Antipsychotics

All antipsychotics are associated with orthostatic hypotension which can cause dizziness and falls. Their side effects profile includes postural hypotension, anticholinergic effects, akathisia, tardive dyskinesia and sedation. In addition, sedation leading to a slowing of psychomotor function, extrapyramidal gait disturbances, and anticholinergic-related visual blurring could contribute to an increased risk of falls. Phenothiazines may also cause cataracts, and the resultant poor vision could lead to falls.¹

 

Class	Choose	Avoid
First generation2	Higher potency medications from this class are less likely to cause orthostatic hypotension (perphenazine, loxapine, tri- fluoperazine, fluphenazine) and thiothixene)	Low dopamine 2 receptor potency phenothiazine antipsychotics like chlorpromazine and thioridazine are most likely to cause orthostatic hypotension
Second generation2	Lurasidone and Asenapine	Iloperidone which have a higher incidence of orthostatic hypotension

 

Route of administration:²

• Intramuscular administration results in higher elevation of plasma concentration and hence increases risk of side effects. Switch to oral dose if applicable.
• Lowest initial dosage possible and prolonged titration rate to minimise risk of orthostasis.
• If therapy is interrupted for 2 days or more:
  • Re-initiate clozapine at starting dose of 12.5-25mg/day
  • Quetiapine can be initiated at 100mg twice a day
  • Olanzapine can be initiated at 40mg/day in divided doses
  • Risperidone can be initiated at 6mg/day in divided doses

Dosage:²

• Changing the dosing frequency from twice daily to once daily results in higher peak plasma concentration and greater peak trough variability.

Other information:

• Clozapine and quetiapine have the greatest incidence of orthostatic hypotension and hence more likely to cause falls due to the high affinity for alpha1 adrenoreceptor.²
• Consider an agent with the least sedating and anticholinergic effects if appropriate based on the patient’s circumstances. Please refer to AMH table below:³ 

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Overall, there is not enough evidence and studies to completely recommend one drug over the other.