title: Patient misunderstanding of dosing instructions.
abstract: OBJECTIVE
  To compare outpatients' understanding of medication dosing instructions written in terms of daily frequency with patients' understanding of instructions specifying hourly intervals.
  
  
  METHODS
  Prospective cohort study involving patient interviews.
  
  
  METHODS
  A university hospital outpatient pharmacy.
  
  
  METHODS
  Five hundred patients presenting new and refill prescriptions to the hospital outpatient pharmacy.
  
  
  METHODS
  Patients were interviewed using a standardised questionnaire.
  
  
  RESULTS
  Of the 71 patients with prescriptions specifying dosing instructions in hourly intervals (e.g., q6h), 55 (77%) misinterpreted the recommended frequency of dosage compared with only 4 (0.99%) of the 429 patients with dosing instructions specifying daily frequency (e.g., qid) (relative risk 83; 95% confidence interval 31-200). This difference remained when patient subgroups were evaluated by education level, new versus refill prescriptions, and analgesic versus nonanalgesic medications.
  
  
  CONCLUSIONS
  This study indicates that the intended dosing regimen is frequently misunderstood when the physician writes outpatient prescriptions in hourly intervals. To promote optimal patient compliance, the outpatient prescription label should state the number of times a day a medication is to be taken.
authors.affiliation: Hospital of the University of Pennsylvania, Philadelphia, USA.
authors.forename: N A
authors.initials: NA
authors.lastname: Hanchak
authors.forename: M B
authors.initials: MB
authors.lastname: Patel
authors.forename: J A
authors.initials: JA
authors.lastname: Berlin
authors.forename: B L
authors.initials: BL
authors.lastname: Strom
mesh_terms: D000328:Adult; D015331:Cohort Studies; D004334:Drug Administration Schedule; D004348:Drug Labeling; D011307:Drug Prescriptions; D004358:Drug Therapy; D005260:Female; D006801:Humans; D008297:Male; D010045:Outpatients / Q000523:psychology; D010349:Patient Compliance; D011446:Prospective Studies; D011795:Surveys and Questionnaires