About vincristinenatural (vinca) alkaloid, a mitotic inhibitor, antineoplastic.mechanism of action of vincristinevincristine binds to the tubuline dimers (tubuline is a structural protein which polymerizes to form microtubules) and inhibit the polymerization causing disassembly of microtubule structure. disruption of the microtubules arrests mitosis in metaphase. it also inhibits dna-dependant rna synthesis and purine synthesis.interactions for vincristinedigoxin: decreased plasma digoxin levels and renal excretion. l-asparaginase: hepatic clearance of vincristine is reduced if l-asparaginase is administered first. thus to minimise toxicity, vincristine should be given 12 to 24 hours before administering l- asparaginase. mitomycin-c: acute pulmonary reaction may occur. phenytoin: reduced phenytoin plasma levels.