Objectives: The use of opioid analgesics in the United States has significantly increased in recent years. However, there is minimal consensus on what discharge counseling should accompany these high-risk prescriptions and large variations in what is done in practice. The objective of this study was to evaluate the effect of a dual-modality (written and spoken) literacy-appropriate educational strategy on patients' knowledge of and safe use of opioid analgesics.Methods: This was a prospective, randomized controlled trial. Consecutive discharged patients at an urban academic ED (>88,000 visits) with new prescriptions for hydrocodone-acetaminophen were enrolled. Patients were randomized to receive either usual care or the educational intervention. The educational intervention was a one-page information sheet about hydrocodone-acetaminophen, which was both given to the patients and read aloud by the research assistant (nonblinded). Follow-up phone calls were conducted 4 to 7 days after the visit to assess patient knowledge about the medication and self-report of activities associated with safety of use (e.g., double-dipping with acetaminophen, storage, use with alcohol or while driving).Results: A total of 274 patients were enrolled; 210 completed follow-up (110 usual care and 100 intervention). No significant differences in baseline characteristics emerged between the study arms; 42% were male, and 51% were white, with a median age of 43 years. Half of patients had non-back pain orthopedic injuries (49.5%). On follow-up, overall knowledge was poor, with only 28% able to name both active ingredients in the medication. The intervention group had better knowledge of precautions related to taking additional acetaminophen (usual care 18.2%, 95% confidence interval [CI] = 10.9% to 25.5% vs. intervention 38%, 95% CI = 28.3% to 47.7%; difference = 27.6, 95% CI of difference = 21.5 to 33.7) and knowledge of side effects (usual care median = 1, interquartile range [IQR] 0 to 2 vs. intervention median = 2, IQR = 1 to 2; p < 0.0001). Additionally, those who received the intervention were less likely to have reported driving within 6 hours after taking hydrocodone (usual care 13.6%, 95% CI = 7.2% to 20% vs. intervention 3%, 95% CI = -0.3% to 6.3%; difference = 10.6, 95% CI of difference = 3.4 to 17.9). There was no difference between groups related to knowledge about drinking alcohol while taking hydrocodone (overall 18.1%) or knowledge that the opioid could be addictive (overall 72.4%).Conclusions: This simple strategy improved several, but not all, aspects of patient knowledge and resulted in fewer patients in the intervention arm driving while taking hydrocodone. Integration of a patient education document into conversations about opioids holds promise for improving patient knowledge about these high-risk medications.ACADEMIC EMERGENCY MEDICINE 2015;22:331-339