MHRA LogoHome


3. Principal risks and risk-reduction measures

This learning module discusses noteworthy risks for antipsychotics. Summaries of product characteristic1 and the BNF should be consulted for a fuller account of the adverse effects and warnings for individual antipsychotics.

The frequency of adverse effects often varies between different antipsychotics; more information is given in the discussion on individual risks

  • Gastrointestinal adverse effects-including constipation, dry mouth, nausea
  • Central nervous system adverse effects
  • Sedation and sleep disturbances
  • Extrapyramidal side effects-acute dystonia, akathisia, parkinsonism, tardive dyskinesia
  • Neuroleptic malignant syndrome
  • Convulsions
  • Cardiovascular adverse effects
  • Blood pressure changes
  • Cerebrovascular events
  • Cardiac rhythm disorders particularly QT interval prolongation
  • Venous thromboembolism
  • Metabolic adverse effects-including weight gain, dyslipidaemia, hyperglycaemia
  • Hyperprolactinaemia and sexual adverse effects-including menstrual disturbances, sexual dysfunction, osteoporosis
  • Blood disorders-including neutropenia, agranulocytosis
  • Temperature regulation-hypothermia and hyperthermia
  • Adverse effects on the skin-including rash, pruritus, photosensitivity
  • Adverse effects on the eye-including precipitation of glaucoma, mydriasis, and pigmentation
  • Antimuscarinic2 adverse effects-including constipation, nasal stuffiness, and urinary retention
  • Dependence and withdrawal reactions
  • Drug interactions-including interactions which increase adverse effects (hypotension, sedation, cardiac rhythm disturbances)

Precautions and risks associated with special uses of antipsychotics

  • Use in elderly patients with dementia-increased risk of stroke and higher mortality rate
  • Pregnancy and breastfeeding-need for careful weighing up of benefit and risk for mother and baby
  • Prolonged-release antipsychotic injections-need for care to initiate treatment and for correct administration technique
  • Antipsychotic injections for immediate effect-need for careful evaluation of circumstances for use, use of appropriate dose, close monitoring of patient
  • Clozapine-special risks include agranulocytosis, myocarditis, cardiomyopathy, intestinal obstruction, hypersalivation

  1. Summary of product characteristics, a document that forms the basis of information for European Union health professionals on how to use a medicinal product safely and effectively; it reflects the data assessed for granting marketing authorisation
  2. Reduction or blocking of the effects of parasympathetic nerves; antimuscarinic effects include dry mouth, difficulty swallowing, blurred vision, confusion, palpitations, constipation, and urine retention