First-Trimester Exposure to Gadolinium-based Contrast Agents: A Utilization Study of 4.6 Million U.S. Pregnancies.

BackgroundThe safety of gadolinium-based contrast agent (GBCA) exposure during pregnancy has not been established, and the use of GBCAs during pregnancy is not recommended unless it is essential to the health of the woman or fetus.PurposeTo examine the prevalence of GBCA exposure in a large sample of pregnancies resulting in a live birth.Materials and MethodsThe Sentinel Distributed Database was used to retrospectively identify U.S. pregnancies that resulted in live births between 2006 and 2017 from 16 data partners. The main outcome was the prevalence of MRI procedures with and without GBCAs, sorted by anatomic location and trimester, among pregnant and matched comparator women.ResultsAmong 4 692 744 pregnancies resulting in a live birth, we identified 6879 exposures to GBCAs in 5457 pregnancies, representing one contrast-enhanced MRI examination per 860 pregnancies (0.12% of all pregnancies). Most contrast-enhanced MRI examinations were performed in the head (n = 3499), although pelvic and abdominal MRI constituted 22.3% (n = 1536) of all contrast-enhanced MRI examinations during pregnancy. The majority (70.2%) of GBCA exposures occurred during the first trimester, with a 4.3-fold greater prevalence compared with that in the second trimester and a 5.1-fold greater prevalence compared with that in the third trimester.ConclusionThis study identified higher rates of gadolinium-based contrast agent (GBCA) exposure during the first few weeks of pregnancy compared with the later weeks of pregnancy, suggesting inadvertent exposure to GBCAs might occur before pregnancy is recognized.© RSNA, 2019Online supplemental material is available for this article.See also the editorial by Kallmes and Watson in this issue.

Evaluation of Switching Patterns in FDA's Sentinel System: A New Tool to Assess Generic Drugs.

INTRODUCTION: Nearly 90% of drugs dispensed in the US are generic products. OBJECTIVE: The aim of this study was to develop and implement a tool for analyzing manufacturer-level drug utilization and switching patterns within the US Food and Drug Administration's Sentinel system. METHODS: A descriptive tool was designed to analyze data in the Sentinel common data model and was tested with two case studies-metoprolol extended release (ER) and lamotrigine ER-using claims data from four Sentinel data partners. We plotted initiators of each brand and generic product over time. For metoprolol ER, we evaluated rates of switching from generics around the time of manufacturing issues. For lamotrigine ER, we examined rates of switching back to the brand among those who switched from brand to generic. RESULTS: We identified 1,651,285 initiators of metoprolol ER products between July 2008 and September 2015. We observed a large decrease in monthly metoprolol ER initiators (from 25,465 in December 2008 to 13,128 in February 2009), corresponding to recalls by generic manufacturers. We observed simultaneous increases in utilization of the authorized generic and brand products. We identified 4266 initiators of lamotrigine ER with an epilepsy diagnosis between January 2012 and September 2015. Among those who switched from brand to generic, the cumulative incidence of switching back was close to 20% at 2 years. Switchback rates were higher for the first available generic products. CONCLUSIONS: This developed tool was able to elucidate novel utilization and switching patterns in two case studies. Such information can be used to support surveillance of generic drugs and biosimilars.

Antiemetic use among pregnant women in the United States: the escalating use of ondansetron.

PURPOSE: To examine ondansetron use in pregnancy in the context of other antiemetic use among a large insured United States population of women delivering live births. METHODS: We assessed ondansetron and other antiemetic use among pregnant women delivering live births between 2001 and 2015 in 15 data partners contributing data to the Mini-Sentinel Distributed Database. We identified live birth pregnancies using a validated algorithm, and all forms of ondansetron and other available antiemetics were identified using National Drug Codes or procedure codes. We assessed the prevalence of antiemetic use by trimester, calendar year, and formulation. RESULTS: In over 2.3 million pregnancies, the prevalence of ondansetron, promethazine, metoclopramide, or doxylamine/pyridoxine use anytime in pregnancy was 15.2, 10.3, 4.0, and 0.4%, respectively. Ondansetron use increased from <1% of pregnancies in 2001 to 22.2% in 2014, with much of the increase attributable to oral ondansetron beginning in 2006. Promethazine and metoclopramide use increased modestly between 2001 (13.8%, 3.2%) and 2006 (16.0%, 6.0%) but decreased annually through 2014 (8.0%, 3.2%). Doxylamine/pyridoxine, approved for management of nausea and vomiting in pregnancy in 2013, was used in 1.8% of pregnancies in 2014. For all antiemetics, use was highest in the first trimester. CONCLUSIONS: We observed a marked increase in ondansetron use by study year, prescribed to nearly one-quarter of insured pregnant women in 2014, occurring in conjunction with decreased use of promethazine and metoclopramide. Given the widespread use of ondansetron in pregnancy, data establishing product efficacy and methodologically rigorous evaluation of post-marketing safety are needed. Published 2017. This article is a U.S. Government work and is in the public domain in the USA.

Use of Prescription Drug Samples in the USA: A Descriptive Study with Considerations for Pharmacoepidemiology.

INTRODUCTION: Free prescription drug samples provided in physician offices can lead to exposure misclassification in pharmacoepidemiologic studies that rely on pharmacy claims data. METHODS: We quantified drug-specific sample provision rates based on nationally projected data from a survey of over 3200 US office-based physicians for 1993-2013. RESULTS: Between 2009 and 2013, a total of 44.7 % of newly initiated brand-only sitagliptin but only 3.6 % of generically available metformin therapy was provided as samples. We observed similar discrepancies between newly initiated rosuvastatin and simvastatin, dabigatran and warfarin, atomoxetine and methylphenidate, and between oral antibiotic drugs. During continued therapy, sample use was still present though to a lesser extent (sitagliptin 17.0 %, rosuvastatin 23.9 %), and remained high for some oral contraceptives (norethindrone 55.8 %). Oral contraceptives had the longest average days of sample supply (levonorgestrel, continued use 85.1 days). The average days of supply for all other chronically used study drugs ranged from 13.4 (dabigatran, new use) to 25.3 (exenatide, continued use) per sample provided. From 1993 to 2013, we found pronounced drops in sample provisions over time coinciding with more recent generic approval dates. CONCLUSIONS: We observed markedly differential exposure to medication samples between branded and generic drugs. This can introduce bias in pharmacoepidemiologic studies, especially when adverse events that occur soon after drug initiation are of interest.

Trends in osteoporosis treatment with oral and intravenous bisphosphonates in the United States, 2002-2012.

Bisphosphonates have been widely prescribed to postmenopausal women for treatment and prevention of osteoporosis. Given a background of reports of recent safety problems, questions about optimal duration of use, and the patent expiration of Fosamax in February 2008, we accessed data from pharmaceutical marketing research databases to describe trends in dispensed prescriptions and sales of oral bisphosphonates, characteristics of patients and prescribers, and sales of intravenous bisphosphonates for osteoporosis treatment. An estimated 21.3million prescriptions for oral bisphosphonates were dispensed in U.S. retail pharmacies in 2002 that increased 46% to a peak of 31.0million in 2007 and 2008, and declined by 53% in a four year-period to 14.7million in 2012. Sales data (number of packages sold in all settings of care) showed parallel trends (66% increase from 2002 through 2007 and 51% decrease from 2007 through 2012). Similarly, intravenous bisphosphonate sales for osteoporosis treatment grew 3.8-fold from 149.5 thousand packages in 2007 to 561.6 thousand in 2010, followed by a 22% decrease in 2012. Data from an ongoing monthly office-based survey indicated physicians mentioned oral bisphosphonates primarily in visits of older aged Caucasian women with lower body mass for osteoporosis. Frequencies of oral bisphosphonate mentions increased between 2002 and 2012 in visits of Asians and for osteopenia diagnoses. These data indicate a substantial decline in prescriptions and sales of oral (since 2007-2008) and intravenous (since 2010) bisphosphonates for osteoporosis treatment in the United States. Reasons for, and implications of, the decline should be considered for future research.