methotrexate sodium: prescribing and clinical use
Focused clinical detail for use alongside current product information, local policy and patient-specific assessment.
methotrexate sodium: clinical details
Prescribing considerations
- Confirm indication, specialist oversight and ability to follow prescribed treatment.
- Review renal and hepatic function, blood count, infection status, vaccination needs, pregnancy potential and interacting medicines.
- Provide the methotrexate patient card and counsel about overdose and early toxicity symptoms.
Contraindications and cautions
- Hypersensitivity to methotrexate or product excipients
- Pregnancy for non-oncology indications and breastfeeding
- Severe hepatic or renal impairment
- Serious blood-cell disorders or significant immunodeficiency
- Active serious infection
- Oral or gastrointestinal ulceration
- Concurrent live vaccination
- Concurrent trimethoprim or co-trimoxazole in the selected product information
Monitoring
- Before treatment, assess full blood count, liver and renal function; consider viral screening and assessment for lung disease.
- Repeat full blood count, liver and renal tests after initiation or treatment changes, then continue risk-based surveillance.
- Interpret trends as well as absolute results; falling blood counts or albumin and rising transaminases or creatinine can indicate toxicity.
- Promptly investigate new mouth ulcers, infection, bruising, bleeding, cough or breathlessness.
Clinical pharmacology
Methotrexate is a folate antagonist and antimetabolite. Inhibition of folate-dependent nucleotide synthesis limits cell replication, while additional immunomodulatory actions contribute to anti-inflammatory effects. Renal elimination makes impaired kidney function and interacting medicines important determinants of toxicity.
Formulation and product differences
- The selected product is an oral tablet containing methotrexate sodium equivalent to methotrexate and includes lactose.
- Oral liquid and subcutaneous or injectable products have different administration requirements and must not be substituted without explicit instructions.
- Cancer treatment may use different formulations under specialist hospital protocols.
methotrexate sodium interactions
Check all prescribed, over-the-counter and complementary products with a pharmacist or prescriber. Important examples include:
Trimethoprim or co-trimoxazole
Avoid concurrent use where possible because combined antifolate effects can cause severe bone-marrow suppression.
NSAIDs, including ibuprofen, naproxen and analgesic aspirin
They can reduce renal elimination and increase kidney injury and methotrexate toxicity.
Penicillin antibiotics, including amoxicillin
They may reduce methotrexate clearance and increase toxicity; monitoring and toxicity counselling may be required.
Sources
These sources were used to prepare and review this medicine page.
Prepared and reviewed by the iatroX editorial team.