Allergy to Antipsychotics Often a False Diagnosis
Marlene Busko
October 10, 2008 (Chicago, Illinois) ? New research shows that fewer than 10% of patients with pharmacy records listing an allergy to antipsychotics actually had a true allergy, a finding that suggests drug-treatment options might be needlessly limited by this false assessment.
Jeffrey R. Nurenberg, MD, and Stephen J. Schleifer, MD, from Greystone Park Psychiatric Hospital, in Morris Plains, New Jersey, found that of 79 patients listed in pharmacy records as having an allergy to an antipsychotic agent, only 7 had any evidence to support a true allergy. Further, they found it was possible, but unlikely, that 12 other patients had an allergy to these agents.
The findings were presented here at the American Psychiatric Association 60th Institute on Psychiatric Services.
"A genuine antigen-antibody response to a medicine can create a serious life-threatening problem. Unfortunately, an extraordinarily high number of people have a past history of 'allergy' that turns out to be unwarranted, and this may increase their likelihood of receiving treatment with less effective or more costly medications," he said.
Surprisingly High Rate of "Allergies"
A review of pharmacy records at a New Jersey state psychiatric hospital revealed a surprisingly high rate of allergy to antipsychotics and other psychotropic agents. This led to the current investigation to determine whether this observation was valid.
Investigators randomly selected patient records from a single day in January 2006. On that date, 301 of 585 inpatients (51.5%) were listed as having at least 1 allergy to a medication.
Of the 585 patients, 138 patients (23.6%) were listed as having allergies to 1 or more antipsychotic agents, including haloperidol (11.1%), chlorpromazine (6.0%), fluphenazine (4.8%), and risperidone (4.1%).
Of the patients listed as allergic to antipsychotics, 51 were no longer in the hospital and 8 refused or were unable to participate in the study.
The investigators reviewed the clinical chart summaries and interviewed the 79 remaining patients to look for evidence of a true allergy or evidence of a nonallergic adverse drug reaction that might have been incorrectly diagnosed as an allergy.
True allergies among the 79 patients were much lower than the reported rates. A total of 7 (8.9%) patients had evidence of a true allergic reaction to an antipsychotic, 12 (15.2%) had weak evidence for a possible but unlikely allergic reaction, and 60 (75.9%) had no evidence of an allergic reaction.
The 7 patients with true allergies to antipsychotics were 1 patient with schizophrenia and 6 patients with schizoaffective disorder. They were allergic to haloperidol (3 patients), chlorpromazine (3 patients), clozapine (2 patients), risperidone (1 patient), and quetiapine (1 patient).
False Allergy Label Limits Treatment Options
The data support the hypothesis that true allergy to antipsychotics is much lower than reported rates reflected in clinical and pharmacy records, the authors conclude.
A true allergy to a medication can lead to a serious, potentially life-threatening condition, but many patients mistakenly think that any adverse reaction to a drug is an allergy, said Dr. Nurenberg. This then becomes part of their medical record and follows them whenever they are referred to a new healthcare provider.
Patients might be prescribed a newer agent with a risk for metabolic adverse effects when another agent that they were not truly allergic to might have been safe and effective.
It is important to take a careful clinical history about reported allergies to get an accurate assessment of medications that are safe and most likely to be effective in an individual patient, he said.
The study was funded by the State of New Jersey Department of Human Services. Dr. Nurenberg has disclosed no relevant financial relationships.
American Psychiatric Association 60th Institute on Psychiatric Services: Poster 37. Presented October 2, 2008.
Marlene Busko
October 10, 2008 (Chicago, Illinois) ? New research shows that fewer than 10% of patients with pharmacy records listing an allergy to antipsychotics actually had a true allergy, a finding that suggests drug-treatment options might be needlessly limited by this false assessment.
Jeffrey R. Nurenberg, MD, and Stephen J. Schleifer, MD, from Greystone Park Psychiatric Hospital, in Morris Plains, New Jersey, found that of 79 patients listed in pharmacy records as having an allergy to an antipsychotic agent, only 7 had any evidence to support a true allergy. Further, they found it was possible, but unlikely, that 12 other patients had an allergy to these agents.
The findings were presented here at the American Psychiatric Association 60th Institute on Psychiatric Services.
"A genuine antigen-antibody response to a medicine can create a serious life-threatening problem. Unfortunately, an extraordinarily high number of people have a past history of 'allergy' that turns out to be unwarranted, and this may increase their likelihood of receiving treatment with less effective or more costly medications," he said.
Surprisingly High Rate of "Allergies"
A review of pharmacy records at a New Jersey state psychiatric hospital revealed a surprisingly high rate of allergy to antipsychotics and other psychotropic agents. This led to the current investigation to determine whether this observation was valid.
Investigators randomly selected patient records from a single day in January 2006. On that date, 301 of 585 inpatients (51.5%) were listed as having at least 1 allergy to a medication.
Of the 585 patients, 138 patients (23.6%) were listed as having allergies to 1 or more antipsychotic agents, including haloperidol (11.1%), chlorpromazine (6.0%), fluphenazine (4.8%), and risperidone (4.1%).
Of the patients listed as allergic to antipsychotics, 51 were no longer in the hospital and 8 refused or were unable to participate in the study.
The investigators reviewed the clinical chart summaries and interviewed the 79 remaining patients to look for evidence of a true allergy or evidence of a nonallergic adverse drug reaction that might have been incorrectly diagnosed as an allergy.
True allergies among the 79 patients were much lower than the reported rates. A total of 7 (8.9%) patients had evidence of a true allergic reaction to an antipsychotic, 12 (15.2%) had weak evidence for a possible but unlikely allergic reaction, and 60 (75.9%) had no evidence of an allergic reaction.
The 7 patients with true allergies to antipsychotics were 1 patient with schizophrenia and 6 patients with schizoaffective disorder. They were allergic to haloperidol (3 patients), chlorpromazine (3 patients), clozapine (2 patients), risperidone (1 patient), and quetiapine (1 patient).
False Allergy Label Limits Treatment Options
The data support the hypothesis that true allergy to antipsychotics is much lower than reported rates reflected in clinical and pharmacy records, the authors conclude.
A true allergy to a medication can lead to a serious, potentially life-threatening condition, but many patients mistakenly think that any adverse reaction to a drug is an allergy, said Dr. Nurenberg. This then becomes part of their medical record and follows them whenever they are referred to a new healthcare provider.
Patients might be prescribed a newer agent with a risk for metabolic adverse effects when another agent that they were not truly allergic to might have been safe and effective.
It is important to take a careful clinical history about reported allergies to get an accurate assessment of medications that are safe and most likely to be effective in an individual patient, he said.
The study was funded by the State of New Jersey Department of Human Services. Dr. Nurenberg has disclosed no relevant financial relationships.
American Psychiatric Association 60th Institute on Psychiatric Services: Poster 37. Presented October 2, 2008.
