Generic drug discount programs: are prescriptions being submitted for pharmacy benefit adjudication?

UNLABELLED:   BACKGROUND: In 2006, pharmacies began offering select generic prescription drugs at discount prices (e.g., $4 for a 30-day supply) through nonmembership and membership programs. As part of the contract in membership generic drug discount programs, the member agrees to forgo submission of the claim to the insurance company. Claims not submitted for insurance adjudication may result in incomplete pharmacy benefit manager (PBM) and health plan data, which could negatively influence adherence reporting and clinical programs. To address potentially missing claims data, the Centers for Medicare Medicaid Services (CMS) encourages Medicare Part D sponsors to incentivize network pharmacies to submit claims directly to the plan for drugs dispensed outside of a member's Part D benefit, unless a member refuses. The extent of PBM and health plan claims capture loss due to generic drug discount programs is unknown. OBJECTIVE: To identify changes in levothyroxine utilizers' prescription claims capture rate following the advent of generic drug discount membership and nonmembership programs. METHODS: This retrospective concurrent cohort study used claims data from 3.5 million commercially insured members enrolled in health plans located in the central and southern United States with Prime Therapeutics pharmacy benefit coverage. Members were required to be 18 years or older and younger than 60 years as of January 1, 2006, and continuously enrolled from January 1, 2006, through December 31, 2010. Members utilizing generic levothyroxine for at least 120 days during January 1, 2006, through June 30, 2006 (baseline period) from the same pharmacy group with supply on July 1, 2006, were placed into 1 of 3 pharmacy groups: (1) nonmembership (Walmart, Sam's Club, Target, Kroger, City Market, and King Soopers pharmacies), (2) membership (Walgreens, CVS, Albertsons, and Savon pharmacies), or (3) the reference group of all other pharmacies. The index date was defined as July 1, 2006. The levothyroxine claim providing supply on July 1, 2006, was the index claim. Members with a Kmart pharmacy index claim were excluded, since the Kmart membership drug discount program began prior to July 1, 2006. Levothyroxine claims capture nonpersistency, defined as the occurrence of a claim supply end date prior to a 180-day gap, was the primary outcome variable and was assessed from July 1, 2006, through June 30, 2010 (follow-up period). The odds of levothyroxine claims capture nonpersistency by pharmacy group were assessed using a logistic regression analysis adjusted for the following covariates: age, gender, median income in the ZIP code of residence (binomial for ≤ $50,000 vs. greater than $50,000), switch to a brand levothyroxine product during the follow-up period, index levothyroxine claim supply of 90 days or more, and index levothyroxine claim member cost share per 30-day supply in tertiles (≤ $5.00, $5.01-$7.99, ≥ $8.00). RESULTS: Of 2,632,855 eligible members aged 18 years or older, 13,427 met all study eligibility criteria. The baseline pharmacy groups were membership with 3,595 (26.8%), nonmembership with 1,919 (14.3%), and all other pharmacies with 7,913 (58.9%) members. The rates of levothyroxine claims capture persistency throughout the 4-year follow-up period were 85.4% for nonmembership (P = 0.593 vs. all other pharmacies), 77.7% for the membership group (P less than 0.001 vs. all other pharmacies), and 85.9% for all other pharmacies. The Kaplan-Meier comparison of claims capture persistency found nearly identical claims capture loss for the nonmembership compared with all other pharmacies group, and when compared in a multivariate logistic regression model, there was no difference in the odds of levothyroxine claims capture over 4 years follow-up (OR = 1.01, 95% CI = 0.88-1.16, P = 0.900). The membership generic drug discount programs (Walgreens, CVS, Alberstons, and Savon pharmacies) had a statistically significant 61% higher odds (OR = 1.61, 95% CI = 1.45-1.79, P less than 0.001) of levothyroxine claims capture nonpersistency. The onset of the difference between the membership group and the all other pharmacies group was temporally associated with the launch of the membership programs. In comparison to index levothyroxine member cost of ≤ $5.00 per 30-day supply, higher cost shares were associated with higher levothyroxine claims capture nonpersistency ($5.01 to $7.99 OR 1.34, 95% CI 1.19-1.52 and ≥ $8.00 OR 1.60, 95% CI 1.40-1.82). CONCLUSIONS: Among levothyroxine utilizers in 2006 (prior to the advent of drug discount programs), those with claims from a pharmacy that subsequently implemented a nonmembership generic drug discount program did not appear to have a different rate of levothyroxine claims capture than members from the reference group when followed through June 2010. Utilizers with claims from a pharmacy that subsequently implemented a membership program had a significantly lower levothyroxine claims capture rate. Increasing index levothyroxine member cost was associated with higher levothyroxine claims capture loss. Because the analysis could not directly measure claims capture loss associated with members who switched to a new pharmacy group without presenting their insurance information (e.g., membership discount programs), further research is needed to confirm these findings.

Formulary management of the protease inhibitors boceprevir and telaprevir for chronic hepatitis C virus.

BACKGROUND: Hepatitis C virus (HCV) is the most common chronic bloodborne illness in the United States. The incidence of acute hepatitis C in the United States peaked near 50,000 cases in the late 1980s but has stabilized since 2003 to less than 5,000 cases annually. The combination of pegylated interferon (peginterferon) and ribavirin has been the standard recommended treatment for HCV. Protease inhibitors telaprevir and boceprevir were approved by the FDA in May 2011 for the treatment of hepatitis C genotype 1 in combination with peginterferon and ribavirin. OBJECTIVE: To review the phase 3 trials for telaprevir and boceprevir and provide managed care considerations. METHODS: A MEDLINE review was performed for articles published and available through September 15, 2011, using keywords "boceprevir" or "telaprevir" with an emphasis on phase 3 trials. The literature search was limited to articles in English, clinical trials, randomized controlled trials, and research conducted in humans. Additional information was obtained from the FDA website. RESULTS: Three phase 3 trials are available for telaprevir, which provided data that were the basis for FDA approval. Boceprevir demonstrated efficacy and safety in 2 pivotal phase 3 trials. Both agents demonstrated statistically significantly higher rates of virologic response compared with the standard of care involving peginterferons and ribavirin. Telaprevir and boceprevir also demonstrated efficacy in the treatment of patients who had previously failed dual therapy for hepatitis C. Safety concerns for both agents include anemia, drug interactions, skin rashes, and gastrointestinal adverse events. CONCLUSIONS: Decision makers have many factors to consider in developing a strategy around hepatitis C. Increased drug costs, patient management, adherence, comparative safety and efficacy, and appropriate utilization management controls are important issues. Payers may consider developing clinical programs to encourage adherence and appropriate use and leverage an appropriate channel to ensure cost-effective therapy.

Formulary review of 2 new biologic agents: tocilizumab for rheumatoid arthritis and ustekinumab for plaque psoriasis.

BACKGROUND: Two autoimmune biologics were recently approved by the FDA: ustekinumab in September 2009 for the treatment of moderate to severe plaque psoriasis in adults who are candidates for phototherapy or systemic therapy and tocilizumab in January 2010 for adult patients with moderate to severe rheumatoid arthritis (RA) who have not responded adequately to 1 or more tumor necrosis factor (TNF) antagonist therapies. Both agents use new mechanisms of action and add to the growing group of autoimmune biologics. OBJECTIVE: To critically review the phase 3 trials for ustekinumab and tocilizumab and provide managed care considerations in the context of the 9 other biologic agents on the market in the United States that are used to treat moderate to severe RA or psoriasis. METHODS: A MEDLINE review was performed for articles published and available through January 2010 using keywords "ustekinumab" and "tocilizumab" with an emphasis on phase 3 trials. The literature search was limited to articles in English, clinical trials, randomized controlled trials, and research conducted in humans. Search results for ustekinumab included 8 articles of which 4 were excluded for not being psoriasis or psoriatic arthritis trials. Search results for tocilizumab included 16 articles of which 8 were excluded for not being RA trials or using biomarkers as primary endpoints. Additional information was obtained from the FDA website. RESULTS: Three phase 3 trials are available for ustekinumab. Ustekinumab demonstrated superior efficacy to placebo in 2 trials for the treatment of psoriasis. In a 12-week trial, ustekinumab 45 milligrams (mg) and 90 mg demonstrated significantly higher rates of 75% improvement in the psoriasis area and severity index (PASI 75) (67.5% and 73.8%, respectively) compared with etanercept (56.8%) in the first phase 3 comparative psoriasis trial between autoimmune biologics (P < 0.05 for both comparisons). In a phase 3 trial of RA patients who had failed prior TNF antagonist therapy, a 20% improvement in signs or symptoms according to the American College of Rheumatology criteria (ACR 20) at week 24 was achieved by significantly more study participants in the tocilizumab 8 mg per kilogram (kg) (50.0%) and 4 mg per kg (30.4%) groups than the placebo group (10.1%, P < 0.001 for both tocilizumab groups compared with placebo). Safety data for ustekinumab are limited to use for less than 2 years, and the prescribing information contains warnings regarding infection and malignancy. Tocilizumab is associated with neutropenia, thrombocytopenia, and elevations in lipids and liver function tests. Tocilizumab has unique adverse events when compared with other autoimmune biologics and requires laboratory testing and careful monitoring. CONCLUSIONS: Ustekinumab and tocilizumab are new additions to the treatment of autoinflammatory disease. The majority of safety data for both agents are from trials lasting 3 to 6 months. Published long-term safety data for tocilizumab are limited to less than 143 patients treated longer than 5 years, and safety data for ustekinumab are scant beyond 2 years of use; therefore, clinicians should exercise caution prior to widespread adoption. The comparative efficacy and safety trial of etanercept and ustekinumab brings important clinical information to decision makers. Tocilizumab is indicated after failure or intolerance to a TNF antagonist and has unique safety concerns. Managed care plans will consider the experience and long-term data of these agents along with efficacy data and cost when establishing management programs such as prior authorization or step therapy.

Dronedarone: current evidence and future questions.

Atrial fibrillation (AF) is the most common sustained arrhythmia, affecting more than 2.2 million Americans. ACC/AHA/ESC guidelines for the management of patients with AF recommend amiodarone for maintaining sinus rhythm. Dronedarone is a derivative of amiodarone indicated for the treatment of AF. To provide an overview of dronedarone with a focus on the phase III trials and discuss unresolved questions of dronedarone. A literature search was conducted via the PubMed database using the keyword "dronedarone." Search was limited to human trials in english. The FDA website was searched for briefing documents and subcommittee meetings on dronedarone. Clinicaltrials.gov was searched with the keyword dronedarone for upcoming or unpublished clinical trials. Five phase III trials are available for dronedarone: ANDROMEDA, EURIDIS/ADONIS, ATHENA, ERATO, and DIONYSIS. EURIDIS/ADONIS and ATHENA demonstrated a reduction AF recurrence with dronedarone compared to placebo. The ANDROMEDA trial recruited patients with recent hospitalization for heart failure and was terminated due to an excess of deaths in the dronedarone group. The DIONYSIS trial was a comparative effectiveness trial that demonstrated less efficacy for dronedarone but improved tolerability compared to amiodarone. Dronedarone represents an option in the management of AF in select patients. Dronedarone is not appropriate in patients with recently decompensated heart failure or those treated with strong CYP3A4 inhibitors or medications prolonging the QT interval. Dronedarone appears to have improved tolerability at the expense of decreased efficacy when compared to amiodarone. Questions remain on the long-term safety, use in patients with heart failure, retreatment after dronedarone or amiodarone failure, and comparative efficacy with a rate control strategy.

Association of prescription abandonment with cost share for high-cost specialty pharmacy medications.

BACKGROUND: In 2008, specialty medications accounted for 15.1% of total pharmacy benefit medication spending, and per member expenditures have increased by 11.1% annually from 2004 to 2008 within a commercially insured population of 8 million members. Insurers face increasing pressure to control specialty medication expenditures and to rely on increasing member cost share through creation of a fourth copayment tier within the incentive-based formulary pharmacy benefit system. Data are needed on the influence that member out-of-pocket (OOP) expense may have on prescription abandonment (defined as the patient never actually taking possession of the medication despite evidence of a written prescription generated by a prescriber). OBJECTIVE: To explore the relationship between prescription abandonment and OOP expense among individuals newly initiating high-cost medication therapy with a tumor necrosis factor (TNF) blocker or multiple sclerosis (MS) biologic agent. METHODS: This observational cross-sectional study queried a midwestern and southern U.S. database of 13,172,480 commercially insured individuals to find members with a pharmacy benefit-adjudicated claim for a TNF blocker or MS specialty medication during the period from July 2006 through June 2008. Prescription abandonment was assessed among continuously enrolled members newly initiating TNF blocker or MS therapy. Prescription abandonment was defined as reversal of the adjudicated claim with no evidence of a subsequent additional adjudicated paid claim in the ensuing 90 days. Separate analyses for MS and TNF blocker therapy were performed to assess the association between member OOP expense and abandonment rate using the Cochran-Armitage test for trend and multivariate logistic regression. Members were placed into 1 of the 7 following OOP expense groups per claim: $0-$100, $101-$150, $151-$200, $201-$250, $251-$350, $351-$500, or more than $500. The association of MS or TNF blocker abandonment rate with OOP expense was tested with logistic regression models using the $0-$100 OOP as the reference group and adjusting for age, gender, formulary status, ZIP code-level income and education, earliest specialty medication claim, and methotrexate use for the TNF blocker analysis. RESULTS: Of 2,791 members presenting a prescription to newly initiate high-cost MS therapy, 1,985 (71.1%) of the claims were for a 1-month supply with most of the remainder for a 3-month supply; 2,303 (82.5%) had an OOP expense of $0-$100, and 5.4% had an OOP expense greater than $500. The abandonment rate increased as OOP increased (test for trend, P < 0.001). Members with an OOP expense of $100 or less had an abandonment rate of 5.7%. Among members in all OOP expense groups greater than $200, the abandonment rate was significantly higher, with more than 1 in 4 members abandoning their MS claims (P < 0.001). In the multivariate logistic regression analysis, the abandonment rate became significantly higher at OOP expenses of $201 to $250 compared with an OOP expense of $100 or less (odds ratio [OR] = 7.3, 95% confidence interval [CI] = 3.3- 16.2). The odds ratios ranged between 6.1 and 7.3 for OOP expense groups greater than $200. Of 7,313 members presenting a prescription to newly initiate TNF blocker therapy, 5,809 (79.4%) of claims were for a 1-month supply with most of the remainder for a 3-month supply; 6,123 (83.7%) had an OOP expense of $0-$100 and 5.7% had an OOP expense greater than $500. The abandonment rate increased as OOP expense increased (test for trend, P < 0.001). In the multivariate logistic regression analysis, the TNF blocker medication abandonment rate was significantly higher for all OOP expense groups greater than $100, with abandonment odds ratios of 2.3 to 4.4 for OOP expense between $101 and $500 compared with OOP expense of $0-$100. The odds of abandonment at OOP expense of greater than $500 were 7-fold higher (OR = 7.0, 95% CI = 5.4-9.1). CONCLUSIONS: This is the first study to perform a focused assessment of an association between specialty medication OOP expense and new therapy prescription abandonment. The study found that per claim OOP expenses greater than $100 for TNF blocker medication and greater than $200 for MS medication were associated with increased prescription abandonment. These findings coupled with previous research identifying a negative relationship between OOP expense above $100 per month and adherence, and the commercial insurance market response to fourth-tier OOP expenses, suggests that insurers should consider the impact that specialty OOP expense may have on adherence and member satisfaction. Further prospective research should be performed to confirm these findings and assess the clinical outcomes associated with prescription abandonment.

Critical review of prasugrel for formulary decision makers.

BACKGROUND: Cardiovascular disease, including acute coronary syndromes (ACS) comprising ST-elevation and non-ST-elevation myocardial infarction (STEMI/NSTEMI) and unstable angina (UA), remains the leading cause of death in the United States. The direct and indirect costs of cardiovascular disease are estimated to surpass $165 billion in 2009. Antiplatelet pharmacotherapy has been shown to reduce ACS-related death and is part of the American College of Chest Physicians (ACCP) and the American College of Cardiology /American Heart Association (ACC/AHA) treatment guideline recommendations. OBJECTIVE: To provide formulary decision makers with information on the pharmacokinetics and pharmacodynamics of the thienopyridine antiplatelet agent prasugrel as well as an analysis of available efficacy and safety data and its risk-benefit profile in comparison with clopidogrel. METHODS: Literature search for information on prasugrel with a focus on (a) the Trial to Assess Improvement in Therapeutic Outcomes by Optimizing Platelet Inhibition with Prasugrel-Thrombolysis in Myocardial Infarction (TRITON-TIMI) 38 trial, (b) briefing documents from the FDA available as of March 1, 2009, and (c) ongoing phase III studies of prasugrel. RESULTS: TRITON-TIMI 38 was a double blind, randomized superiority study involving 13,608 patients with moderate-to high-risk acute coronary syndromes with scheduled percutaneous coronary intervention (PCI). TRITON-TIMI 38 data were available in a published manuscript and in an FDA review. Study patients were randomized to either prasugrel or clopidogrel once daily. The primary end point (composite of death from cardiovascular causes, nonfatal myocardial infarction, or nonfatal stroke) occurred in 643 patients (9.9%) in the prasugrel group and 781 patients (12.1%) in the clopidogrel group (HR = 0.82, 95% CI = 0.73-0.93, P = 0.002). Non-coronary artery bypass graft (non-CABG) TIMI major hemorrhage occurred in 146 patients (2.4%) in the prasugrel group compared with 111 patients (1.8%) in the clopidogrel group (HR=1.32, 95% CI=1.03-1.68, P = 0.03). A subanalysis of the TRITON-TIMI 38 trial data revealed a net harm for patients with a prior history of stroke or transient ischemic attack (TIA) when treated with prasugrel (HR = 1.54, 95% CI = 1.02-2.32, P = 0.04). Combination prasugrel and aspirin is currently being studied in comparison with clopidogrel and aspirin for the treatment of UA/NSTEMI patients that are medically managed. CONCLUSIONS: For every 1,000 patients treated with prasugrel instead of clopidogrel, a total of 24 end points would be prevented at the cost of 10 additional bleeding events. On February 3, 2009, the FDA Cardiovascular and Renal Drugs Advisory Committee deemed this to be an acceptable riskbenefit profile. The committee recommended a label contraindication for patients with prior history of transient ischemic attack or stroke. Treatment versus time analyses demonstrated both early and sustained benefit for prasugrel compared with clopidogrel. However, prasugrel was associated with fewer cardiovascular events prevented per bleeding case the longer the duration of therapy. The study population of TRITON-TIMI 38 was limited to patients undergoing PCI. Managed care decision makers should consider specific criteria limiting prasugrel use to health plan members with characteristics similar to the study population in TRITON-TIMI 38 that benefited from treatment and avoiding use in patients with prior history of stroke or TIA. More data are needed before prasugrel can be recommended in patient groups not addressed by TRITON-TIMI 38.

Rosiglitazone and pioglitazone utilization from January 2007 through May 2008 associated with five risk-warning events.

BACKGROUND: Rosiglitazone was approved by the U.S. Food and Drug Administration (FDA) for type 2 diabetes in 1999. The unique mechanism of action and low risk of hypoglycemia contributed to rapid market uptake of rosiglitazone, but safety concerns became more prominent in 2007. There were 5 major events on 4 calendar days in 2007 regarding safety concerns related to rosiglitazone in certain patients: (1) the May 21, 2007, online release of the rosiglitazone meta-analysis performed by Nissen and Wolski and the FDA safety warning on the same day; (2) the July 30, 2007, conclusion of an FDA advisory committee meeting that rosiglitazone increased cardiac ischemic risk; (3) the August 14, 2007, update of thiazolidinedione (TZD) labels with a black-box warning for heart failure; and (4) the November 14, 2007, update to the warnings and precautions section of the rosiglitazone label for coadministration of nitrate or insulin. OBJECTIVES: To (1) describe TZD (rosiglitazone and pioglitazone) utilization trends from January 1, 2007, continuing through May 2008 amid public announcements of safety concerns and (2) determine the percentage of TZD users who had medical claims indicating increased cardiovascular (CV) risk before and after release (May 21, 2007) of the FDA safety warning and online release of the meta-analysis performed by Nissen and Wolski. METHODS: A retrospective analysis of pharmacy claims was performed from 9 commercial plans with a combined 9 million eligible members, including a 1.4 million-member cohort from 1 of the plans for which medical claims data were available. We evaluated trends in TZD use for each month for the 17-month period from January 1, 2007, through May 31, 2008, including the percentage of TZD users at increased CV risk. In the trend analysis, for each calendar month of 2007, we calculated mean pharmacy claim counts per day per million members for each of the 2 TZD drugs and for a comparison drug, sitagliptin, a new oral hypoglycemic agent in a different class (dipeptidyl-peptidase-IV inhibitors). For the CV risk analysis, we used the database of integrated medical and pharmacy claims for the 1.4 million-member cohort to identify patients with a current days supply of a TZD on May 20, 2007, December 7, 2007, or May 20, 2008. The medical claims for all identified patients were queried back 2 years from May 20, 2007, December 7, 2007, or May 20, 2008, respectively. Rosiglitazone users at increased CV rsk were defined as those with a medical claim with a primary diagnosis for congestive heart failure (CHF; International Classification of Diseases, Ninth Revision, Clinical Modification [ICD-9-CM] codes 428.xx or 398.91), those with a current supply of nitrate or insulin therapy, or those with ischemic heart disease, including myocardial infarction (MI; ICD-9-CM codes 410.xx through 414.xx, or surgical procedure codes [36.0x through 36.3x for removal of obstruction and insertion of stents, bypass surgery, and revascularization] in the primary diagnosis field). Pioglitazone users at increased risk were identified from medical claims with a CHF diagnosis code. RESULTS: The average number of claims per day per million members in January 2007 was 97.3 for rosiglitazone and 107.2 for pioglitazone. The average number of claims for rosiglitazone per day per million members began to decrease in May 2007, falling to 41.0 in December 2007, for a total decrease of 58.6% from the February 2007 peak (99.1), and fell further to 31.8 in May 2008. Pioglitazone use increased 8.0% from January to June 2007 (107.2 to 115.8) and remained relatively flat through December 2007 (114.6) and through May 2008 (108.9). Sitagliptin claims increased 5-fold, at a consistent rate, from an average of 8.6 claims per day per million members in January 2007 to 43.4 in December 2007, and continued to increase to 48.7, in May 2008. Of the 5,117 rosiglitazone users on May 20, 2007, 1,296 (25.3%) were identified at increased CV risk versus 590 (22.5%) of 2,621 users on December 7, 2007 (P = 0.006), and 336 (21.8%) of 1,541 users in May 2008 (P = 0.005). Of 6,056 pioglitazone users on May 20, 2007, 170 (2.8%) had a CHF diagnosis versus 160 (2.5%) of 6,275 users on December 7, 2007 (P = 0.376), and 122 of 5,998 users in May 2008 (P = 0.006). CONCLUSIONS: Although rosiglitazone utilization per million members declined by more than half in 2007, when CV safety concerns started to emerge, about 1 in 5 rosiglitazone users had elevated CV risk at year-end 2007 and in May 2008. About 3% of pioglitazone users in May 2007 had a diagnosis of CHF in claims history, which declined to 2% in May 2008. Insurers should consider the impact of persistent utilization of TZDs among members with CV risk factors when making formulary decisions.

Telithromycin: the perils of hasty adoption and persistence of off-label prescribing.

BACKGROUND: Telithromycin (Ketek) was approved in April 2004 for the treatment of acute bacterial exacerbations of chronic bronchitis (ABECB), bacterial sinusitis, and community-acquired pneumonia. The approval of telithromycin was controversial due to trial irregularities, noninferiority study designs, and use of foreign safety data. Safety concerns involving hepatotoxicity, myasthenia gravis exacerbation, and visual disturbances were increasingly documented in the literature after approval. On February 12, 2007, the U.S. Food and Drug Administration (FDA) removed the bacterial sinusitis and ABECB indications and strengthened safety warnings for telithromycin. OBJECTIVE: To (1) assess the prevalence and distribution of on-label telithromycin utilization before and after the revisions of the product label and (2) assess the association of pivotal events in the life cycle of telithromycin with its use as reflected in pharmacy and medical claims. METHODS: Using retrospective administrative medical and pharmacy claims from a large midwestern commercial insurer with an eligible membership of 1.8 million members, individuals with a telithromycin claim during January 1, 2007, through April 13, 2007, were identified. Their medical claims within 30 days prior to or on the initial telithromycin claim were analyzed for the presence of an on-label diagnosis code. Monthly telithromycin and clarithromycin claim totals per million members from January 2004 through March 2007 were calculated. Claim totals were plotted to identify utilization trends in relation to the FDA health advisory for telithromycin on January 20, 2006, and the telithromycin label changes on February 12, 2007. RESULTS: The medical diagnosis analysis consisted of 507 members with 1 or more medical claims with dates of service within 30 days of at least 1 pharmacy claim for telithromycin. Using the original approved telithromycin indications, 52.3% (256 of 507) of telithromycin use was on-label. The most common on-label diagnoses were sinusitis (33.9%) and bronchitis (14.4%). A diagnosis of pneumonia was present for 3.9% of telithromycin utilizers. After the February 12, 2007, label change limiting telithromycin to community-acquired pneumonia, on-label use was 6.7% (12 of 179) of utilizers. Telithromycin claims were first detected in August 2004 and overtook the clarithromycin rate of 729 claims per million members in January 2005, reaching a peak rate of 940 claims per million members in January 2006. Telithromycin monthly claims remained higher than clarithromycin until April 2006, 3 months after the liver toxicity health advisory. In comparison with January 2006, the January 2007 telithromycin claims were 186 claims per million members, a decrease of 80%. CONCLUSION: Despite revised FDA indications and safety warnings, fewer than 1 in 15 active telithromycin users have a medical claim consistent with the only currently approved indication (pneumonia). Pharmacy claims for telithromycin dropped substantially following reports of severe hepatotoxicity and strengthened safety warnings. The high prevalence of telithromycin off-label use despite hepatotoxicity and other safety risks is cause for continued concern.

Penicillin allergy skin testing: what do we do now?

Drug-induced anaphylaxis remains a relatively infrequent event. However, penicillin and associated beta-lactam antibiotics remain a primary cause of anaphylaxis. Penicillin allergies are undoubtedly overreported, and patients with suspected penicillin allergy can be treated with antibiotic alternatives. Penicillin allergy skin testing is a simple and effective way to identify true penicillin allergy. Skin testing involves testing for both major and minor determinants and should be conducted in a facility with available life-support equipment. The commercial major determinant product, benzylpenicilloyl-polylysine, was removed from the market in 2004; this action compromised the ability of clinicians to evaluate a patient's likely response to penicillin therapy. Alternatives to skin testing include laboratory synthesis of major determinants, use of the radioallergosorbent test (RAST), or a combination of RAST and minor determinant skin testing. Patients with suspected penicillin allergy can undergo desensitization if they require penicillin therapy. The planned return of a commercial major determinant will hopefully resolve this issue.

Consistent rates of kill of Staphylococcus aureus by gentamicin over a 6-fold clinical concentration range in an in vitro pharmacodynamic model (IVPDM).

OBJECTIVES: To compare the effect of a 6-fold range in gentamicin concentration on the bacterial killing of Staphylococcus aureus. METHODS: Six 24 h duplicate experiments were performed using an in vitro pharmacodynamic model (IVPDM) which was inoculated with 10(6) cfu/mL S. aureus (ATCC 29213) and subjected to desired initial gentamicin concentrations of 0, 5, 10, 15 and 20 mg/L. A 2 h half-life was emulated for gentamicin. Samples were drawn at 0.5, 1, 1.5, 2, 3, 4, 6, 9 and 24 h to quantify cfu/mL and gentamicin concentration. These samples were subjected to serial saline dilution to prevent antibiotic carryover and to produce a countable number of colonies. Pre- and post-gentamicin MIC values were performed for S. aureus. Duplicate 24 h kill curves were generated for each experiment and assessed for statistical difference (two-way ANOVA) between the slopes of the kill curves and time to 3 log kill. RESULTS: Kill curve slopes were analysed out to the 2 h time point and no statistical difference was found between the different concentrations (P > 0.05). Time to 3 log kill was not significantly different between the concentrations. Post-exposure gentamicin MIC values were within one tube dilution of the pre-exposure MIC value (0.25 mg/L). CONCLUSIONS: These data demonstrate that clinical gentamicin concentrations kill S. aureus with equivalent effectiveness and that the use of higher doses of aminoglycosides would probably not improve bacterial kill rates.