Trends in outpatient prescription drug use and related costs in the US: 1998-2003.

OBJECTIVE: To present a brief synopsis of trends in the number of prescriptions and retail costs of outpatient drugs dispensed in the US between 1998 and 2003. METHODS: Data were extracted from IMS Health, the National Prescription Audit Plus and the National Disease and Therapeutic Index databases. RESULTS: In 1998, 2.7 billion outpatient prescriptions were dispensed versus 3.6 billion in 2003. This equates to a 33.3% increase over the 6-year period. Of the top 20 most dispensed drugs by volume, 40% were launched in the 1990s or 2000s. Retail costs for the total market of dispensed outpatient prescription drugs were 96.1 billion US dollars in 1998 and 196 billion US dollars in 2003, a 104% increase. Of the top 20 most dispensed drugs by retail cost, all were tradename drugs and were launched in the 1990s or 2000s. CONCLUSIONS: These data indicate a large increase in the US over a short time period in dispensed outpatient prescriptions and their associated retail costs.

Detection of systemic hypersensitivity to drugs using standard guinea pig assays.

The most commonly used assays designed to detect either skin or systemic immune-based hypersensitivity reactions are those using guinea pigs (GP). We obtained data from various FDA records to evaluate the correlation between GP assay results and reported post-marketing systemic hypersensitivity reactions. We examined the new drug application (NDA) reviews of approved drugs for the results of GP assays. Post-marketing human data were extracted from the FDA adverse event reporting system (AERS). Drug usage data were obtained from a commercial database maintained by IMS Health Inc. We found 83 (21%) of 396 drugs approved between 1978 and 1998 had reported GP test results. Among these 83 drugs, 14 (17%) were found to have positive results in at least one GP assay. Simple reporting index (RI) values for systemic hypersensitivity reactions were calculated from AERS data and usage to produce the index of adverse event reports per million shipping units of drug. A variety of definitions of positive human response were examined. A statistically significant association was seen for rash between post-marketing and clinical trials adverse event reports. No statistically significant associations between human data and GP test results were observed. These data suggest that standard GP assays have limited ability to predict human systemic hypersensitivity potential for pharmaceuticals.

Use of medications for erectile dysfunction in the United States, 1996 through 2001.

PURPOSE: We describe the use during 1996 through 2001 of the primary medications approved in the United States for treatment of erectile dysfunction, namely alprostadil injection and urethral suppository, and sildenafil. MATERIALS AND METHODS Two pharmaceutical research data bases, the National Prescription Audit Plus, and National Disease and Therapeutic Index, were accessed and analyzed. Ancillary data were obtained from 2 health plans. RESULTS: Increases in the number of dispensed prescriptions for alprostadil injection and urethral suppository marketed in 1995 and 1996, respectively, were reversed in 1998 by the marketing of sildenafil. From 1998 through 2001 the estimated number of prescriptions for sildenafil increased 1.87-fold or 87% from 7.5 million to 14 million, while those for alprostadil injection decreased 33% from 239,000 to 159,000 and those for alprostadil suppository decreased 67% from 400,000 to 132,000. Sildenafil was prescribed proportionately more frequently for younger men than alprostadil injection or suppository (p <0.0001). Compared with men for whom sildenafil was prescribed in 1998 those prescribed the drug in 2001 were younger (p <0.0001). Alprostadil injection and suppository were prescribed proportionately more frequently by urologists than sildenafil. Ancillary data from 2 health plans indicated a 173% increase in 1 plan and a 25% decrease in the other due to restrictions in sildenafil prescriptions from 1998 through 2001. CONCLUSIONS: Due to the marketing of sildenafil in 1998 through 2001 the use of 2 approved medications for erectile dysfunction, namely alprostadil injection and alprostadil urethral suppository, decreased, while the use of sildenafil increased. Sildenafil was prescribed proportionately more frequently for younger men than alprostadil injection or suppository. Alprostadil was prescribed proportionately more frequently by urologists than sildenafil, which was most commonly prescribed by family and general practitioners, and internists. The data indicate the wide adoption and use of sildenafil for erectile dysfunction.

Use of isotretinoin (Accutane) in the United States: rapid increase from 1992 through 2000.

BACKGROUND: Isotretinoin, a drug approved to treat severe recalcitrant nodular acne, has been marketed in the United States since 1982. The drug is an effective treatment for acne that is refractory to other therapies, but it is a teratogen and can cause serious side effects. OBJECTIVE: Our purpose was to describe trends in the use of isotretinoin in the United States from marketing through year 2000 and summarize characteristics of patients and prescribers. METHODS: Data from 2 pharmaceutical marketing research databases, the National Prescription Audit Plus and the National Disease and Therapeutic Index, and from 2 health plan networks were obtained and analyzed. RESULTS: Retail pharmacies dispensed 19.8 million outpatient prescriptions for isotretinoin from marketing in 1982 through 2000. From 1983 through 1993, the median annual number of prescriptions was just over 800,000; between 1992 and 2000, the number of prescriptions increased 2.5-fold (250%) to nearly 2 million in year 2000. The increases registered in the health plans were somewhat larger: about 275% increases from 1995 through 1999. There is no ICD-9 code for nodulocystic acne; consequently, the type of acne treated with isotretinoin is not determinable from these data. However, between 1993 and 2000, the proportion of isotretinoin treatment for severe acne declined from 63% to 46%, whereas the proportion of treatment for mild and moderate acne increased from 31% to 49%. Data also indicated that the sex distribution of patients was nearly even, and that 63% of male patients prescribed isotretinoin were 15 to 19 years old, whereas 51% of female patients were 15 to 24 years old. CONCLUSION: In the last 8 years, there has been a 2.5-fold (250%) increase in the number of dispensed prescriptions for isotretinoin in the United States. Data also reveal an increasing proportion of isotretinoin use for mild and moderate acne.