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Alimta

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Alimta

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Pemetrexed

Method of action: Antitumour

Treatment option: Malignant Pleural Mesothelioma, Mesothelioma, Pleural Mesothelioma, Small Cell Lung Cancer, Non-Small Cell Lung Cancer, Cancer, Cancer,Lung, Chemotherapy

Medically reviewed

Marina Burgos

Last updated on 10/01/2026

This page provides general, reference-level information compiled from official medical sources. It is not a substitute for professional medical advice, diagnosis, or treatment. For decisions about your health, please consult a qualified healthcare professional.

Overview of Alimta

Property	Description
Active ingredient	Pemetrexed disodium
Form	Sterile lyophilized powder for solution for infusion
Pharmacological class	Antineoplastic Agent, Folate Analog Metabolic Inhibitor
Common use	Treatment for diseases involving uncontrolled cell replication
Origin	Synthetic compound

Pemetrexed: A Synthetic Antimetabolite and Folate Analog

Alimta is the trade name for the generic prescription medication Pemetrexed, officially classified as an antineoplastic agent—a drug designed to interrupt and slow the growth of problematic cells. Pemetrexed disodium is a synthetic compound that belongs to the pharmacological class of antimetabolites and is specifically identified as a folate analog metabolic inhibitor. This means the drug structurally mimics folic acid, allowing it to interfere with the cell’s internal machinery that relies on that vitamin for growth. This mechanism is recognized for its role in suppressing proliferation, a key feature of its pharmacological strategy.

Form and Composition of the Medication

The medication is supplied as a sterile, lyophilized powder for concentrate for solution for infusion, and is exclusively administered via intravenous (IV) infusion in a clinical setting. This preparation is a distinct feature of Pemetrexed, reflecting the need for precise, controlled systemic delivery. The active ingredient is Pemetrexed disodium. This formulation is administered intravenously because its action requires controlled systemic delivery. The final solution is prepared by mixing the powder, which includes excipients like mannitol, with a simple sterile vehicle such as 0.9% Sodium Chloride Injection.

The General Principle of its Therapeutic Purpose

The overall therapeutic purpose of Pemetrexed is to restrict the ability of rapidly dividing cells to grow and multiply uncontrollably. It accomplishes this by acting as a multi-targeted metabolic inhibitor, blocking the activity of several key enzymes necessary for the creation of new DNA and RNA. By impeding the formation of the essential genetic material required for cell reproduction, Pemetrexed works generally to control or slow the progression of diseases driven by rapid, uncontrolled cell replication.

Regulatory References

What side effects are possible with Alimta?

Possible side effects and safety information

Pemetrexed, as an antineoplastic agent, is associated with a range of officially documented adverse reactions that primarily affect systems with high cellular turnover, such as the blood and digestive systems. The overall safety profile is formally classified based on frequency, with certain events identified as serious adverse reactions in regulatory documents.

General Safety Patterns and High-Frequency Adverse Reactions

The most frequently reported adverse reactions are centered on Blood and Lymphatic System Disorders (myelosuppression) and Gastrointestinal Disorders. The most common adverse reactions, defined as those with a regulatory incidence of 20% or greater when Pemetrexed is administered alone, include fatigue/asthenia, nausea, and anorexia (decreased appetite). When used in combination, high-frequency events also include neutropenia, anemia, vomiting, and stomatitis/pharyngitis (mouth/throat inflammation). The risk and severity of these toxicities are notably increased in patients who do not receive adequate prophylactic supplementation with folic acid and vitamin B12.

Documented Serious Adverse Reactions and Physiological Constraints

Adverse reactions classified as serious or life-threatening in official labeling span several organ systems. These include severe and sometimes fatal renal failure, severe bone marrow suppression, and life-threatening bullous and exfoliative skin toxicity. Due to the drug’s elimination pathway, a baseline measure of sufficient renal function (Creatinine Clearance ge 45 mL/min) is a formal constraint for administration. Additionally, the label documents the risk of the Radiation Recall Phenomenon—a skin reaction that can reappear in a previously irradiated area, sometimes weeks to years later. Use of the medicine is not recommended for individuals with severe renal impairment, and it can cause fetal harm, which represents a specific safety constraint for reproductive health.

Overdose and Emergency Response

Overdose and When to Seek Help

The regulatory documents for Pemetrexed (Alimta) define an overdose profile characterized by an exacerbation of its dose-limiting toxicities. This situation is considered potentially severe or life-threatening and requires immediate professional medical intervention.

Documented Overdose Manifestations

Overdosage has been reported following the administration of doses higher than those recommended. The primary documented manifestations relate to severe bone marrow suppression, resulting in conditions such as neutropenia, anemia, and thrombocytopenia. This severe impact on the hematopoietic system creates a risk for consequential infection. Other manifestations reported in the regulatory label include mucositis, diarrhea, and rash, along with potential sensory polyneuropathy.

Emergency Actions and Risk Factors

Due to the risk of severe myelosuppression and associated infection, immediate medical attention is required upon suspicion of an overdose. Management is centered on monitoring and supportive care. Patients must be monitored with blood counts to determine the level of toxicity. The official label notes that the use of folinic acid or calcium folinate may be considered by healthcare professionals to mitigate the toxic effects, although no specific antidote is approved. A critical population-related risk exists for patients with impaired renal function, as decreased renal clearance leads to significantly increased systemic drug exposure and risk of severe toxicity.

Therapeutic Uses of Alimta

What Alimta Treats: Main Uses and Benefits

Pemetrexed is used in the management of locally advanced or metastatic Non-Small Cell Lung Cancer (NSCLC), specifically the non-squamous subtype, and Malignant Pleural Mesothelioma (MPM). It is considered relevant when the disease is widespread or unresectable for surgery alone, and is relevant in the therapeutic plan for these challenging thoracic malignancies.

The central goal of treatment with Pemetrexed is to support disease stabilization and control. This therapeutic domain involves managing conditions where functional stability becomes affected, such as advanced NSCLC or MPM. The treatment supports general well-being and is commonly used to help manage the progression of the condition.

Pemetrexed plays a role in managing the distressing symptoms that create noticeable physiological strain directly resulting from the cancer’s presence and expansion. This is relevant for easing symptoms related to physical discomfort, such as pain, cough, and shortness of breath (dyspnea) caused by the tumor.

Quick Fact: Relief for Tumor-Related Respiratory Impairment

Eligibility and Restrictions for Use

Eligibility for Alimta (Pemetrexed) — Official Regulatory Information

Alimta is approved for use in adult patients with unresectable malignant pleural mesothelioma (MPM) and non-squamous non-small cell lung cancer (NSCLC). Use in the pediatric population (children and adolescents) is not established by regulatory agencies.

Absolute Contraindications	Conditional Restrictions
Patients with a history of severe hypersensitivity to Pemetrexed.	Patients must have adequate blood counts before each cycle: Absolute Neutrophil Count 1500 cells/mm^3 and Platelets 100,000 cells/mm^3.
Breastfeeding women (contraindicated during treatment and for one week after the final dose).	Patients with severe renal impairment (Creatinine Clearance <45 mL/min) are not recommended to receive treatment.
Concomitant receipt of Yellow Fever Vaccine.	Use in the squamous cell NSCLC subtype is not indicated.

Pregnancy Status Use of Pemetrexed should be avoided during pregnancy due to the potential for fetal harm. Both male and female patients of reproductive potential are advised to use effective contraception during and for a required period following treatment.

What should I know about interactions with other medicines?

Alimta (pemetrexed) has documented interaction patterns primarily concerning its renal elimination and compatibility with vaccines, as noted in official regulatory labeling.

Interacting Products and Constraints

Classification	Interacting Substances / Categories
Formal Contraindication	Yellow Fever Vaccine (Live) (Non-US regulatory labels)
Exposure-Altering Drugs	NSAIDs with a short half-life (e.g., Ibuprofen), Nephrotoxic drugs, Substances secreted at the renal tubule (e.g., Probenecid), High-dose Acetylsalicylic acid (>1.3 g daily)
Procedural Requirement	Oral Folic Acid and Intramuscular Vitamin B12 (Mandated co-treatment to reduce toxicity)

Co-administration of drugs that are tubularly secreted or have a nephrotoxic effect may result in delayed clearance of pemetrexed, increasing systemic exposure. The combination of pemetrexed with NSAIDs like ibuprofen is officially noted to reduce pemetrexed clearance by about 20%.

Timing Separation Rules

For patients with mild to moderate renal insufficiency (creatinine clearance 45 mL/min - 79 mL/min), regulatory documents mandate that NSAIDs with a short half-life must be avoided for 2 days before, the day of, and 2 days following pemetrexed administration. Administration of other Live Attenuated Vaccines is generally restricted due to the potential for systemic disease.

Mechanism of Action

How Pemetrexed Works: The Mechanistic Basis

The mechanism of Pemetrexed begins with its transport into the cell, primarily by the Reduced Folate Carrier (RFC), followed by mandatory intracellular activation via the enzyme Folylpolyglutamate Synthetase (FPGS). The resulting active forms act as competitive inhibitors of three folate-dependent enzymes: Thymidylate Synthase (TS), Dihydrofolate Reductase (DHFR), and Glycinamide Ribonucleotide Formyltransferase (GARFT). This initial molecular action establishes the multi-faceted folate antagonism mechanism.

The simultaneous inhibition of these enzymes impairs the synthesis of both purine and pyrimidine nucleotides, the necessary precursors for genetic material. Specifically, blocking TS halts the creation of deoxythymidylate (dTMP), while blocking GARFT impairs the overall pathway for purine synthesis. This dual blockade creates an unbalanced nucleotide pool and subsequent DNA damage, which leads to the eventual physiological consequence of apoptosis (programmed cell death) in cells with a high proliferative rate.

This functional activity is intrinsically tied to biological constraints. The mechanism is limited when cells exhibit resistance factors, such as the upregulation of the primary target enzyme, TS, or reduced expression of the necessary drug carriers.

Dosage and Administration Information

How Alimta (Pemetrexed) is Used: Administration Guidelines

Alimta (Pemetrexed) is an anti-cancer medication with a specific usage protocol. The medicine is exclusively administered by Intravenous (IV) Infusion in a clinical setting. It is supplied as a sterile lyophilized powder that must be reconstituted and diluted using a specific fluid, 0.9% Sodium Chloride Injection; use of calcium-containing diluents is prohibited.

Standard Dosing and Schedule

The standard adult dose for Pemetrexed is 500 mg/m^2 (milligrams per square meter of body surface area). The drug is administered once every 21-day cycle, with the infusion taking place over a 10-minute period on Day 1. When used in combination with Cisplatin, the Cisplatin is typically administered 30 minutes following the completion of the Pemetrexed infusion.

Mandatory Premedication Requirements

Proper use requires adherence to a strict, multi-agent premedication regimen surrounding the infusion day. Patients must receive oral Folic Acid (daily, starting at least 7 days before the first dose and continuing throughout treatment) and an Intramuscular Vitamin B12 injection (given one week before the first dose and every three cycles thereafter). Additionally, an oral corticosteroid (such as Dexamethasone) must be given twice daily for three consecutive days: the day before, the day of, and the day after Pemetrexed administration.

Procedural Constraints

The initiation of a new cycle is conditional on the recovery of blood counts, and treatment must be delayed if specific thresholds are not met. Furthermore, Pemetrexed is not administered to patients whose Creatinine Clearance (a measure of kidney function) is below 45 mL/min.

Recent Clinical Evidence

Alimta: Recent Clinical Evidence

Alimta (pemetrexed) is a chemotherapy agent used in the treatment of specific types of cancer, primarily non-small cell lung cancer (NSCLC) and malignant pleural mesothelioma. Clinical research studies continue to examine its role, particularly in combination therapies.

Combination Therapy in Advanced NSCLC

Recent large-scale clinical trials (e.g., KEYNOTE-189) explored the use of a combination regimen that included pemetrexed, a platinum-based agent (such as cisplatin or carboplatin), and an immunotherapy drug (pembrolizumab) as a first-line treatment for advanced non-squamous NSCLC. Studies reported that this combination was associated with changes in overall survival (OS) and progression-free survival (PFS) compared to chemotherapy alone, regardless of the patient's PD-L1 expression level.

Role in Maintenance Therapy

Research has investigated the benefits of continuing pemetrexed after initial induction chemotherapy for advanced non-squamous NSCLC that has not progressed. Studies, such as the PARAMOUNT trial, explored whether maintenance therapy with pemetrexed, compared to placebo, was associated with prolonged progression-free survival and overall survival in individuals whose disease remained stable after initial platinum-based treatment.

Efficacy Comparison and Tolerability

Studies have included a comparison group receiving other non-biologic agents. For instance, in second-line treatment of advanced NSCLC, clinical trials examined outcomes for pemetrexed versus docetaxel. These studies reported clinically similar efficacy outcomes between the two agents, while noting differences in the profiles and frequencies of reported side effects, such as myelosuppression (low blood counts) and specific non-hematologic toxicities.

Note: Research across all indications has demonstrated the importance of vitamin B12 and folic acid supplementation in individuals receiving pemetrexed to help manage associated hematologic and gastrointestinal side effects.

Frequently Asked Questions (FAQ)

Common questions about Alimta (FAQ)

Q: What is Alimta used for?

Alimta (pemetrexed) is a chemotherapy medication used to treat certain types of malignant pleural mesothelioma and non-small cell lung cancer (NSCLC). Its specific use depends on the cancer stage, type of NSCLC, and whether it is being used in combination with other treatments like cisplatin.

Q: How is Alimta administered?

Alimta is administered into a vein (intravenously or IV) by a healthcare professional in a clinical setting. It is typically given as an infusion over approximately 10 minutes. The prescribed treatment schedule, including the frequency and duration of cycles, is determined by the treating physician.

Q: Are there any required pre-treatments before receiving Alimta?

Yes, patients receiving Alimta must typically receive vitamin B12 and folic acid supplements starting before the first dose. This regimen is required to help reduce the risk of specific side effects associated with the medication. A corticosteroid medication may also be prescribed to help prevent certain skin reactions.

Q: What are the most common side effects of Alimta?

The official prescribing information indicates that common side effects can include nausea, vomiting, fatigue, loss of appetite, and changes in blood cell counts (e.g., low white blood cells, low red blood cells, or low platelets). Monitoring blood cell counts is a standard part of the treatment process.

How should Alimta be stored and disposed of?

The storage and disposal of Alimta (pemetrexed) must strictly follow regulatory standards due to its nature as a cytotoxic drug.

Official Storage Conditions

Product Form	Temperature Range	Additional Requirement
Lyophilized Powder (Unopened)	Controlled Room Temperature (20 C to 25 C)	Store in the original carton to protect from light.
Reconstituted/Diluted Solution	Refrigerated (2 C to 8 C)	Do not freeze. Must be discarded after 24 hours from initial reconstitution.

All portions of the medicine must be kept out of the sight and reach of children.

Handling and Disposal

Alimta is classified as a hazardous medicinal product. Any unused product, including vials and waste materials, must be handled and disposed of according to local regulatory procedures for cytotoxic waste. It should not be disposed of in general household trash or wastewater.

Attention! Always consult to a doctor or pharmacist before using pills or medicines.