NCI Drug Dictionary

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The NCI Drug Dictionary contains technical definitions and synonyms for drugs/agents used to treat patients with cancer or conditions related to cancer. Each drug entry includes links to check for clinical trials listed in NCI's List of Cancer Clinical Trials.

botulinum toxin type A
An injectable formulation of a neurotoxin derived through the fermentation of the Hall strain of Clostridium botulinum type A with neuromuscular transmission inhibitory and analgesic activities. Upon injection into the affected muscle, the heavy chain portion of onabotulinumtoxinA binds to the cell membrane of the motor nerve and is internalized via endocytosis. Upon entry, the light chain portion of the toxin is activated and cleaves the protein SNAP-25, thereby preventing the fusion of acetylcholine (ACh)-containing synaptic vesicles with the cell membrane and, so, the release of ACh into the neuromuscular junction; subsequent binding of ACH to motor end-plate nicotinic acid receptors and ACh-mediated muscle contraction are thus blocked. In addition to ACh, onabotulinumtoxinA may inhibit the release of neuropeptides, such as substance P and glutamate, which may contribute to its analgesic activity. Check for active clinical trials using this agent. (NCI Thesaurus)
botulinum A toxin
botulinum neurotoxin type A
botulinum toxin A
US brand names:BOTOX
Botox cosmetic