Tacrine (TCR)

Tacrine is a centrally acting anticholinesterase and indirect cholinergic agonist (parasympathomimetic). It was the first centrally-acting cholinesterase inhibitor approved for the treatment of Alzheimer's disease. It also acts as a histamine N-methyltransferase inhibitor. Tacrine was the prototypical cholinesterase inhibitor for the treatment of Alzheimer's disease. Studies found that it may have a small beneficial effect on cognition and other clinical measures, though study data was limited and the clinical relevance of these findings was unclear. As stated above, overdosage of tacrine may give rise to severe side effects such as nausea, vomiting, salivation, sweating, bradycardia, hypotension, collapse, and convulsions. Atropine is a popular treatment for overdose. Major form of metabolism is in the liver via hydroxylation of benzylic carbon by CYP1A2. This forms the major metabolite 1-hydroxy-tacrine (velnacrine) which is still active.