Velbastine Mechanism of Action

Pharmacology: Pharmacodynamics: Although the mechanism of action has not been definitely established, vinblastine appears to bind to or crystallise critical microtubular proteins of the mitotic spindle, thus preventing their proper polymerisation and causing metaphase arrest. In high concentrations, vinblastine also exerts complex effects on nucleic acid and protein synthesis. Vinblastine reportedly also interferes with amino acid metabolism by blocking cellular utilisation of glutamic acid and thus inhibits purine synthesis, the citric acid cycle, and the formation of urea. Vinblastine exerts some immunosuppressive activity.
Pharmacokinetics: Vinblastine sulfate is unpredictably absorbed from the GI tract. Following intravenous administration, the drug is rapidly cleared from the blood and distributed into body tissues.
Vinblastine crosses the blood-brain barrier poorly and does not appear in the CSF in therapeutic concentrations. Vinblastine is reported to be extensively metabolised, primarily in the liver, to desacetylvinblastine, which is more active than the parent compound on a weight basis. The drug is excreted slowly in urine and in faeces via the bile.