Ethopropazine is a butyrylcholinesterase (BChE) inhibitor (IC₅₀= 15.14 µM in human erythrocyte lysates).¹It is selective for BChE over acetylcholinesterase (AChE) at 500 µM. Ethopropazine also binds to rat forebrain and hindbrain membrane preparations (K_is = 3.1 and 7.2 nM, respectively), which are endogenously enriched in M₁and M₂muscarinic acetylcholine receptors, respectively.²Ethopropazine (0.232 mg/kg) decreases the intensity and increases the latency of haloperidol-induced catalepsy, a model of extrapyramidal syndrome, in rats when used in combination with the adenosine A_2Areceptor antagonist ZM 241395 .³It reduces thermal hyperalgesia in a rat model of neuropathic pain induced by sciatic nerve ligation when administered at doses of 20 and 30 mg/kg.⁴Formulations containing ethopropazine were previously used in the treatment of Parkinson's disease.

1.Ucar, G., Gokhan, N., Yesilada, A., et al.1-N-Substituted thiocarbamoyl-3-phenyl-5-thienyl-2-pyrazolines: a novel cholinesterase and selective monoamine oxidase B inhibitors for the treatment of Parkinson's and Alzheimer's diseasesNeurosci. Lett.382(3)327-331(2005) 2.Burke, R.E.The relative selectivity of anticholinergic drugs for the M1 and M2 muscarinic receptor subtypesMov. Disord.1(2)135-144(1986) 3.GonzÁlez-Lugo, O.E., Ceballos-Huerta, F., JimÉenez-Capdeville, M.E., et al.Synergism of theophylline and anticholinergics to inhibit haloperidol-induced catalepsy: A potential treatment for extrapyramidal syndromesProg. Neuropsychopharmacol. Biol. Psychiatry34(8)1465-1471(2010) 4.Jevtovic-Todorovic, V., Meyenburg, A.P., Olney, J.W., et al.Anti-parkinsonian agents procyclidine and ethopropazine alleviate thermal hyperalgesia in neuropathic ratsNeuropharmacology44(6)739-748(2003)