A Retrospective Database Analysis of Prescribing Patterns for Specific Angiotensin Receptor Blockers

Authors and Disclosures

Dr Jan is clinical associate professor of pharmacy practice and administration at the Ernest Mario School of Pharmacy, Rutgers University, Piscataway, NJ, and director of clinical pharmacy services at Horizon Blue Cross Blue Shield of New Jersey in Newark, NJ. Dr Patel is manager of business development in pharmacy services, and Dr Ishak is a clinical pharmacy analyst at Horizon Blue Cross Blue Shield of New Jersey in Newark, NJ. Mr Welz is group project director at Euro RSCG Life Managed Edge in New York City.

Sidebar: Editorial Comment: Off-Label Use Is A Common Though Underexamined Practice

The concept of off-label prescribing, first described to the FDA in 1972, was primarily derived from the 1938 Federal Food, Drug, and Cosmetic Act and its 1962 amendments.^[1] Although the FDA strictly regulates how drugs are advertised and promoted to physicians, these regulations do not preclude a physician's prescribing drugs at dosages different from those indicated or for a condition(s) not described in the package inserts. Often, physicians decide to prescribe a drug for an off-label use or at an unindicated dosage after evaluating available clinical information, such as evidence from peer-reviewed literature and their own observations of patients for whom the drug was prescribed.

Off-label prescribing is a relatively common practice. The American Medical Association estimates that about 50% of all prescriptions in the United States are written for unapproved purposes.^[2] There is no evidence that off-label prescribing results in more frequent adverse outcomes. However, there is a need for more studies of off-label prescribing. Such studies should provide clear descriptions of the methods used to compare drugs or outcomes. In this article, Dr Jan and colleagues provide such an example, explaining how off-label use of angiotensin II receptor blockers (ARBs) is determined and how such practice may increase costs and decrease compliance.

The study findings point to losartan as being the ARB most frequently prescribed for more than once-daily dosing, even though labeling for losartan calls for once-daily initial dosing. In future studies, it may help to differentiate between prescriptions for initial dosing and refill prescriptions. It might be the case, for example, that adjustments in the dosage of losartan are recommended for at least weekly intervals, and patients may undergo a few dosage adjustments during a maximum interval of 7 months.^[3] In addition, some monitoring dosages could have been included as part of the data intended to show only initial dosing. The ramification is that the once-daily dosing parameter needs to be put in context, because inadequate control of hypertension in patients taking losartan can call for dividing the same total daily dose into twice-daily dosing.^[4] This may explain why losartan and eprosartan—the only ARB agents in the study that have been approved for twice-daily dosing and that have proved to produce larger trough responses than once-daily dosing at the same total dose—had the 2 highest percentages for patients dosed more than once a day.^[4,5]

These study results are important but need to be interpreted in light of the limitations in methodology.

Fadia T. Shaya, PhD, MPH,* Jung Kim^†
*Assistant professor and associate director of the Center on Drug and Public Policy, University of Maryland School of Pharmacy, Baltimore
^†PharmD student, University of Maryland School of Pharmacy, Baltimore

References

• Torres A. The use of Food and Drug Administration–approved medications for unlabeled (off-label) uses: the legal and ethical implications. Arch Dermatol. 1994;130:32-36.

• Gorman C. Double-duty drugs: approved medications are being widely prescribed for unapproved uses. Time. September 18, 1995:96.

• Klasco RK, ed. DRUGDEX System. Greenwood Village, Colo: Thomson Micromedex; 2004.

• Cozaar [package insert]. Whitehouse Station, NJ: Merck & Co; 2003.

• Teveten [package insert]. Bridgewater, NJ: Biovail Pharmaceuticals; 2003.