title: Multiple drug intolerance syndrome: prevalence, clinical characteristics, and management.
abstract: BACKGROUND
  Population-based data on the demographics and clinical characteristics of patients with multiple unrelated drug class intolerances noted in their medical records are lacking.
  
  
  OBJECTIVE
  To provide population-based drug "allergy" incidence rates and prevalence, and to identify individuals with multiple drug intolerance syndrome (MDIS) defined by 3 or more unrelated drug class "allergies," and to provide demographic and clinical information on MDIS cases.
  
  
  METHODS
  Electronic medical record data from 2,375,424 Kaiser Permanente Southern California health plan members who had a health care visit and at least 11 months of health care coverage during 2009 were reviewed. Population-based drug "allergy" incidence rates and prevalence were determined for 23 unrelated medication classes.
  
  
  RESULTS
  On January 1, 2009, 478,283 (20.1%) health plan members had at least one reported "allergy." Individuals with a history of at least 1 "allergy" and females, in general, reported higher population-based new "allergy" incidence rates. Multiple drug intolerance syndrome was present in 49,582 (2.1%). The MDIS cases were significantly older, 62.4 ± 16.1 years; heavier, body mass index 29.3 ± 7.1; and likely to be female, 84.9%, compared with average health plan members. They had high rates of health care utilization, medication usage, and new drug "allergy" incidence. They sought medical attention for common nonmorbid conditions.
  
  
  CONCLUSIONS
  Multiple drug intolerance syndrome is in part iatrogenic. It is associated with overweight elderly women who have high rates of health care and medication usage. Urticarial syndromes only explain a small fraction of MDIS cases. Multiple drug intolerance syndrome is associated with anxiety, but not predominately with immunoglobulin E (IgE)-mediated allergy or life-threatening illness. Multiple drug intolerance syndrome can be managed by medication avoidance and judicious rechallenge.
authors.affiliation: Southern California Permanente Medical Group, Department of Allergy, San Diego Medical Center, San Diego, California, USA. eric.m.macy@kp.org
authors.forename: Eric
authors.initials: E
authors.lastname: Macy
authors.forename: Ngoc J
authors.initials: NJ
authors.lastname: Ho
mesh_terms: D000328:Adult; D000367:Age Factors; D000368:Aged; D000806:Angiotensin-Converting Enzyme Inhibitors / Q000009:adverse effects / Q000145:classification; D002140:California / Q000453:epidemiology; D004342:Drug Hypersensitivity / Q000175:diagnosis* / Q000188:drug therapy / Q000453:epidemiology*; D057286:Electronic Health Records; D005260:Female; D006801:Humans; D015994:Incidence; D008297:Male; D008875:Middle Aged; D009294:Narcotics / Q000009:adverse effects / Q000145:classification; D010406:Penicillins / Q000009:adverse effects / Q000145:classification; D017061:Prepaid Health Plans / Q000706:statistics & numerical data*; D015995:Prevalence; D012307:Risk Factors; D012737:Sex Factors; D013577:Syndrome
chemical_list: D000806:Angiotensin-Converting Enzyme Inhibitors; D009294:Narcotics; D010406:Penicillins