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Amber L Beitelshees

Publications and source records attributed to Amber L Beitelshees.

11 recordsLinked to original sources
PubMed2026

2025 Acute Coronary Syndrome Guideline: Missing the Boat on CYP2C19 Genotyping.

The 2025 American College of Cardiology/American Heart Association/American College of Emergency Physicians/National Association of Emergency Medical Services Physicians/Society for Cardiovascular Angiography & Interventions acute coronary syndrome guideline focuses on strategies to reduce bleeding risk with antiplatelet therapy yet lacks any recommendation related to CYP2C19 genotyping. The impact of CYP2C19 loss-of-function alleles on the effectiveness of clopidogrel is well documented, and although prasugrel and ticagrelor more effectively reduce the risk for atherothrombotic events compared with clopidogrel in patients with a CYP2C19 loss-of-function allele, clopidogrel reduces bleeding risk without an increase in atherothrombotic events compared with prasugrel or ticagrelor in those without a loss-of-function allele. Accordingly, an American Heart Association Scientific Statement supports CYP2C19 genetic testing before oral P2Y12 inhibitors are prescribed. This commentary summarizes the evidence in support of CYP2C19-guided P2Y12 inhibitor selection in the context of other 2025 acute coronary syndrome guideline recommendations and urges future guidelines to incorporate recommendations for CYP2C19 genotyping, especially for those at high bleeding risk.

Humans↗
PubMed2025

Impact of Race on Profiles of Platelet Reactivity and Clinical Outcomes in Clopidogrel-Treated Participants.

Black individuals undergoing percutaneous coronary intervention (PCI) experience higher rates of major adverse cardiovascular events (MACE) than non-Black individuals. This study assessed the racial differences in platelet reactivity and clinical outcomes among clopidogrel-treated participants. Two cohorts were analyzed. The pharmacodynamic (PD) cohort involved patients with atherosclerotic cardiovascular disease on maintenance clopidogrel therapy undergoing platelet function testing. The primary outcome was high platelet reactivity (HPR, i.e., P2Y12 reaction unit [PRU]&#x2009;>&#x2009;208). The PCI cohort included participants undergoing PCI on clopidogrel-based dual antiplatelet therapy. The primary outcome was 1-year MACE, defined as the composite of cardiovascular death, myocardial infarction (MI), ischemic stroke, or stent thrombosis. Data on clinically significant bleeding and CYP2C19 genotyping alleles were collected. The PD and PCI cohorts included 728 (32.1% Black) and 2,770 (20.5% Black) participants, respectively. Black participants had higher PRU levels (184 [IQR 128-234] vs. 144 [IQR 88-195]; P&#x2009;<&#x2009;0.001) and higher prevalence of HPR (39.3% vs. 20.6%; P&#x2009;<&#x2009;0.001). Independent predictors of HPR included Black race, hemoglobin levels, and presence of CYP2C19 loss-of-function allele. In the PCI cohort, Black participants had a higher risk of MACE (HR 1.47; 95% CI 1.02-2.11; P&#x2009;=&#x2009;0.037), primarily driven by MI (HR 1.71; 95% CI 1.09-2.67; P&#x2009;=&#x2009;0.019), with no significant difference in clinically significant bleeding (HR 1.08; 95% CI 0.65-1.80; P&#x2009;=&#x2009;0.768). Black participants on clopidogrel exhibit higher platelet reactivity, increased rates of HPR, and an elevated risk of MACE within 1 year after PCI, without significant differences in bleeding compared to non-Black participants.

Aged↗
PubMed2006

Common laboratory methods in pharmacogenomics studies.

PURPOSE: Common laboratory methods used in pharmacogenomics studies are described. SUMMARY: The reliable and accurate determination of a person's genetic makeup at a particular locus in the DNA molecule, or genotype, is fundamental to pharmacogenomics. Whole blood cells and buccal cells are commonly collected to obtain a DNA sample. Once DNA is collected, the genomic DNA must be isolated from other cellular material. Next, a specific region of interest must be identified and amplified, performed via polymerase chain reaction (PCR). Gel electrophoresis is often performed after PCR to verify that PCR was successful and that the amplified target sequence is the correct size. Numerous methods are available to determine a person's genotype and differ based on allele discrimination and detection. PCR coupled with restriction fragment length polymorphism (RFLP) analysis, a conventional genotyping method, does not rely on automated technology and is practical for laboratories that genotype a limited number of samples. Pyrosequencing is an automated genotyping method in which the principal allele discrimination method is a primer extension reaction coupled with a luciferase-based enzyme reaction. TaqMan relies on the use of fluorescencelabeled probes, in addition to PCR primers, in the reaction mixture, enabling PCR amplification and allele discrimination in the same step. Mass spectrometry differentiates DNA molecules using a defined mass. Denaturing high-performance liquid chromatography (DHPLC) uses a reverse-phase ion-pair column to discriminate between variant and nonvariant alleles. CONCLUSION: An understanding of the common genotyping methods used in pharmacogenomics studies, including PCR-RFLP analysis, pyrosequencing, TaqMan, mass spectrometry, and DHPLC, will aid pharmacy practitioners and students when interpreting the methods sections of such studies.

Clinical Laboratory Techniques↗
PubMed2006

Applying pharmacogenomics to enhance the use of biomarkers for drug effect and drug safety.

Pharmacogenomics is used to improve patient outcome by maximizing the likelihood of desired effects and minimizing the risk of adverse events using an individual's genetic profile. As such, pharmacogenomics can be used to improve current risk-management strategies (improving the risk-benefit balance). Two areas of great promise for pharmacogenomics in this regard are emerging: (i) the pharmacogenomics of modulating disease biomarkers (to provide insight into novel mechanisms of drug response and to identify the patients most likely to respond to a drug in a favorable way); and (ii) using pharmacogenomics to enhance drug safety. Given that novel biomarkers could enable the earlier detection of many diseases and more-widespread therapies for primary prevention, pharmacogenomics provides the opportunity to identify the patients most likely to respond to these therapies, thereby preserving valuable health-care resources. The use of pharmacogenomics in pharmacovigilance could also be useful for risk-stratifying patients and for helping to identify the mechanisms involved in adverse events.

5-Lipoxygenase-Activating Proteins↗
PubMed2006

CXCL5 gene polymorphisms are related to systemic concentrations and leukocyte production of epithelial neutrophil-activating peptide (ENA-78).

Data exist linking elevated epithelial neutrophil activating peptide (ENA-78) concentrations with myriad inflammatory conditions. ENA-78 is encoded by the CXCL5 gene which has recently been shown to be polymorphic in nature (rs352046 and rs425535). No functional data on these polymorphisms exist. We investigated whether CXCL5 polymorphisms are associated with differences in plasma ENA-78 concentrations or leukocyte production of ENA-78 from cultured leukocytes in relatively healthy adults. We genotyped 114 adults for the above polymorphisms. Variant alleles at both loci were highly linked (D'=1, r2=0.94). The rs352046 variant allele was associated with significantly higher ENA-78 plasma concentrations. A genotype effect was also demonstrated for this polymorphism and leukocyte production of ENA-78. Both polymorphisms were predicted to have functional consequences by in silico analyses, with the rs352046 polymorphism found to occur at a transcription factor binding site for myeloid zinc finger proteins and the rs425535 polymorphism found to be located in an exon splicing enhancer site. Our findings add to the strength of CXCL5 as candidate gene in future disease-gene and pharmacogenetic association studies.

Adult↗
PubMed2006

Discordance between availability of pharmacogenetics studies and pharmacogenetics-based prescribing information for the top 200 drugs.

BACKGROUND: Despite growing numbers of pharmacogenetics studies, little pharmacogenetics-based prescribing information is available to practitioners. It is possible that the lack of prescribing data for commonly used drugs is due to a paucity of evidence-based pharmacogenetics literature for these agents. OBJECTIVE: To investigate the relationship between pharmacogenetics prescribing data in drug package inserts (PIs) and pharmacogenetics research literature for agents represented in the top 200 prescribed drugs for 2003. METHODS: A PubMed search (to August 7, 2004) was performed to identify pharmacogenetics studies relevant to the top 200 drugs. These data were compared with PIs for drugs in the top 200 list that contained pharmacogenetics prescribing information. RESULTS: Pharmacogenetics data in the literature were available for 71.3% of the top 200 drugs. The gene involved coded for a drug-metabolizing enzyme in 34.5% of the literature sampled. The remaining 65.5% of the pharmacogenetics studies contained information largely related to genetic variability in target proteins and drug transporters. Three drugs with PIs containing pharmacogenetics prescribing information deemed to be useful to guide therapy were in the top 200 list (celecoxib, fluoxetine, pantoprazole). There was no consensus on the strength of association between genetic variability and drug response for these agents. CONCLUSIONS: The lack of specific pharmacogenetics-based prescribing information in PIs for commonly used drugs does not seem to be related to a paucity of pharmacogenetics data in the research literature. Rather, other factors including, but not limited to, the uncertain clinical relevance of genetic associations may make practical prescribing recommendations difficult.

Drug Prescriptions↗
PubMed2006

Discordant beta-blocker effects on clinic, ambulatory, resting, and exercise hemodynamics in patients with hypertension.

STUDY OBJECTIVES: To determine the correlation between ambulatory and clinic blood pressure in assessing antihypertensive response to beta-blockade, to test whether blood pressure response to metoprolol is associated with the heart rate response, and to determine whether exercise and resting heart rate responses to metoprolol are correlated. DESIGN: Post hoc analysis of a prospective cohort study. SETTING: University-affiliated general clinical research center. PATIENTS: Fifty-one patients aged 35-65 years with uncomplicated hypertension. Intervention. All patients received metoprolol at a dosage titrated to achieve a diastolic blood pressure below 90 mm Hg. MEASUREMENTS AND MAIN RESULTS: Clinic and 24-hour ambulatory blood pressure measurements were obtained and exercise treadmill testing was performed before and after metoprolol treatment. Based on ambulatory blood pressure data, 24 patients (47%) responded (defined as at least a 10% reduction in diastolic blood pressure) to metoprolol compared with 36 patients (71%) based on clinic blood pressure data (p=0.027). Clinic blood pressure was associated with a 67% false-positive rate (responsive blood pressure by clinic data that was actually nonresponsive by ambulatory data). Blood pressure responders and nonresponders exhibited similar reductions in exercise heart rate (24% and 23%, p=0.74). However, responses to metoprolol measured by exercise heart rate versus resting heart rate were not significantly correlated (r=0.24, p=0.105). CONCLUSION: Reliance on clinic blood pressure or resting heart rate for making beta-blocker treatment decisions may yield less than optimal assessment of the antihypertensive response or degree of beta-blockade.

Adrenergic beta-Antagonists↗
PubMed2004

Pharmacokinetics and CYP2D6 genotypes do not predict metoprolol adverse events or efficacy in hypertension.

OBJECTIVE: Beta-Blocker use can be associated with adverse effects that may have an impact on adherence or harm patients. The commonly prescribed beta-blocker metoprolol is metabolized by the polymorphic cytochrome P450 (CYP) 2D6 enzyme, resulting in widely variable drug exposure. We investigated whether metoprolol plasma concentrations, CYP2D6 polymorphisms, or genotype-derived phenotype was associated with adverse effects or efficacy in patients with hypertension. METHODS: Fifty hypertensive patients received metoprolol by use of a dose-titration algorithm until target blood pressure was reached, intolerable side effects occurred, or maximal daily dose was achieved. CYP2D6 genotype was determined by methods based on polymerase chain reaction-restriction fragment length polymorphism and included 19 allelic variants. Patients were assigned to standard phenotype groups on the basis of genotype. Patients were also assigned activity scores based on functional activity of the alleles. General and dose-limiting adverse events and blood pressure responses were analyzed in relation to metoprolol steady-state pharmacokinetic profile and CYP2D6 genotype-derived phenotype. RESULTS: Poor metabolizers had a significantly longer elimination half-life, higher S-metoprolol area under the plasma concentration-time curve (AUC), and lower oral clearance (P < or = .007 for all parameters). There was a 29.6-fold variability in AUC among extensive metabolizers, which was largely explained by CYP2D6 activity scores (P = .032 for ordered differences in AUC by activity score among extensive metabolizers). Overall general and dose-limiting adverse event rates were 46% and 14%, respectively. General adverse event rates did not differ by AUC quartile (66.7% [95% confidence interval (CI), 35.4%-88.7%] and 41.7% [95% CI, 16.5%-71.4%] in the lowest and highest quartiles, respectively; P = .09 among all quartiles). Dose-limiting adverse event rates were also not different by AUC quartile (16.7% [95% CI, 2.9%-49.1%] and 8.3% [95% CI, 0.4%-40.2%] in the lowest and highest quartiles; P = .35 among all quartiles). Furthermore, adverse event rates did not differ by activity scores or between extensive, intermediate, or poor metabolizers. Antihypertensive response rate and blood pressure changes also were not influenced by differences in plasma concentrations or CYP2D6 genotypes. CONCLUSIONS: As expected, CYP2D6 genotype-phenotype correlates with differences in metoprolol pharmacokinetics. However, there was no association between variable pharmacokinetics or CYP2D6 genotype and beta-blocker-induced adverse effects or efficacy.

Adrenergic beta-Antagonists↗
PubMed2004

Racial differences in patients' potassium concentrations during spironolactone therapy for heart failure.

STUDY OBJECTIVE: To determine whether the effects of spironolactone on potassium homeostasis vary by race by comparing serum potassium concentrations and potassium supplement use in African-American and Caucasian patients receiving spironolactone for heart failure. DESIGN: Retrospective medical record review. SETTING: Two heart failure centers. PATIENTS: Fifty African-American and 67 Caucasian patients with heart failure who were receiving a stable dosage of spironolactone in addition to standard heart failure therapy with an angiotensin-converting enzyme (ACE) inhibitor or angiotensin receptor blocker. MEASUREMENTS AND MAIN RESULTS: Medical records of eligible patients were reviewed by pharmacists and physicians who specialize in heart failure management. No significant differences were observed in diuretic therapy or renal function between racial groups; however, African-Americans were receiving higher doses of ACE inhibitors. African-Americans had lower serum potassium concentrations (4.2 +/- 0.4 vs 4.5 +/- 0.5 mEq/L, p<0.01) and a higher prevalence of potassium supplementation (48% vs 15%, p<0.01). In a subset of patients, spironolactone therapy was associated with a 2-fold greater increase in serum potassium concentration and a 3-fold greater reduction in potassium supplement use among Caucasians than African-Americans. CONCLUSION: Our findings suggest that a large percentage of patients with heart failure, particularly African-Americans, still require potassium supplementation despite treatment with spironolactone and standard vasodilator therapy.

Adrenergic beta-Antagonists↗