Multiple Drug Intolerance Syndrome: A Large-Scale Retrospective Study

BACKGROUND: The term multiple drug intolerance syndrome (MDIS) has been used to describe patients who express adverse drug reactions to three or more drugs without a known immunological mechanism. OBJECTIVE: To identify patient factors that could increase the risk of MDIS. METHOD: Inpatient records over a 5-year period were captured from an electronic prescribing system to identify patients with at least one documented drug allergy. Univariable and multivariable analyses were used to compare the rates of MDIS across age, sex, weight, ethnicity, history of atopy or psychological disorders, and previous admissions. RESULTS: A total of 25,695 patients had a documented drug intolerance, 4.9 % of whom had MDIS. MDIS was significantly more likely in women (p < 0.001), patients with multiple comorbidities (p < 0.001), and patients with previous hospital admissions (p < 0.001). With the exception of penicillin (p = 0.749), MDIS was more frequent in those with allergies to other drugs (p < 0.001). CONCLUSION: MDIS was associated with female gender, multiple comorbidities, and previous hospital admissions. A documented allergy to penicillin did not increase the likelihood of MDIS.