Medicine By Numbers: 131 Million

October 28, 2011

By Maryann Kwa, MD

Faculty Peer Reviewed

131 million: The number of times the most popular medication in the United States was prescribed in 2010.

Recently, IMS Health, a company that monitors annual sales for pharmaceutical and healthcare industries, published a list of the most prescribed medications in the United States in 2010 [1].

Medication Number of Prescriptions in 2010(in millions)
1. Hydrocodone/Acetaminophen 131.2
2. Simvastatin 94.1
3. Lisinopril 87.4
4. Levothyroxine sodium 70.5
5. Amlodipine 57.2
6. Omeprazole 53.4
7. Azithromycin 52.6
8. Amoxicillin 52.3
9. Metformin 48.3
10. Hydrochlorothiazide 47.8
11. Alprazolam 46.3
12. Lipitor 45.3
13. Furosemide 43.4
14. Metoprolol tartrate 38.9
15. Zolpidem tartrate 38.0
16. Atenolol 36.3

Number one on that list is Vicodin, a narcotic painkiller that combines hydrocodone with acetaminophen.  Annually, it was prescribed 131.2 million times (brand and generic) in the inpatient and outpatient setting.  Interestingly, the FDA advisory panel recently recommended banning both Vidocin and Percocet [2].  The high doses of acetaminophen can cause liver failure, and patients taking these medications for extended durations require higher doses to achieve the same effect.  In the US, approximately 42,000 people are hospitalized and more then 400 die every year from acetaminophen toxicity from misuse of Vicodin and similar drugs.  Currently, the FDA recommends limiting the amount of acetaminophen in prescription opioids to 325 milligrams per pill [3].

The other medications on the list are dominated not by the latest brand names but by older drugs that are now generic.  Only one medication, Pfizer’s Lipitor (atorvastatin), is a big-selling brand name.  Generic versions of Vicodin cost around 30 cents per pill compared with four dollars for Lipitor.  Lipitor still makes more in annual sales ($7.5 billion) than any other medication but only ranks twelfth in popularity with 45.3 million prescriptions.  It will be interesting to see what happens to these numbers when generic Atorvastatin reaches the market in November 2011.

According to IMS Health, total prescription sales in the US grew 2.3% percent in 2010, reaching $307 billion, continuing the trend of 5% or lower growth annually that has occurred since 2007 [1].  In addition, the use of generics (including branded generics) continued to rise last year and now represents 75 percent of all prescriptions (up from 57 percent in 2004).  It appears that the greater availability of generic medications, the growing differential in co-pays between brand names and generics, and efforts by physicians and pharmacists to encourage the use of lower-cost alternatives are key factors influencing the number of generic prescriptions written.

Not surprisingly, six of the top 16 most prescribed medications are used to treat hypertension (see table).  Upon closer scrutiny, however, the ranking of the medications is interesting in several aspects.  For example, an ACE inhibitor (lisinopril) was the most prescribed, followed by a calcium channel blocker (amlodipine), and then a thiazide diuretic (hydrochlorothiazide).  Given that hydrochlorothiazide is usually the first line medication for hypertension, it is reasonable to expect that it would have placed higher on the list.  In addition, if the two beta blockers (metoprolol and atenolol) were to be combined into a single class, the number of prescriptions would almost equal that of lisinopril.  So in theory, the total number of beta blockers prescribed was greater than what appears on the list.

Another surprise (or not) is the seventh and eighth most popular drugs, azithromycin and amoxicillin.  For medications that should only be used intermittently and not on a daily basis, the number of prescriptions is staggering.  There is good evidence from a May 2010 systematic review article with meta-analysis in the British Medical Journal which showed the development of antimicrobial resistance in patients prescribed antibiotics by primary care physicians—mostly for respiratory or urinary tract infections [4].  These results may be attributed to physicians prescribing antibiotics for a high proportion of infections even if the etiology is likely viral.  By doing this, some providers may think they’re helping patients by at least covering the possibility of a missed diagnosis of bacterial disease.  However, physicians are not all to blame.  Another barrier is the public attitude toward antibiotics.  Patients often expect an antibiotic for any type of infection and have the impression that antibiotics work on viruses.  Educating patients about the proper use of antibiotics and growing antibiotic resistance is therefore an important discussion between provider and patient.

Overall, the list from IMS Health reveals interesting and important details about the current prescribing habits of physicians.  Brand name medicine manufacturers are gradually losing their hold on the average customer as cheaper generics become the status quo.  Also, the increasing prevalence of antimicrobial resistance from indiscriminate or poor utilization of antibiotics requires thoughtful intervention.

Dr. Maryann Kwa is a 3rd year resident at NYU Langone Medical Center

Peer reviewed by Neil Shapiro, MD, Editor-In-Chief, Clinical Correlations

References:

[1] IMS Institute for Healthcare Informatics. The use of medicines in the United States: review of 2010. IMS Health.com; 2011 July 1. Available from: http://www.imshealth.com/deployedfiles/imshealth/Global/Content/IMS%20Institute/Static%20File/IHII_UseOfMed_report.pdf

[2] Harris G. Ban is advised on 2 top pills for pain relief. The New York Times; 2009 July 1. Available from: http://www.nytimes.com/2009/07/01/health/01fda.html

[3] Heavey S. FDA seeks less acetaminophen in prescription drugs. Reuters; 2011 January 13. Available from: http://www.reuters.com/article/idUSTRE70C48O20110113

[4] Costelloe C., et al. Effect of antibiotic prescribing in primary care on antimicrobial resistance in individual patients: systematic review and meta-analysis. British Medical Journal. 2010;340:c2096. Available from: http://www.bmj.com/content/340/bmj.c2096.full

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