentially starves cancer cells of the nutrients they need to make new DNA and proteins.

What is Pemetrexed Used For?

Pemetrexed treats specific types of cancer, most commonly non-small cell lung cancer and malignant pleural mesothelioma. Your doctor has chosen this medication because it's particularly effective against these cancer types.

For lung cancer, pemetrexed is often used when the cancer has spread to other parts of the body or when other treatments haven't worked as well as hoped. It can be given alone or combined with other chemotherapy drugs, depending on your specific situation.

Mesothelioma, a cancer often linked to asbestos exposure, also responds well to pemetrexed treatment. In this case, the medication is typically combined with another drug called cisplatin to create a more powerful treatment approach.

Sometimes doctors also use pemetrexed as maintenance therapy. This means you might continue receiving it after your initial treatment to help prevent cancer from coming back or growing.

How Does Pemetrexed Work?

Pemetrexed works by blocking several enzymes that cancer cells need to make DNA and RNA. Think of these enzymes as essential tools in a cancer cell's survival toolkit.

When pemetrexed enters your body, it gets converted into an active form that looks similar to folate, a vitamin that cells need to function. However, instead of helping cells grow like real folate does, pemetrexed tricks the cancer cells and blocks their growth processes.

This medication is considered a strong chemotherapy drug. It affects rapidly dividing cells throughout your body, which is why it can cause side effects in healthy tissues that also divide quickly, like your hair follicles and the lining of your mouth and digestive tract.

The good news is that cancer cells are generally more sensitive to pemetrexed than normal cells. This means the medication tends to harm cancer cells more than it affects your healthy tissues.

How Should I Take Pemetrexed?

You don't actually "take" pemetrexed yourself since it's given through an IV by your healthcare team. However, there are important steps you need to follow to prepare for and support your treatment.

Before each pemetrexed treatment, you'll need to take folic acid supplements and vitamin B12 injections. These vitamins help protect your healthy cells from some of the medication's side effects. You'll typically start taking folic acid about a week before your first treatment and continue throughout your therapy.

Your doctor will also prescribe a corticosteroid medication like dexamethasone to take before each treatment. This helps reduce the risk of skin reactions and other side effects. You'll usually take this medication the day before, the day of, and the day after each pemetrexed infusion.

On treatment days, make sure to eat a light meal beforehand and stay well-hydrated. Bring comfortable clothes and perhaps some entertainment, as you'll be at the treatment center for several hours including preparation and monitoring time.

How Long Should I Take Pemetrexed For?

The length of your pemetrexed treatment depends on several factors, including your type of cancer, how well you're responding to treatment, and how you're tolerating the medication. Most people receive treatments every three weeks.

Your doctor will monitor your progress through regular scans, blood tests, and physical exams. If the cancer is responding well and you're tolerating the medication without serious side effects, you might continue treatment for several months.

Some people receive pemetrexed for four to six cycles initially, then switch to maintenance therapy if their cancer is stable or shrinking. Others might need treatment for a longer period, depending on how their cancer responds.

Your healthcare team will regularly reassess whether continuing pemetrexed is the best option for you. They'll consider factors like your overall health, quality of life, and whether the benefits of treatment outweigh the side effects you're experiencing.

What Are the Side Effects of Pemetrexed?

Like all chemotherapy medications, pemetrexed can cause side effects, though not everyone experiences them all. Understanding what to expect can help you feel more prepared and know when to contact your healthcare team.

The most common side effects you might experience include fatigue, nausea, loss of appetite, and changes in your blood counts. These effects happen because pemetrexed affects rapidly dividing cells throughout your body, not just cancer cells.

Here are the more common side effects you should be aware of:

• Fatigue and weakness that may last several days after treatment
• Nausea and vomiting, usually manageable with anti-nausea medications
• Decreased appetite and changes in taste
• Diarrhea or constipation
• Mouth sores or throat irritation
• Skin rash or sensitivity
• Hair thinning, though complete hair loss is less common than with other chemotherapy drugs

Your medical team will monitor you closely and provide medications to help manage these side effects. Most people find that symptoms improve between treatment cycles.

Some less common but more serious side effects require immediate medical attention. These include signs of infection like fever, severe skin reactions, difficulty breathing, or unusual bleeding or bruising.

Rare but serious side effects can include severe kidney problems, lung inflammation, or severe skin reactions. While these are uncommon, your healthcare team will monitor you carefully and teach you what warning signs to watch for.

Who Should Not Take Pemetrexed?

Pemetrexed isn't suitable for everyone, and your doctor will carefully evaluate whether it's the right choice for you. Certain health conditions or circumstances might make this medication too risky.

You shouldn't receive pemetrexed if you have a severe allergy to the medication or any of its ingredients. Your doctor will also be cautious if you have significant kidney problems, as pemetrexed is eliminated from your body through your kidneys.

People with severe liver disease, active infections, or very low blood cell counts might not be good candidates for pemetrexed treatment. Your doctor will run comprehensive blood tests before starting treatment to make sure your body can handle the medication safely.

If you're pregnant or breastfeeding, pemetrexed is not recommended as it can harm your developing baby. Both men and women should use effective birth control during treatment and for several months afterward.

Your doctor will also consider your overall health status, age, and other medications you're taking. Some drug interactions can make pemetrexed less effective or increase the risk of side effects.

Pemetrexed Brand Names

Pemetrexed is available under several brand names, with Alimta being the most well-known original brand. Your pharmacy or treatment center might use this name when discussing your medication.

Generic versions of pemetrexed are also available and work exactly the same way as the brand-name medication. These generic versions have the same active ingredient and effectiveness but may cost less.

Whether you receive brand-name or generic pemetrexed doesn't affect how well your treatment works. Your healthcare team will use whichever version is most appropriate and accessible for your situation.

Pemetrexed Alternatives

If pemetrexed isn't suitable for you or stops working effectively, your doctor has several other treatment options to consider. The best alternative depends on your specific type of cancer and your overall health.

For lung cancer, alternatives might include other chemotherapy drugs like carboplatin, paclitaxel, or docetaxel. Targeted therapy drugs or immunotherapy medications might also be options, depending on specific characteristics of your cancer.

For mesothelioma, alternatives could include combination chemotherapy with different drugs, radiation therapy, or surgery if your cancer is caught early enough. Clinical trials investigating new treatments might also be available.

Your oncologist will work with you to find the most appropriate treatment plan if pemetrexed isn't the right fit. They'll consider factors like your cancer type, stage, previous treatments, and your personal preferences.

Is Pemetrexed Better Than Cisplatin?

Pemetrexed and cisplatin work differently and are often used together rather than being compared as competing treatments. They're both effective chemotherapy drugs, but they have different strengths and side effect profiles.

Cisplatin is often considered one of the most effective chemotherapy drugs for certain cancers, but it can cause significant side effects like kidney damage, hearing loss, and nerve problems. Pemetrexed generally causes fewer of these specific side effects.

In many cases, your doctor might recommend using both medications together, as they can work better in combination than either drug alone. This approach, called combination chemotherapy, is common in treating lung cancer and mesothelioma.

The choice between these medications or using them together depends on your specific cancer type, your overall health, and your treatment goals. Your oncologist will help determine the best approach for your individual situation.