Moracizine

ATC codePharmacokinetic dataBioavailability34–38%Protein binding95%Elimination half-life3–4 hours (healthy volunteers), 6–13 hours (cardiac disease)IdentifiersCAS NumberPubChem CIDIUPHAR/BPSDrugBankChemSpiderUNIIKEGGChEBIChEMBLCompTox Dashboard (EPA)ECHA InfoCard100.046.216 Chemical and physical dataFormulaC₂₂H₂₅N₃O₄SMolar mass427.52 g·mol⁻¹3D model (JSmol)

Moracizine^[1] or moricizine, sold under the trade name Ethmozine, is an antiarrhythmic of class IC.^[2] It was used for the prophylaxis and treatment of serious and life-threatening ventricular arrhythmias,^[3] but was withdrawn in 2007 for commercial reasons.^[4]

Moracizine, a phenothiazine derivative, undergoes extensive first-pass metabolism and is also extensively metabolized after it has entered the circulation. It may have pharmacologically active metabolites. A clinical study has shown that moracizine is slightly less effective than encainide or flecainide in suppressing ventricular premature depolarizations.^{[citation needed]} Compared with disopyramide and quinidine, moracizine was equally or more effective in suppressing premature ventricular contractions, couplets, and nonsustained ventricular tachycardia.^{[citation needed]}

In the Cardiac Arrhythmia Suppression Trial (CAST), a large study testing the influence of antiarrhythmics on mortality, showed a statistically non-significant increase of mortality from 5.4 to 7.2% under moracizine. This is in line with other class IC antiarrhythmics.^[5]

The reaction between N-phenyl-1,3-benzenediamine (1) and ethyl chloroformate (2) gives the carbamate (3). Treatment with sulfur and iodine forms the phenothiazine derivative (4). Amide formation with 3-chloropropionyl chloride (5) gives the penultimate intermediate (6). Alkylation of morpholine by nucleophilic substitution at the sidechain chlorine yields moricizine.^[6][7]

• Ethacizine