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Opioid analgesics, while important for the treatment of pain, are associated with high rates of abuse. Most abusers report they obtained prescriptions on their own or medications from friends and relatives who had been prescribed opioids. We analyzed prescription practices in the United States to identify possible contributors to the high rate of opioid analgesic abuse. We paid particular attention to prescription practices in youth, for whom prescriptions of controlled medications, including opioids, have nearly doubled between 1994 and 2007.1
The data were acquired through the Vector One: National (VONA) database from SDI Health (Plymouth Meeting, Pennsylvania). SDI receives prescription data from 35 015 of the 62 132 retail pharmacies in the United States. These pharmacies dispense nearly half of all retail prescriptions nationwide. Detailed information about SDI's coverage statistics is proprietary. SDI receives 1.4 billion prescription claims per year representing 121 million unique patients. The sample is nationally representative. More detailed information about VONA can be obtained elsewhere.2 We analyzed opioid prescriptions in 2009 as a function of physician specialty (using SDI descriptors), patient age, duration of prescription, and whether the patient had filled a prior prescription (from the same or a different provider) for an opioid analgesic within the past month. We compared differences between prescriptions by age groups and by medical specialty using 2-sample t tests (SAS version 9.1; SAS Institute, Cary, North Carolina). To avoid a potential type I error when making multiple comparisons, we applied a Bonferroni correction and a more conservative significance level of P<.001. This research was exempt from 45 CFR part 46 requirements under 45 CFR 46.101(b)(4).
There were 79.5 million prescriptions for opioid analgesics captured (39% of the estimated projection of 201.9 million opioid prescriptions dispensed in the US in 2009). Most prescriptions were for hydrocodone- and oxycodone-containing products (84.9%, 67.5 million) and issued for short treatment courses (19.1% for <2 weeks, 65.4% for 2-3 weeks). The percentage of prescriptions dispensed increased with age, from 0.7% in those aged 0 to 9 years to 28.3% in those 60 years and older. Of all opioid prescriptions, 11.7% (9.3 million) were for patients between 10 and 29 years old, while 45.7% (36.4 million) were for those between 40 and 59 years old. Overall, the main prescribers were primary care physicians (general practitioner/family medicine/osteopathic physicians) with 28.8% (22.9 million) of total prescriptions, followed by internists (14.6%, 11.6 million), dentists (8.0%, 6.4 million), and orthopedic surgeons (7.7%, 6.1 million). For patients aged 10 to 19 years, dentists were the main prescribers (30.8%, 0.7 million), followed by primary care (13.1%, 0.3 million) and emergency medicine physicians (12.3%, 0.3 million) (Figure 1). All comparisons between specialties within an age group were significantly different from each other (P<.001), except general practitioners and emergency medicine physicians in the 0- to 9-year-old group (P=.34) and dentists and internists in the 30- to 39-year-old group (P=.06). For patients 40 years and older, primary care physicians were the main prescribers (30.4%, 17.9 million). On average, across all physician specialties included in this analysis, 56.4% (44.8 million) of opioid prescriptions were dispensed to patients who had already filled another opioid prescription within the past month (Figure 2).
Our analysis identified questions for further investigation. For example, do the 11.7% of prescriptions issued to those aged 10 to 29 years signal a potential problem for this population, which is the most likely to abuse drugs and develop addiction?3,4 Another unknown is whether the percentage of opioid prescriptions (56%) that were filled by patients who had recently received another opioid prescription is justified or suggests the need to improve information infrastructures that could enhance the safety of prescribed opioid analgesics and minimize diversion. Our conclusions are limited because causal links with opioid diversion and abuse cannot be drawn from prescribing practices alone and our analysis cannot account for illegal prescriptions. Nonetheless, the recent increases in opioid prescriptions5 and associated increases in abuse and overdoses6 highlight the need for additional research to understand positive and negative effects of current prescribing practices.
We kindly acknowledge Ruben Baler, PhD, National Institute on Drug Abuse, for his editorial assistance and critical comments. He did not receive compensation for his contribution besides his salary. This research was carried out at the National Institute on Drug Abuse, National Institutes of Health (NIH).
Author Contributions: Ms Cotto had full access to all of the data in the study and takes responsibility for the integrity of the data and the accuracy of the data analysis.
Study concept and design: Volkow, McLellan, Weiss.
Acquisition of data: Cotto, Karithanom, Weiss.
Analysis and interpretation of data: Volkow, McLellan, Cotto, Karithanom, Weiss.
Drafting of the manuscript: Volkow, McLellan, Cotto, Karithanom, Weiss.
Critical revision of the manuscript for important intellectual content: McLellan, Weiss.
Statistical analysis: Cotto, Karithanom.
Study supervision: Volkow, Weiss.
Conflict of Interest Disclosures: All authors have completed and submitted the ICMJE Form for Disclosure of Potential Conflicts of Interest and none were reported.
Nora D. Volkow, National Institute on Drug Abuse National Institutes of Health Bethesda, Maryland ; Email: vog.hin.adin@woklovn..
Thomas A. McLellan, Center for Substance Abuse Solutions University of Pennsylvania School of Medicine Philadelphia.