2005 Annual Meeting Annual
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S T C A R T American College of Clinical Pharmacy 2005 Annual Meeting October 23–26 . 2005 S San Francisco . California B A 1432 PHARMACOTHERAPY Volume 25, Number 10, 2005 hypoglycemic therapy is not required to experience this event. Clinicians ACCP Annual Meeting should consider this association when selecting antibiotic therapy for elderly diabetic patients. Presented at the 43rd Annual Meeting of the Infectious Diseases Society of October 23–26, 2005 America, San Francisco, CA, October 6–9, 2005. San Francisco, CA 3E. A 12-hour dosing interval reduces the pharmacokinetic interaction between simvastatin and telithromycin. G. Montay, PhD1, P. Chevalier, PhD1, C. Guimart, PhD1, M. Guillaume, MD2, V. Bhargava, PhD3; (1)sanofi-aventis, ORIGINAL RESEARCH 13 Quai Jules Guesde, 94400 Vitry sur Seine, France; (2)Aster-Cephac, Paris, These papers describe original research in therapeutics, pharmacokinetics, France; (3)sanofi-aventis, Bridgewater, NJ. pharmacodynamics, pharmacoeconomics, pharmacoepidemiology, and pharmacogenomics. PURPOSE: Pharmacokinetic (PK) interactions have been reported between simvastatin (SIM) and drugs that inhibit cytochrome P450 3A4, including macrolide and ketolide antibiotics. This open, randomized, crossover study ADR/Drug Interactions evaluated the extent of interaction following concomitant dosing of the ketolide telithromycin (TEL) and SIM vs dosing separated by a 12-hour interval (made possible as TEL can be administered once daily). 1. Adverse drug reactions in medicare patients: clinical and economic METHODS: Healthy adult males (n=14) received a single dose of SIM 40 mg outcomes of pharmacist provided ADR management programs. CA Bond, (Day 1), followed by TEL 800 mg once daily (Days 2–6). A further 40 mg Pharm.D., Cynthia L. Raehl; Texas Tech University Health Sciences Center dose of SIM was coadministered with TEL on Day 5, or administered 12 School of Pharmacy, Amarillo, TX. hours before the final TEL dose on Day 6. Plasma concentrations of SIM and its active metabolite SIM acid were measured for 24 hours after each dose. PURPOSE: This study examines adverse drug reactions (ADR) in 8,208,960 RESULTS: Compared with SIM alone, coadministration of TEL with SIM hospitalized Medicare patients in 1998. An analysis of the impact of having an significantly (p<0.0001) increased peak plasma concentration (Cmax) and area ADR, and the presence of pharmacist provided ADR management on clinical under the concentration–time curve (AUC(0–z)) of both SIM (7.7- and 8.5- and economic healthcare outcomes is provided. A database was constructed fold, respectively) and SIM acid (10.0- and 9.4-fold, respectively). Dosing of from the 1998 MedPAR database and the 1998 National Clinical Pharmacy TEL 12 hours after SIM decreased the magnitude of this effect by >50%: Cmax Services survey. for SIM/SIM acid by 3.4- and 3.2-fold and AUC(0–z) for SIM/SIM acid by 4.0- METHODS: The study population was composed of 141,398 Medicare and 4.3-fold, respectively. Study treatments were well tolerated. patients who experienced an ADRs (incidence 1.73%). The most common CONCLUSIONS: Coadministration of TEL with SIM significantly increases classes of medications associated with ADRs were cardiotonic glycosides, plasma levels of SIM/SIM acid. A 12-hour interval between SIM and TEL adrenal corticosteroids, antineoplastic agents, anticoagulants, and analgesics. administration reduces the magnitude of this interaction by >50%. This The most common diagnoses associated with ADRs were hypertension, represents an advantage of TEL over macrolides, which are dosed 2–4 times congestive heart failure, atrial fibrillation, volume depletion disorders, and daily. atherosclerotic heart disease. In patients developing an ADR, death rates were Presented at the 43rd Annual Interscience Conference on Antimicrobial 19.18% higher (odds ratio = 1.208, 95%CI (1.184,1.234), length of stay was Agents and Chemotherapy, Chicago, IL, September 14-17, 2003. 8.98% higher (t = 23.695, p<0.0001), total Medicare charges were 19.86% higher (t = 39.398, p<0.0001), drug charges were 9.15% higher (t = 12.374, 4E. Multidrug resistance-associated protein 2 inhibition by ritonavir p<0.0001, and laboratory charges were 2.82% higher (t = 5.888, p<0.0001). increases tenofovir-associated cytotoxicity. Jerika T. Lam, Pharm.D., Michael Pharmacist provided ADR management was evaluated in 1,945,296 patients N. Neely, M.D., Paul Beringer, Pharm.D., Stan G. Louie, Pharm.D.; University from 572 hospitals. In hospitals that did not have pharmacist provided ADR of Southern California (USC), Los Angeles, CA. management, the mean number of ADRs/100 admissions was 34.90% higher (odds ratio = 1.360, 95%CI (1.328, 1.392), death rates were 53.64% higher PURPOSE: This study evaluated the intracellular drug interaction between (odds ratio = 1.574, 95%CI (1.421,1.744), length of stay was 13.64% higher (t tenofovir (TFV) and ritonavir (RTV) and the role of multidrug resistance- = 2.349, p=0.019), total Medicare charges were 6.88% higher (t = 2.462, associated protein 2 (MRP2) in renal cytotoxicity so to 1) compare the p=0.015), and drug charges were 8.16% higher (t = 3.127, p=0.002). This is findings to documented clinical case reports of TFV in renal dysfunction, the first study to evaluate the incidence of ADRs in hospitalized Medicare with the majority of cases in patients receiving both TFV and RTV-containing patients. regimens, and 2) explore the intracellular mechanism(s) for the drug interaction. 2E. Rate of early-onset hypoglycemia associated with gatifloxacin in elderly METHODS: Madin-Darby Canine Kidney (MDCK) epithelial cell line and its patients. Mark C. Decerbo, Pharm.D., BCPS1, Jingyang Fan, Pharm.D., BCPS1, overexpressing MRP2 (MDCK-MRP2) variants were exposed to TFV, RTV, or Alan L. Greenberg, MD2; (1)University of Southern Nevada College of lopinavir (LPV) alone at concentrations ranging from 10 µg/ml to 1000 Pharmacy, Henderson, NV; (2)University of Nevada School of Medicine, Las µg/ml. In addition, TFV 10 µg/mL was combined with increasing Vegas, NV. concentrations of RTV and other MRP2 inhibitors such as LPV, cyclosporine (CSA), and MK571. MDCK and MDCK-MRP2 variants were grown in the PURPOSE: Sporadic case reports have linked fluoroquinolone antibiotics presence of these drugs, and their viability measured using MTT [3-(4,5- (FQAs), in particular gatifloxacin, with early-onset hypoglycemia. Most dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide] assay. IC50 values reports were in diabetic patients ≥ 65 years old who also received sulfonylurea for each drug combination were estimated by fitting the data to a Hill therapy. We conducted a prospective cohort study to examine the rate of equation using the University of Southern California Laboratory of Applied hypoglycemia associated with gatifloxacin in elderly patients. Pharmacokinetics USC*PACK software. METHODS: Patients ≥ 65 years old admitted to an urban, tertiary-care RESULTS: The IC50 values after 24 hours of exposure to TFV, RTV, LPV, alone teaching hospital and initiated on antibiotic therapy were screened for were ~1000, 130, and 130 µg/ml, respectively. When TFV 10 µg/ml was eligibility. Patients were excluded if they were admitted to the ICU, received combined with either RTV or LPV, the estimated IC50 values were both any antibiotics within the preceding 48 hours or received FQAs other than approximately 100 µg/ml. However, when TFV was combined with MK571 gatifloxacin. Eligibile patients receiving gatifloxacin were enrolled in the FQA and CSA, IC50 values could not be estimated. Similarly, when MDCK-MRP2 cohort, while those receiving non-FQAs served as the control cohort. The was treated with combinations of TFV plus MRP2 inhibitors, IC50 values primary outcome was the rate of hypoglycemia defined as a blood glucose could not be estimated after 24 hours of treatment exposure. level ≤ 60 mg/dl within 48 h after the first dose of antibiotic. CONCLUSION: In the presence of TFV, inhibition of MRP2 inversely RESULTS: Of the patients in the FQA cohort, 22 of 77 (29%) were diabetic, correlates with MDCK proliferation. However, MDCK-MRP2 cells are compared with 41 of 119 (34%) in the control cohort (p=0.48). resistant to TFV plus MRP2 inhibitors even at the highest concentrations, Hypoglycemia occurred in 10 of 77 (13%) patients receiving gatifloxacin as suggesting overexpression of MRP2 may reduce TFV accumulation. This compared to 1 of 119 (0.8%) patients receiving non-FQAs (p=0.001). In the study suggests the role of MRP2 inhibition in TFV-associated renal dysfunction. FQA cohort, hypoglycemia developed in 7 of 22 (32%) diabetic patients Presented at the 6th International Workshop on Clinical Pharmacology of compared with 3 of 55 non-diabetics (5%), yielding a relative risk of 5.8 (95% HIV Therapy, Quebec, Canada, April 28-30, 2005. CI 1.7–20.5, p=0.006). Of the 11 total patients who developed hypoglycemia, 8 were diabetic with 5 receiving sulfonylurea therapy. CONCLUSION: This small, prospective cohort study supports the 5. Retrospective analysis of adverse drug reactions in pediatrics over a 10- relationship between gatifloxacin therapy and the development of year period. Jennifer Le, Pharm.D.1, Thuy Nguyen, Pharm.D.1, Anandi V. Law, hypoglycemia within 48 h of the initial dose in patients ≥ 65 years old, Ph.D.1, Jane Hodding, Pharm.D.2; (1)Western University of Health Sciences, especially if they have diabetes. Concomitant administration of oral Pomona, CA; (2)Miller Children’s Hospital, Long Beach, CA. ACCP ANNUAL MEETING 1433 PURPOSE: Considering the impact of adverse drug reactions (ADR) on post-dosing (Days 1 and 8) for assay of SIM and its active metabolite SIM acid. morbidity and mortality, and the vulnerability of children to experience ADR, RESULTS: Compared with SIM alone, coadministration of CLA and SIM this study was designed to evaluate: 1) the incidence and common types of significantly increased both peak plasma concentration and area under the ADR with respect to severity level in hospitalized children, 2) frequency of concentration–time curve for SIM by approximately 8-fold (p<0.0001).