pemetrexed disodium hemipentahydrate: prescribing and clinical use
Focused clinical detail for use alongside current product information, local policy and patient-specific assessment.
pemetrexed disodium hemipentahydrate: clinical details
Prescribing considerations
- Confirm an adult, licensed tumour indication and appropriate non-squamous histology where treating non-small-cell lung cancer.
- Ensure folic acid and vitamin B12 supplementation and corticosteroid premedication are arranged.
- Review renal function, hydration, nephrotoxic medicines, NSAIDs and OAT3 inhibitors before administration.
- Consider management of significant pleural effusion or ascites and review previous or planned radiotherapy because pneumonitis and radiation recall have occurred.
- Discuss contraception and fertility preservation before treatment where relevant.
Contraindications and cautions
- Hypersensitivity to pemetrexed or an excipient.
- Breastfeeding.
- Concomitant yellow fever vaccination.
- Use is not recommended when creatinine clearance is below the product-supported threshold because clinical data are insufficient.
- Exercise caution with impaired renal function, dehydration, significant third-space fluid, cardiovascular risk or previous radiotherapy.
Monitoring
- Complete blood count with differential and platelets before administration.
- Renal and hepatic biochemistry before administration and during treatment.
- Clinical toxicity, including infection, mucositis, gastrointestinal effects, rash, neuropathy and renal symptoms.
- Hydration and signs of tubular injury or nephrogenic diabetes insipidus.
- INR more frequently when an oral anticoagulant is continued.
Clinical pharmacology
Pemetrexed is intracellularly polyglutamated and inhibits several folate-dependent enzymes involved in thymidine and purine synthesis. It undergoes limited hepatic metabolism and is eliminated mainly unchanged through the kidneys, including OAT3-mediated tubular secretion.
Formulation and product differences
- The selected product is a ready-made concentrate that requires dilution before intravenous infusion rather than a powder requiring reconstitution.
- It contains sodium and propylene glycol; quantities vary with vial size.
- It is incompatible with calcium-containing diluents such as Ringer's and lactated Ringer's solutions.
- Vials are for single use and unused cytotoxic material requires appropriate disposal.
pemetrexed disodium hemipentahydrate preparations and strengths
Solution for infusion
Route: Intravenous
Strengths: 25 mg/mL
pemetrexed disodium hemipentahydrate interactions
The oncology team should review all medicines, vaccines and supplements before treatment.
NSAIDs and high-dose aspirin
These may reduce renal elimination of pemetrexed and increase bone-marrow and gastrointestinal toxicity, particularly when kidney function is impaired.
Nephrotoxic medicines
Aminoglycosides, loop diuretics, platinum compounds and ciclosporin may delay pemetrexed clearance, so kidney function may require closer monitoring.
OAT3 inhibitors
Probenecid, penicillins and proton-pump inhibitors may delay pemetrexed clearance; assess the combination and monitor for toxicity.
Sources
These sources were used to prepare and review this medicine page.
Prepared and reviewed by the iatroX editorial team.