Abstract
The purpose of this study is to measure the rate of generic drug substitution by pharmacists, and factors influencing generic substitution, such as the extent of drugs listed on the formulary as well as physicians' and patients' acceptance rate of generic substitutes. A total of 9,328 prescription orders were retrospectively reviewed from 94 pharmacies which were selected at random. The substitution rate by pharmacists, which is the rate using the number of prescriptions eligible for substitution as the denominator, has risen from 47% in 1979 to 96% in 1997; double the rate over the past 20 years. The net substitution rate, which uses all prescriptions as the denominator, was 30% in 1997; over 4 times greater than the rate in 1979. Physicians wrote most prescriptions (86%) using the brand name of the drug, which has been the trend for the past 20 years. Of the prescriptions ordered by brand name, 47% were substitutable according to the New Jersey formulary. Of these prescriptions, prescribers allowed generic substitution 77% of the time. Out of these prescriptions, 97% of patients agreed to use a generic substitute if the physician approved of substitution. Generic substitution rates have increased, probably due to greater acceptance of generics by physicians and pharmacists as well as encouragement from external sources such as third party payers. Health care professionals, third parties, and patients all have an important role to play in order to increase the use of generics, and therefore reduce drug expenditures.
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References
Rankin K. Generics: A prognosis on the industry. Drug Store News For The Pharmacist 1996;6(1):13-20.
Solano AP, Pesanello PF. The Impact of Managed Care on the Generic Drug Industry. U.S. Pharmacist November 1997(Supplement: Generic Drug Industry): 4-5.
Rankin K. Where generics fit into the picture. Drug Store News For The Pharmacist 1995;5(8):17-9.
Smith MC. Pharmaceutical Marketing: Strategy and Cases. New York: Haworth Press Inc, 1991:60.
Shah HK. The Next Decade in Generic Pharmaceuticals. Business Quarterly 1985;50(3):95-9.
Anonymous. Setting the Highest Standards. US Pharmacist 1998(Supplement: Generic Drug Industry): 9-10.
Rados B. Generic Drugs: Cutting Cost, Not Corners. FDA Consumer 1985; 19(8):26, 8-9.
Beavers N. Generics' fate in '98: A year of sorting things out. Drug Topics November 1997(Supplement: Generics): 8s-13s.
Mangione RA. Understanding Generic Drug Equivalence. US Pharmacist January 1999; Generic Drug Industry: 51-60.
New Jersey Statutes. Annotated. 1953:45:14-6.
Burton T, Goldberg T, Devito C. A history of anti-substitution laws and their replacement by drug product substitution laws. in: Goldberg T, DeVito C, and Raskin I, Editors. Generic drug laws: A decade of trial-A prescription for progress. Washington DC: National Center for Health Services Research and Technology Assessment, U.S. Department of Health and Human Services, 1986.
Schweitzer SO. Pharmaceutical Economics and Policy. New York: Oxford University Press, 1997: 86.
New Jersey Statutes. Annotated. 1977:24:6E-1 et seq.
The Drug Utilization Review Council. New Jersey Generic Formulary: List of Interchangeable Drug Products. Trenton: New Jersey Department of Health and Senior Services. January 1999.
Culkin TT, Mendell S. 'Generic Substitution' in New Jersey, 1979-87. American Pharmacy 1989; NS29(2): 25-30.
SAS Institute Inc. SAS/STAT User's Guide, Version 6. Cary, NC: SAS Institute, 1989.
Robinson A. After Years of Steady Growth, Winds of Restraint Blowing on Prescription Drug Industry. Canadian Medical Association Journal 1995;153(1):85-8.
Saniell J. Projecting Future Drug Expenditure. Am J Health Syst Pharm 1996;53:139-50.
Bloom BS, Wierz DJ, Pauly MV. Cost and Price of Comparable Branded and Generic Pharmaceuticals. JAMA 1986;256(18): 2523-30.
Carroll NV, Siridhara C, Fincham JE. Factors Affecting Market Acceptance of Generic Drug Products: An Examination of Inherent Risk, Price, and Maximum Allowable Cost Coverage. Akron Business and Economic Review 1987;18(1):11-8.
Carroll NV. Impact of Generic and Therapeutic Interchange Incentives on Community Pharmacy. American Pharmacy 1995;NS35(7):27-34.
Anis AH. Substitution Laws, Insurance Coverage, and Generic Drug Use. Med Care 1994;32(3):240-56.
Banahan BF, Kolassa EM. A Physician Survey on Generic Drugs and Substitution of Critical Dose Medications. Arch Intern Med 1997;157:2080-8.
Shulkin DJ, Giardino AP, Freenock TF, Henriksen DS, Richman C, Friedlander MS, et al. Generic versus brand drug prescribing by resident physicians in Pennsylvania. Am Soc Hosp Pharm 1992;49:625-6.
Southwick K. Branded vs. Generics: Questions on bioequivalence mean state challenges to MCO substitution practices. Managed Healthcare 1997;7(8):33-46.
Stone J. Competitive Incentive Program Analysis And Proposal. American Pharmacy 1986;NS26(7):45-9.
Smith DG. The Effects of Copayments and Generic Substitution on the Use and Cost of Prescription Drugs. Inquiry 1993;30:189-98.
Rheinstein PH. The Generic Drug Approval Process. Am Fam Physician 1993 48(8):1357-60.
Epstien D. Generic Companies at Risk Despite Growing Acceptance. Drug Topics 1997; Generics(Supplement): 26s-7s.
Maline N. What pharmacists really think about brand substitutions. Drug Store News For The Pharmacist 1996;6(8):23-30.
Huttin C. Drug price divergence in Europe: Regulatory aspects. Health Affairs 1999;18(3):245-9.
Kanavos P, Mossialos E. Outstanding regulatory aspects in the European pharmaceutical market. PharmacoEconomics 1999;15(6):519-33.
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Suh, D. Trends of generic substitution in community pharmacies. Pharm World Sci 21, 260–265 (1999). https://doi.org/10.1023/A:1008781619011
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DOI: https://doi.org/10.1023/A:1008781619011