Atypical antipsychotic. Dopamine-receptor and 5HT2A- receptor antagonist. Compared with typical antipsychotics (e.g. haloperidol) the incidence of drug-induced movement disorders is less

Onset of action: hours to days
Duration of action: 12-48 h (sometimes longer)
Plasma ½ life: 24 h


  • Starting: 0.5 mg bid and prn PO
  • Increase by 0.5 mg bid PO every other day


  • Headache
  • Agitation
  • Anxiety
  • Insomnia
  • Movement disorders
  • Sedation
  • Fatigue
  • Dizziness
  • Impaired concentration
  • Blurred vision
  • Dyspepsia
  • Nausea and vomiting
  • Constipation
  • Urinary incontinence
  • Rhinitis


  • Increased risk of cerebrovascular adverse events and death in elderly patients with dementia
  • May cause orthostatic hypotension
  • Should not be used in Parkinson’s disease
  • Watch for extrapyramidal effects (EPS). If present decrease or discontinue and treat EPS symptoms using anticholinergics (benztropine), beta-blockers or benzodiazepines if necessary
  • Drug interactions exist


This information is drawn from a number of sources (see below). The reader is encouraged to access these and other relevant literature for more detail. As always, sound clinical judgment should be used in individual clinical cases. In particular, it should be remembered that there may be significant variation in the pharmokinetics of a drug resulting from a number of factors, including the individual patient’s metabolism/disease status and how the medication has been formulated.


  1. Brunton LL, Lazo JS, Parker KL, editors. Goodman and Gilman’s: the pharmacological basis of therapeutics. 11th ed. McGraw-Hill Professional; 2006.
  2. Twycross R, Wilcock A. Palliative care formulary. 3rd ed. Radcliffe Medical Press Ltd; 2008.
  3. Repchinsky C, editor. Compendium of pharmaceuticals and specialties (CPS): the Canadian drug reference for health professionals. 44th ed. Canadian Pharmacists Association; 2009.
  4. Goldman A, Hain R, Liben S. Oxford textbook of palliative care for children. 1st ed. Oxford University Press; 2006.

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