Atypical Antipsychotics

The newer “atypical antipsychotic” drugs are better tolerated than the older (standard) antipsychotics with less extra-pyramidal side-effects.

• First line treatment of newly diagnosed schizophrenia.¹
• Acute treatment of an acute schizophrenic episode.
• Treatment of patients on conventional antipsychotics where treatment is ineffective or causing unacceptable side-effects.
• Risperidone is indicated for the short-term treatment of severe aggression and violence (whether directed towards self or others) in autistic children where available non-pharmacological methods have first been tried and failed.²

• First line drugs in this group are amisulpride, olanzapine, quetiapine, risperidone, and zotepine.³
• Risperidone or olanzapine should not be used in patients with known or suspected cerebrovascular disease:⁴
  • CSM has advised that risperidone or olanzapine should not be used for the treatment of behavioural symptoms of dementia.^{5 6}
  • Use of risperidone for the management of acute psychotic conditions in elderly patients who also have dementia should be limited to short-term and should be under specialist advice (olanzapine is not licensed for management of acute psychoses).
  • Prescribers should consider carefully the risk of cerebrovascular events before treating any patient with a previous history of stroke or transient ischaemic attack. Consideration should also be given to other risk factors for cerebrovascular disease including hypertension, diabetes, current smoking and atrial fibrillation.
• Some drugs increase prolactin - if fertility is required switching to aripiprazole, clozapine, olanzapine, quetiapine, or sertindole which have no significant effect on prolactin concentration.³
• Clozapine should only be used second line for schizophrenia in patients who have failed to respond or intolerant of other drugs, i.e after the sequential use (each >6-8 weeks) of ≥2 antipsychotics (one of which should be an atypical antipsychotic).³
• Sertindole is also restricted to patients who are enrolled in clinical studies and who are intolerant of other drugs, because of worries about possible arrhythmias.³

• Co-prescribing with other drugs that increase the QT interval
• Cardiovascular disease
• History of epilepsy
• Elderly - particularly in patients with dementia⁷ or those with increased risk of stroke.

• Warn patients that atypical antipsychotics may affect their ability to drive performance.
• Weight gain may occur.
• Dizziness and postural hypotension ±reflex tachycardia may occur, particularly on initial dose titration.
• Mild extrapyramidal symptoms, e.g. drug-induced parkinsonism (reduce dose or add antimuscarinic drug). Occasionally tardive dyskinesia (involuntary movements, usually of tongue, face, and jaw) may occur after long-term administration - stop drug if early signs appear as this may not be reversible.
• Hyperglycaemia ±diabetes can occur, particularly with clozapine and olanzapine.
• Neuroleptic malignant syndrome is a rare side effect.

• Initiate at low dose and titrate dose up gradually (to avoid side effects e.g. postural hypotension)
• Monitor weight and plasma glucose regularly (i.e. screen for any diabetes)

Withdrawal should be gradual and closely monitored to avoid relapse or acute withdrawal syndromes.