Pemetrexed Injection

Category: Antineoplastic / Chemotherapy drug (Antifolate)
Form: Injectable solution for intravenous (IV) use

Uses:

• Treatment of malignant pleural mesothelioma (in combination with cisplatin).

• Treatment of non-small cell lung cancer (NSCLC), particularly non-squamous types, often in combination with other chemotherapy drugs.

• Can be used as maintenance therapy in certain NSCLC cases.

Mechanism of Action:

• Pemetrexed is an antifolate chemotherapeutic agent.

• Inhibits several enzymes involved in folate metabolism, including:

  • Thymidylate synthase

  • Dihydrofolate reductase

  • Glycinamide ribonucleotide formyltransferase

• This blocks DNA and RNA synthesis, preventing cancer cells from replicating and leading to cell death.

• Targets rapidly dividing tumor cells while sparing most normal cells.

Administration:

• Administered intravenously over 10 minutes or as specified in the protocol.

• Often given every 3 weeks, usually in combination with cisplatin or as monotherapy for maintenance.

• Pre-medication with folic acid, vitamin B12, and corticosteroids is recommended to reduce toxicity.

Side Effects:

• Hematologic: neutropenia, anemia, thrombocytopenia.

• Gastrointestinal: nausea, vomiting, diarrhea, mucositis.

• Other: fatigue, rash, liver enzyme elevation, fever.

• Rarely: severe myelosuppression or allergic reactions.

Precautions:

• Monitor blood counts, liver function, and renal function during therapy.

• Supplement with folic acid and vitamin B12 to reduce hematologic and gastrointestinal toxicity.

• Adjust dosage in patients with renal impairment.

Summary:
Pemetrexed Injection is an antifolate chemotherapy drug used primarily for malignant pleural mesothelioma and non-squamous non-small cell lung cancer. It inhibits key enzymes in folate metabolism, blocking DNA and RNA synthesis, and leading to cancer cell death. Administered intravenously every three weeks, it requires pre-medication with vitamins to reduce toxicity. Side effects include low blood counts, gastrointestinal issues, fatigue, and rare severe reactions.