| Half-life | 8 hours |
| Clearance Route | renal |
| Active Metabolites | yes |
| Notes | High-dose MTX requires leucovorin rescue AND vigorous hydration + alkalinization of urine. |
Severity: Severe
Adverse Effects:
Myelosuppression, hepatotoxicity, mucositis, nephrotoxicity at high dose
Contraindications:
Pregnancy, chronic liver disease, severe renal impairment
Precautions:
Monitor CBC + LFTs; avoid NSAIDs around HD-MTX; leucovorin rescue mandatory for high dose
(this is for anticancer/high-dose range, low RA dosing pharmacokinetics is different, but we keep 8h for oncologic use)