Last reviewed 01/2018

Piperadine compounds produce less extrapyramidal side effects than other phenothiazines and so often used in elderly patients.

They may produce pigmentation of the retina in some patients and should not be given in large doses for long periods.

The CSM has advised that the use of thioridazine should be restricted to the second line treatment of schizophrenia in adults (1):

  • this advice follows consideration of the rare but serious cardiotoxicity (QTc interval prolongation and life-threatening ventricular arrhythmias) associated with the treatment with thioridazine.
  • it has been advised that thioridazine treatment should be supervised by a consultant psychiatrist

The summary of product characteristics should be consulted before prescribing this drug.


  • (1) Message from Professor Alasdair Breckenridge, Chairman, Committee on Safety of Medicines, Thioridazine: restricted indications and new warnings on cardiotoxicity, 11/12/00.