Elderly patients with dementia should avoid taking certain antipsychotic medications because of an increased risk of death, says a warning issued by Health Canada. 

Recent studies of the drugs, known as second-generation, or atypical, antipsychotics, show that elderly patients with dementia prescribed the medications had a death rate 1.6 times higher than that of patients taking a placebo, or dummy pill. 

The studies examined risperidone (Risperdal), quetiapine (Seroquel) and olanzapine (Zyprexa). There were no studies on clozapine (Clozaril) in older patients with dementia, but because Clozaril is from the same family of drugs, it is included in Wednesday's advisory. 

Seroquel, Zyprexa and Clozaril are not approved for treating behavioural disorders in elderly patients with dementia. 

These three drugs, along with Risperdal, are approved for treating schizophrenia. Risperdal is also approved for the short-term treatment of aggression and/or psychosis in patients with severe dementia. 

Health Canada is requesting that all manufacturers of these drugs include a warning and description of the risk in the safety information sheet for each drug. 

Patients should not stop taking the medication without first consulting their physician, as discontinuing any prescribed drug could pose a risk to health.