title: Association between oral fluoroquinolones and seizures: A self-controlled case series study.
abstract: OBJECTIVE
  The aim of this study was to investigate the association and to estimate the crude absolute risk of seizure among patients exposed to fluoroquinolones (FQs) in Hong Kong and the United Kingdom.
  
  
  METHODS
  A self-controlled case series study was conducted. Data were collected from the Hong Kong Clinical Data Analysis and Reporting System database and the Clinical Practice Research Datalink. Patients who were prescribed any oral FQ and had an incident seizure diagnosis from 2001 to 2013 were included. The risk windows were defined as pre-FQ start, FQ-exposed, and post-FQ completion. Incidence rate ratios were estimated in all risk windows and compared with baseline periods. A post hoc subgroup analysis was conducted to examine the effect of patients with a history of seizure.
  
  
  RESULTS
  An increased incidence rate ratio was found in the pre-FQ start periods and no association was found in the post-FQ completion periods in both databases. The crude absolute risk of an incident seizure in 10,000 oral FQ prescriptions was 0.72 (95% confidence interval 0.47-1.10) in the Clinical Data Analysis and Reporting System and 0.40 (95% confidence interval 0.30-0.54) in the Clinical Practice Research Datalink. The rate ratio during treatment was not higher than pre-FQ start periods among patients with a history of seizure, therefore the results did not raise serious concerns.
  
  
  CONCLUSIONS
  This study does not support a causal association between the use of oral FQs and the subsequent occurrence of seizure. An increased risk before the FQ exposure period suggests that the clinical indication for which FQ was prescribed may have contributed to the development of seizure rather than the drug itself.
authors.affiliation: From the Centre for Safe Medication Practice and Research (C.S.L.C., E.W.C., A.Y.S.W., I.C.K.W.), Department of Pharmacology and Pharmacy, Li Ka Shing Faculty of Medicine, The University of Hong Kong, PR China; Department of Non-communicable Disease Epidemiology (A.R., I.J.D.), Faculty of Epidemiology and Population Health, London School of Hygiene and Tropical Medicine; Research Department of Practice and Policy (I.C.K.W.), UCL School of Pharmacy, London, UK.
authors.forename: Celine S L
authors.initials: CS
authors.lastname: Chui
authors.affiliation: From the Centre for Safe Medication Practice and Research (C.S.L.C., E.W.C., A.Y.S.W., I.C.K.W.), Department of Pharmacology and Pharmacy, Li Ka Shing Faculty of Medicine, The University of Hong Kong, PR China; Department of Non-communicable Disease Epidemiology (A.R., I.J.D.), Faculty of Epidemiology and Population Health, London School of Hygiene and Tropical Medicine; Research Department of Practice and Policy (I.C.K.W.), UCL School of Pharmacy, London, UK.
authors.forename: Esther W
authors.initials: EW
authors.lastname: Chan
authors.affiliation: From the Centre for Safe Medication Practice and Research (C.S.L.C., E.W.C., A.Y.S.W., I.C.K.W.), Department of Pharmacology and Pharmacy, Li Ka Shing Faculty of Medicine, The University of Hong Kong, PR China; Department of Non-communicable Disease Epidemiology (A.R., I.J.D.), Faculty of Epidemiology and Population Health, London School of Hygiene and Tropical Medicine; Research Department of Practice and Policy (I.C.K.W.), UCL School of Pharmacy, London, UK.
authors.forename: Angel Y S
authors.initials: AY
authors.lastname: Wong
authors.affiliation: From the Centre for Safe Medication Practice and Research (C.S.L.C., E.W.C., A.Y.S.W., I.C.K.W.), Department of Pharmacology and Pharmacy, Li Ka Shing Faculty of Medicine, The University of Hong Kong, PR China; Department of Non-communicable Disease Epidemiology (A.R., I.J.D.), Faculty of Epidemiology and Population Health, London School of Hygiene and Tropical Medicine; Research Department of Practice and Policy (I.C.K.W.), UCL School of Pharmacy, London, UK.
authors.forename: Adrian
authors.initials: A
authors.lastname: Root
authors.affiliation: From the Centre for Safe Medication Practice and Research (C.S.L.C., E.W.C., A.Y.S.W., I.C.K.W.), Department of Pharmacology and Pharmacy, Li Ka Shing Faculty of Medicine, The University of Hong Kong, PR China; Department of Non-communicable Disease Epidemiology (A.R., I.J.D.), Faculty of Epidemiology and Population Health, London School of Hygiene and Tropical Medicine; Research Department of Practice and Policy (I.C.K.W.), UCL School of Pharmacy, London, UK.
authors.forename: Ian J
authors.initials: IJ
authors.lastname: Douglas
authors.affiliation: From the Centre for Safe Medication Practice and Research (C.S.L.C., E.W.C., A.Y.S.W., I.C.K.W.), Department of Pharmacology and Pharmacy, Li Ka Shing Faculty of Medicine, The University of Hong Kong, PR China; Department of Non-communicable Disease Epidemiology (A.R., I.J.D.), Faculty of Epidemiology and Population Health, London School of Hygiene and Tropical Medicine; Research Department of Practice and Policy (I.C.K.W.), UCL School of Pharmacy, London, UK. i.wong@ucl.ac.uk.
authors.forename: Ian C K
authors.initials: IC
authors.lastname: Wong
mesh_terms: D000284:Administration, Oral; D000368:Aged; D000900:Anti-Bacterial Agents / Q000008:administration & dosage* / Q000009:adverse effects*; D005260:Female; D024841:Fluoroquinolones / Q000008:administration & dosage* / Q000009:adverse effects*; D005500:Follow-Up Studies; D006723:Hong Kong / Q000453:epidemiology; D006801:Humans; D015994:Incidence; D008297:Male; D008875:Middle Aged; D012306:Risk; D012640:Seizures / Q000453:epidemiology*; D012680:Sensitivity and Specificity; D006113:United Kingdom / Q000453:epidemiology
chemical_list: D000900:Anti-Bacterial Agents; D024841:Fluoroquinolones