A Patient-Centered Prescription Drug Label to Promote Appropriate Medication Use and Adherence.

BACKGROUND: Patient misunderstanding of prescription drug label instructions is a common cause of unintentional misuse of medication and adverse health outcomes. Those with limited literacy and English proficiency are at greater risk. OBJECTIVE: To test the effectiveness of a patient-centered drug label strategy, including a Universal Medication Schedule (UMS), to improve proper regimen use and adherence compared to a current standard. DESIGN: Two-arm, multi-site patient-randomized pragmatic trial. PARTICIPANTS: English- and Spanish-speaking patients from eight community health centers in northern Virginia who received prescriptions from a central-fill pharmacy and who were 1) ≥30 years of age, 2) diagnosed with type 2 diabetes and/or hypertension, and 3) taking ≥2 oral medications. INTERVENTION: A patient-centered label (PCL) strategy that incorporated evidence-based practices for format and content, including prioritized information, larger font size, and increased white space. Most notably, instructions were conveyed with the UMS, which uses standard intervals for expressing when to take medicine (morning, noon, evening, bedtime). MAIN MEASURES: Demonstrated proper use of a multi-drug regimen; medication adherence measured by self-report and pill count at 3 and 9 months. KEY RESULTS: A total of 845 patients participated in the study (85.6 % cooperation rate). Patients receiving the PCL demonstrated slightly better proper use of their drug regimens at first exposure (76.9 % vs. 70.1 %, p = 0.06) and at 9 months (85.9 % vs. 77.4 %, p = 0.03). The effect of the PCL was significant for English-speaking patients (OR 2.21, 95 % CI 1.13-4.31) but not for Spanish speakers (OR 1.19, 95 % CI 0.63-2.24). Overall, the intervention did not improve medication adherence. However, significant benefits from the PCL were found among patients with limited literacy (OR 5.08, 95 % CI 1.15-22.37) and for those with medications to be taken ≥2 times a day (OR 2.77, 95 % CI 1.17-6.53). CONCLUSIONS: A simple modification to pharmacy-generated labeling, with minimal investment required, can offer modest improvements to regimen use and adherence, mostly among patients with limited literacy and more complex regimens. Trial Registration (ClinicalTrials.gov): NCT00973180, NCT01200849.

Comparative analysis of outcome measures used in examining neurodevelopmental effects of early childhood anesthesia exposure.

INTRODUCTION: Immature animals exposed to anesthesia display apoptotic neurodegeneration and neurobehavioral deficits. The safety of anesthetic agents in children has been evaluated using a variety of neurodevelopmental outcome measures with varied results. METHODS: The authors used data from the Western Australian Pregnancy Cohort (Raine) Study to examine the association between exposure to anesthesia in children younger than 3 yr of age and three types of outcomes at age of 10 yr: neuropsychological testing, International Classification of Diseases, 9th Revision, Clinical Modification-coded clinical disorders, and academic achievement. The authors' primary analysis was restricted to children with data for all outcomes and covariates from the total cohort of 2,868 children born from 1989 to 1992. The authors used a modified multivariable Poisson regression model to determine the adjusted association of anesthesia exposure with outcomes. RESULTS: Of 781 children studied, 112 had anesthesia exposure. The incidence of deficit ranged from 5.1 to 7.8% in neuropsychological tests, 14.6 to 29.5% in International Classification of Diseases, 9th Revision, Clinical Modification-coded outcomes, and 4.2 to 11.8% in academic achievement tests. Compared with unexposed peers, exposed children had an increased risk of deficit in neuropsychological language assessments (Clinical Evaluation of Language Fundamentals Total Score: adjusted risk ratio, 2.47; 95% CI, 1.41 to 4.33, Clinical Evaluation of Language Fundamentals Receptive Language Score: adjusted risk ratio, 2.23; 95% CI, 1.19 to 4.18, and Clinical Evaluation of Language Fundamentals Expressive Language Score: adjusted risk ratio, 2.00; 95% CI, 1.08 to 3.68) and International Classification of Diseases, 9th Revision, Clinical Modification-coded language and cognitive disorders (adjusted risk ratio, 1.57; 95% CI, 1.18 to 2.10), but not academic achievement scores. CONCLUSIONS: When assessing cognition in children with early exposure to anesthesia, the results may depend on the outcome measure used. Neuropsychological and International Classification of Diseases, 9th Revision, Clinical Modification-coded clinical outcomes showed an increased risk of deficit in exposed children compared with that in unexposed children, whereas academic achievement scores did not. This may explain some of the variation in the literature and underscores the importance of the outcome measures when interpreting studies of cognitive function.

Variation in the α(2A) adrenoceptor gene and the effect of dexmedetomidine on plasma insulin and glucose.

OBJECTIVES: Sympathetic activation inhibits insulin secretion through activation of pancreatic α(2)A adrenoreceptors (α(2A)ARs). A common genetic α(2A)AR variant (rs553668) is associated with impaired insulin secretion. α(2A)R agonists would be expected to decrease insulin secretion, but their effects on glucose homeostasis in humans are poorly characterized. We examined the hypotheses that the selective α(2A)R agonist, dexmedetomidine, decreases plasma insulin levels and increases plasma glucose levels in humans and that these effects are modified by genetic α(2A)AR variants. METHODS: Healthy, fasting, White (n=31) and Black (n=33) participants aged between 18 and 45 years received three sequential infusions of placebo (normal saline) at 30-min intervals, followed by three infusions of dexmedetomidine (0.1, 0.15, and 0.15 mcg/kg). Plasma insulin and glucose concentrations were measured at baseline and after the administration of placebo and dexmedetomidine. We genotyped ADRA2A rs553668 and rs2484516, which characterize haplotypes 4 and 4b, respectively. RESULTS: Dexmedetomidine decreased fasting insulin concentrations by 37%, from a median value after placebo administration of 7.9 µU/ml (interquartile range: 6.0-12.6) to 4.9 µU/ml (interquartile range: 3.5-7.9; P<0.001). Plasma glucose concentrations increased from 76±6 to 79±7 mg/dl (P<0.001). The rs2484516 variant allele was associated with higher baseline insulin concentrations before (P=0.001) and after adjustment for potential confounders (P=0.014) and a greater decrease in insulin concentration after dexmedetomidine administration (P=0.016), which was no longer significant after adjustment for baseline concentrations and other confounders (P=0.58). CONCLUSION: Low-dose dexmedetomidine decreased plasma insulin concentration and mildly increased plasma glucose concentration in healthy fasting individuals. The ADRA2A genetic variation may affect baseline insulin concentrations and thus the insulin decrease after dexmedetomidine administration.

Catecholamine pathway gene variation is associated with norepinephrine and epinephrine concentrations at rest and after exercise.

OBJECTIVE: To examine the hypothesis that genetic variation in enzymes and transporters associated with synthesis, storage, release, and metabolism of catecholamines contributes to the interindividual variability in plasma catecholamine concentrations at rest and after exercise. METHODS: We measured plasma norepinephrine (NE) and epinephrine concentrations at rest and after a standardized exercise protocol in 165 healthy individuals (60% White, 40% African-American) and examined 29 functional or common variants in 14 genes involved in synthesis, transport, or metabolism of catecholamines. We examined the relationship between genotypes and NE concentrations at rest and the increase after exercise (ΔNE) by multiple linear regression with adjustment for covariates [age, race, sex, BMI, fitness, and resting NE (for ΔNE)]. As a secondary outcome, we carried out similar analyses for epinephrine concentrations. RESULTS: There was large interindividual variability in resting NE (mean, 204±102 pg/ml; range, 39-616 pg/ml) and ΔNE (mean, 256±206 pg/ml; range, -97 to 953 pg/ml). Resting NE was significantly associated with variants of four genes: CYB561 (P<0.001), VMAT2 (P=0.016), CHGA (P=0.039), and PNMT (P=0.038). ΔNE after exercise was associated with three variants of PNMT (P=0.041) and COMT (P=0.033 and 0.035), and resting and exercise epinephrine concentrations were associated with two variants each. CONCLUSION: The findings of this exploratory study suggest that variation in catecholamine pathway genes contributes to the interindividual variability in plasma NE and epinephrine concentrations at rest and after exercise.

The tryptophan hydroxylase inhibitor LX1031 shows clinical benefit in patients with nonconstipating irritable bowel syndrome.

BACKGROUND & AIMS: Serotonin (5-hydroxytryptamine [5-HT]) has an important role in gastrointestinal function. LX1031 is an oral, locally acting, small molecule inhibitor of tryptophan hydroxylase (TPH). Local inhibition of TPH in the gastrointestinal tract might reduce mucosal production of serotonin (5-HT) and be used to treat patients with nonconstipating irritable bowel syndrome (IBS). METHODS: We evaluated 2 dose levels of LX1031 (250 mg or 1000 mg, given 4 times/day) in a 28-day, multicenter, randomized, double-blind, placebo-controlled study of 155 patients with nonconstipating IBS. 5-hydroxyindoleacetic acid (5-HIAA), a biomarker of pharmacodynamic activity, was measured in urine samples at baseline (24 hours after LX1031 administration), and at weeks 4 and 6 (n = 76). RESULTS: Each dose of LX1031 was safe and well-tolerated. The primary efficacy end point, relief of IBS pain and discomfort, improved significantly in patients given 1000 mg LX1031 (25.5%), compared with those given placebo, at week 1 (P = .018); with nonsignificant improvements at weeks 2, 3, and 4 (17.9%, 16.3%, and 11.6%, respectively). Symptom improvement correlated with a dose-dependent reduction in 5-HIAA, a marker for TPH inhibition, from baseline until week 4. This suggests the efficacy of LX1031 is related to the extent of inhibition of 5-HT biosynthesis. Stool consistency significantly improved, compared with the group given placebo, at weeks 1 and 4 (P < .01) and at week 2 (P < .001). CONCLUSIONS: In a phase 2 study, LX1031 was well tolerated, relieving symptoms and increasing stool consistency in patients with nonconstipating IBS. Symptom relief was associated with reduced levels of 5-HIAA in urine samples. This marker might be used to identify patients with nonconstipating IBS who respond to inhibitors of 5-HT synthesis.

CYP2A6 genetic variation and dexmedetomidine disposition.

PURPOSE: There is a large interindividual variability in dexmedetomidine dose requirements for sedation of patients in intensive care units (ICU). Cytochrome P450 2A6 (CYP2A6) mediates an important route of dexmedetomidine metabolism, and genetic variation in CYP2A6 affects the clearance of other substrate drugs. We examined whether CYP2A6 genotypes affect dexmedetomidine disposition. METHODS: In 43 critically ill ICU patients receiving dexmedetomidine infusions adjusted to achieve the desired level of sedation, we determined a median of five plasma dexmedetomidine concentrations each. Forty subjects were genotyped for five common CYP2A6 alleles and grouped into normal (n = 33), intermediate (n = 5), and slow metabolizers (n = 2). RESULTS: Using a Bayesian hierarchical nonlinear mixture model, estimated dexmedetomidine clearance was 49.1 L/h (posterior mean; 95% credible interval 41.4-57.6 L/h). There were no significant differences in dexmedetomidine clearance among normal, intermediate, and slow CYP2A6 metabolizer groups. CONCLUSION: Genetic variation in CYP2A6 does not appear to be an important determinant of dexmedetomidine clearance in ICU patients.

Effect of standardized, patient-centered label instructions to improve comprehension of prescription drug use.

OBJECTIVE: To evaluate the effectiveness of standardized, patient-centered label (PCL) instructions to improve comprehension of prescription drug use compared with typical instructions. METHODS: A total of 500 adult patients recruited from 2 academic and 2 community primary care clinics in Chicago, IL and Shreveport, LA were assigned to receive as follows: (1) standard prescription instructions written as times per day (once, twice 3 times per day) (usual care), (2) PCL instructions that specify explicit timing with standard intervals (morning, noon, evening, bedtime) (PCL), or (3) PCL instructions with a graphic aid to visually depict dose and timing of the medication (PCL + Graphic). The outcome was correct interpretation of label instructions. RESULTS: Instructions with the PCL format were more likely to be correctly interpreted compared with standard instructions (adjusted relative risk [RR]: 1.33, 95% confidence interval [CI]: 1.25-1.41). Inclusion of the graphic aid (PCL + Graphic) decreased rates of correct interpretation compared with PCL instructions alone (RR: 0.93; 95% CI: 0.89-0.97). Patients with low literacy were better able to interpret PCL instructions (low literacy: RR: 1.39; 95% CI: 1.14-1.68; P = 0.001). CONCLUSION: The PCL approach could improve patients' understanding and use of their medication regimen.

The alpha2C-adrenoceptor deletion322-325 variant and cold-induced vasoconstriction.

OBJECTIVES: Cold-induced vasoconstriction is mediated in part by selective enhancement of local alpha(2C)-adrenoceptor (alpha(2C)-AR) activity. A common insertion-deletion variant in the alpha(2C)-AR gene (ADRA2C del322-325) results in an approximately 85% reduction of agonist-mediated function in vitro. We tested the hypothesis that individuals with the ADRA2C del322-325 variant have attenuated vasoconstriction in response to cold. METHODS: Cutaneous digital blood flow (flux) was measured by laser Doppler flowmetry in a controlled environment at room temperature and during two cycles of graduated local heat and cold exposure in 31 subjects. Temperature-response curves were analyzed to estimate the following measures: E(min) (minimal flux during cooling), and ET(50) and ET(90) (the local temperature at which flux decreased by 50 and 90%, respectively). RESULTS: We found no significant genotypic differences in E(min) (24.3 +/- 19.5, 30.0 +/- 20.5, and 21.5 +/- 25.9 AU for ins/ins, ins/del, and del/del genotypes, respectively; P = 0.48), ET(50) (25.5 +/- 6.0, 25.1 +/- 6.7, and 25.1 +/- 7.1 degrees C; P = 0.99), or ET(90) (20.5 +/- 4.7, 22.1 +/- 4.0, and 20.8 +/- 6.7 degrees C; P = 0.77) in either the first or second heating and cooling cycle (cycle 1 values presented). INTERPRETATION: The ADRA2C del322-325 variant did not affect vascular sensitivity to local cold exposure.

Rationale and design of the regimen education and messaging in diabetes (REMinD) trial.

BACKGROUND: Individuals with type 2 diabetes manage complex multi-drug regimens, but nearly half of all patients do not consistently take the dose prescribed for them, and therefore may not receive the full potential therapeutic benefit. Both patient and health system factors contribute to achieving and maintaining medication adherence. To determine if patients with type 2 diabetes who are concurrently managing other chronic conditions could improve their adherence, we devised and are testing a multifaceted, primary care-based strategy to provide health literacy-appropriate and language concordant regimen information, guidance and reminders. OBJECTIVE: We are testing the effectiveness of an electronic health record (EHR) based strategy and short message service (SMS) text reminders to help patients with type 2 diabetes adhere to their medications. METHODS: We are conducting a 3-arm, multi-site trial to test and compare the effectiveness of the EHR, and EHR + SMS text reminder strategies compared to usual care on medication adherence. Our goal is to enroll a total of 900 English or Spanish-speaking patients with type 2 diabetes and hemoglobin A1C value ≥7.5%. Enrolled participants will complete interviews at baseline and 3 and 6 months following their baseline interview. CONCLUSIONS: Our trial is evaluating practical, clinic-based, scalable, evidence-based solutions for patients with type 2 diabetes managing complex medication regimens. Our findings will evaluate strategies that can be implemented broadly in primary care practices, and programmed as defaults within EHRs to support appropriate medication adherence to allow the widespread implementation of those strategies.

Tariquidar, a selective P-glycoprotein inhibitor, does not potentiate loperamide's opioid brain effects in humans despite full inhibition of lymphocyte P-glycoprotein.

BACKGROUND: Loperamide, a potent opioid, has been used as an in vivo probe to assess P-glycoprotein activity at the blood-brain barrier, because P-glycoprotein inhibition allows loperamide to cross the blood-brain barrier and exert its central opioid effects. In humans, studies with nonselective and moderately potent inhibitors resulted in mild opioid effects but were confounded by the concurrent inhibition of loperamide's metabolism. The authors studied the effect of the highly selective, potent P-glycoprotein inhibitor tariquidar on loperamide's central opioid effects. METHODS: In a randomized, double-blind, crossover study, nine healthy subjects received on 2 study days oral loperamide (32 mg) followed by an intravenous infusion of either tariquidar (150 mg) or placebo. Central opioid effects (pupil diameter, sedation) were measured for 12 h, and blood samples were drawn up to 48 h after drug administration to determine plasma loperamide concentrations and ex vivo P-glycoprotein activity in T lymphocytes. Values for pupil diameter and loperamide concentrations were plotted over time, and the areas under the curves on the tariquidar and placebo study day were compared within each subject. RESULTS: Tariquidar did not significantly affect loperamide's central effects (median reduction in pupil diameter area under the curve, 6.9% [interquartile range, -1.4 to 12.1%]; P = 0.11) or plasma loperamide concentrations (P = 0.12) but profoundly inhibited P-glycoprotein in lymphocytes by 93.7% (95% confidence interval, 92.0-95.3%). CONCLUSION: These results suggest that despite full inhibition of lymphocyte P-glycoprotein, the selective P-glycoprotein inhibitor tariquidar does not potentiate loperamide's opioid brain effects in humans.

Effect of the alpha2C-adrenoreceptor deletion322-325 variant on sympathetic activity and cardiovascular measures in healthy subjects.

BACKGROUND: The alpha2C-adrenergic receptor plays an important role in the regulation of the sympathetic nervous system and, therefore, blood pressure and heart rate. A deletion polymorphism in its gene (ADRA2C del322-325), ten times more common in black than white Americans, has been associated with a loss of function in vitro and, under controlled study conditions, raised blood pressure and catecholamine secretion. We therefore examined the hypothesis that the ADRA2C deletion variant would alter sympathetic activity and contribute to ethnic differences in blood pressure. METHODS: We measured resting plasma norepinephrine and epinephrine concentrations, blood pressure and heart rate in 224 healthy subjects (127 whites), and determined their ADRA2C del322-325 genotype. Additionally, we analyzed heart rate variability (HRV) in a subgroup of 50 black subjects. RESULTS: Systolic (SBP) and diastolic blood pressure (DBP) were higher in blacks than whites [difference (95% confidence interval), 4.4 (1.5-7.4) mmHg, P = 0.003; and 2.7 (0.7-4.6) mmHg, P = 0.01, respectively]. Norepinephrine concentrations did not differ among subjects with 0, 1 and 2 copies of the deletion variant [median (interquartile range), 185.0 (147.5-269.8), 200.0 (154.9-257.0) and 173.8 (158.5-235.8) pg/ml, respectively; P = 0.54]. Similarly, none of the HRV parameters differed among the genotype groups. In multiple linear regression analyses adjusting for multiple covariates, the deletion genotype was not associated with SBP or DBP. In contrast, black ethnicity was associated with higher SBP (P = 0.001) and DBP (P = 0.005). CONCLUSION: The ADRA2C deletion polymorphism had no effect on markers of resting sympathetic activity and cardiovascular measures, and did not account for ethnic differences in blood pressure.

Development and rationale for a multifactorial, randomized controlled trial to test strategies to promote adherence to complex drug regimens among older adults.

BACKGROUND: Patients with chronic conditions are often responsible for self-managing complex, multi-drug regimens with minimal professional clinical support. While numerous interventions to promote and support medication adherence have been tested, most have had limited success or have been too resource-intensive for real-world implementation. OBJECTIVE: To compare the effectiveness of multiple low-cost, technology-enabled strategies, alone and in combination, for promoting medication regimen adherence among older adults. METHODS: Older, English or Spanish-speaking patients on complex drug regimens (N=1505) will be recruited from a community health system in Chicago, IL. Enrolled patients will be randomized to one of four study arms, receiving either: 1) enhanced usual care alone; 2) daily medication reminders via SMS text messages; 3) medication monitoring via a patient portal-based assessment; or 4) both SMS text message reminders and portal-based medication monitoring. The primary outcome of the study is medication adherence, which will be assessed via multiple measures at baseline, 2months, and 6months. The effect of intervention strategies on clinical markers (hemoglobin A1c, blood pressure, cholesterol level), as well as intervention fidelity and the barriers and costs of implementation will also be evaluated. CONCLUSIONS: This randomized controlled trial will evaluate the impact of various low-cost intervention strategies on adherence to complex medication regimens and will explore barriers to implementation. If the studied intervention strategies are shown to be effective, then these approaches could be effectively deployed across a diverse range of clinical settings and patient populations. CLINICAL TRIAL REGISTRATION: This trial is registered on clinicaltrials.govNCT02820753.

The erythromycin breath test reflects P-glycoprotein function independently of cytochrome P450 3A activity.

BACKGROUND: The erythromycin breath test (ERBT) has been widely used as a phenotypic measure of cytochrome P450 (CYP) 3A activity in individuals, as well as its modulation by inhibitors or inducers. However, it is not entirely clear what this measure actually reflects because, in addition to CYP3A, animal studies suggest that P-glycoprotein is also involved in erythromycin's hepatic disposition. Thus studies were undertaken to determine the effect of tariquidar, a potent P-glycoprotein inhibitor that does not affect CYP3A activity, on the ERBT and on the CYP3A-mediated metabolism of midazolam, a non-P-glycoprotein substrate. METHODS: A randomized, double-blind, 2-way crossover trial was performed in 8 healthy subjects involving the intravenous administration of either placebo or tariquidar (150 mg over a period of 30 minutes) on 2 study days 2 weeks apart. On both days, a 1-hour ERBT was performed, followed by determination of midazolam's systemic clearance after a 1-mg intravenous dose. RESULTS: Tariquidar increased the ERBT 1-hour value in all subjects (median, 2.1% [interquartile range (IQR), 1.9% to 3.3%] versus 5.4% [IQR, 3.7% to 7.8%] for placebo and tariquidar, respectively; P = .012), representing a median 2.3-fold (IQR, 1.9- to 3.0-fold) increase. By contrast, midazolam's systemic clearance after tariquidar was unchanged (median change, -4.6% [IQR, -10.2% to 10.7%]; P = .78). CONCLUSIONS: Hepatic P-glycoprotein is an important determinant of the ERBT and a potentially confounding factor in interpreting the meaning of the trait measure. In addition, the results demonstrate the dynamic interplay between hepatic drug metabolism and transport of dual CYP3A/P-glycoprotein substrates.