antimitotics

Antimitotics are a class of drugs that inhibit mitosis by targeting the mitotic spindle, primarily microtubules. They are cytotoxic chemotherapy agents used to treat cancer.

Major classes include vinca alkaloids, taxanes, and other microtubule-targeting agents. Vinca alkaloids such as vincristine, vinblastine, and vinorelbine bind to tubulin and prevent polymerization, causing spindle defects and metaphase arrest. Taxanes, including paclitaxel, docetaxel, and cabazitaxel, stabilize microtubules and prevent their disassembly, also leading to mitotic arrest. Other agents acting on microtubules include epothilones like ixabepilone and colchicine-site inhibitors.

They are used in a variety of cancers, often as part of combination regimens. Administration is typically intravenous, and dosing decisions depend on tumor type, prior therapies, and observed toxicities.

Common adverse effects include myelosuppression, neuropathy, fatigue, alopecia, and mucositis. Specific toxicities differ by agent (for example, neuropathy is prominent with several vinca alkaloids and taxanes). Development of resistance can involve tubulin mutations, increased expression of drug efflux pumps, or changes in microtubule dynamics.

History and context: many antimitotics are natural products discovered in the 20th century. Vinca alkaloids are derived from Catharanthus roseus, while taxanes originate from yew trees, with subsequent semi-synthetic or synthetic derivatives expanding their use.