Nine-gene pharmacogenomics profile service: The Mayo Clinic experience.

PURPOSE: The Pharmacogenomics (PGx) Profile Service was a proof-of-concept project to implement PGx in patient care at Mayo Clinic. METHODS: Eighty-two healthy individuals aged 18 and older underwent genotyping of CYP1A2, CYP2C9, CYP2C19, CYP2D6, CYP3A4, CYP3A5, SLCO1B1, HLA-B*58:01, and VKORC1. A PGx pharmacist was involved in ordering, meeting with patients, interpreting, reviewing, and documenting results. RESULTS: Ninety three percent were CYP1A2 rapid metabolizers, 92% CYP3A4 normal metabolizers, and 88% CYP3A5 poor metabolizers; phenotype frequencies for CYP2C19 and CYP2D6 varied. Seventy-three percent had normal functioning SLCO1B1 transporter, 4% carried the HLA-B*58:01 risk variant, and 35% carried VKORC1 and CYP2C9 variants that increased warfarin sensitivity. CONCLUSION: Pre-emptive PGx testing offered medication improvement opportunity in 56% of participants for commonly used medications. A collaborative approach involving a PGx pharmacist integrated within a clinical practice with regards to utility of PGx results allowed for implementation of the PGx Profile Service. KEY POINTS: The Mayo Clinic PGx (PGx) Profile Service was a proof-of-concept project to utilize PGx testing as another clinical tool to enhance medication selection and decrease serious adverse reactions or medication failures. Over one-half of participants in the pilot using the PGx Profile Service were predicted to benefit from pre-emptive PGx testing to guide pharmacotherapy. PGx pharmacists played a crucial role in the PGx Profile Service by educating participants, identifying medication-gene interactions, and providing evidence-based (CPIC and DPWG) PGx recommendations for past, current, and future medication us.

Implementation of preemptive DNA sequence-based pharmacogenomics testing across a large academic medical center: The Mayo-Baylor RIGHT 10K Study.

PURPOSE: The Mayo-Baylor RIGHT 10K Study enabled preemptive, sequence-based pharmacogenomics (PGx)-driven drug prescribing practices in routine clinical care within a large cohort. We also generated the tools and resources necessary for clinical PGx implementation and identified challenges that need to be overcome. Furthermore, we measured the frequency of both common genetic variation for which clinical guidelines already exist and rare variation that could be detected by DNA sequencing, rather than genotyping. METHODS: Targeted oligonucleotide-capture sequencing of 77 pharmacogenes was performed using DNA from 10,077 consented Mayo Clinic Biobank volunteers. The resulting predicted drug response-related phenotypes for 13 genes, including CYP2D6 and HLA, affecting 21 drug-gene pairs, were deposited preemptively in the Mayo electronic health record. RESULTS: For the 13 pharmacogenes of interest, the genomes of 79% of participants carried clinically actionable variants in 3 or more genes, and DNA sequencing identified an average of 3.3 additional conservatively predicted deleterious variants that would not have been evident using genotyping. CONCLUSION: Implementation of preemptive rather than reactive and sequence-based rather than genotype-based PGx prescribing revealed nearly universal patient applicability and required integrated institution-wide resources to fully realize individualized drug therapy and to show more efficient use of health care resources.

Use of convalescent plasma in COVID-19 patients with immunosuppression.

In the absence of effective countermeasures, human convalescent plasma has been widely used to treat severe acute respiratory syndrome coronavirus 2, the causative agent of novel coronavirus disease 19 (COVID-19), including among patients with innate or acquired immunosuppression. However, the association between COVID-19-associated mortality in patients with immunosuppression and therapeutic use of convalescent plasma is unknown. We review 75 reports, including one large matched-control registry study of 143 COVID-19 patients with hematological malignancies, and 51 case reports and 23 case series representing 238 COVID-19 patients with immunosuppression. We review clinical features and treatment protocols of COVID-19 patients with immunosuppression after treatment with human convalescent plasma. We also discuss the time course and clinical features of recovery. The available data from case reports and case series provide evidence suggesting a mortality benefit and rapid clinical improvement in patients with several forms of immunosuppression following COVID-19 convalescent plasma transfusion. The utility of convalescent plasma or other forms of antibody therapy in immune-deficient and immune-suppressed patients with COVID-19 warrants further investigation.

Description of Pharmacogenomic Testing Among Patients Admitted to the Intensive Care Unit After Cardiovascular Surgery.

BACKGROUND: Pharmacogenomic (PGx) testing has the potential to provide information on specific drug-metabolizing enzymes that may lead to an absence, reduction, or increase in medication effect in patients. There is a paucity of prospective studies examining PGx testing in the intensive care unit (ICU) setting. RESEARCH AIMS: To (1) obtain a PGx panel in a sample of cardiovascular (CV) surgical patients with a planned ICU stay and identify phenotypes, and (2) identify PGx variants that may inform treatment regimens and may warrant prescribing adjustments. DESIGN AND METHODS: Descriptive, single cohort cross-sectional design. Adult (≥18 years) CV patients with an anticipated postoperative ICU stay were enrolled from a large Midwestern tertiary academic medical center. Eligible patients provided informed consent at the time of their CV clinic appointment; PGx testing was then ordered. Pharmacogenomic testing consisted of the Focused Pharmacogenomics panel which included 10 genes and 55 medications. RESULTS: Of the 272 patients screened, 100 (68% male) patients completed PGx testing (mean age 66.2 ± 9.6 years, mean Acute Physiology, Age and Chronic Health Evaluation III score 76.1 ± standard deviation). Pharmacogenomic results were available in the medical record within a median of 52.4 hours (interquartile range: 33.4-80.3). Pharmacogenomic testing results identified 5 CYP2C19 poor metabolizers, 26 CYP2C19 rapid metabolizers, 5 CYP2C19 ultrarapid metabolizers, 6 CYP2D6 poor metabolizers, 5 CYP2D6 poor to intermediate metabolizers, and 2 CYP2D6 rapid metabolizers identified. Overall, 98% of patients had actionable or potentially actionable PGx results, including 82% for warfarin, 65% for propafenone, 65% for tramadol, 46% for oxycodone, 45% for metoprolol, 33% for clopidogrel, 32% for proton pump inhibitors, 25% for statins, and 12% for haloperidol. CONCLUSIONS: A significant portion of patients had identified genetic variants that may warrant changes in medication management during and after CV-ICU stay. It remains to be seen if PGx testing leads to improvements in ICU patient outcomes.

Assessment of resistance vessel function in human skeletal muscle: guidelines for experimental design, Doppler ultrasound, and pharmacology.

The introduction of duplex Doppler ultrasound almost half a century ago signified a revolutionary advance in the ability to assess limb blood flow in humans. It is now widely used to assess blood flow under a variety of experimental conditions to study skeletal muscle resistance vessel function. Despite its pervasive adoption, there is substantial variability between studies in relation to experimental protocols, procedures for data analysis, and interpretation of findings. This guideline results from a collegial discussion among physiologists and pharmacologists, with the goal of providing general as well as specific recommendations regarding the conduct of human studies involving Doppler ultrasound-based measures of resistance vessel function in skeletal muscle. Indeed, the focus is on methods used to assess resistance vessel function and not upstream conduit artery function (i.e., macrovasculature), which has been expertly reviewed elsewhere. In particular, we address topics related to experimental design, data collection, and signal processing as well as review common procedures used to assess resistance vessel function, including postocclusive reactive hyperemia, passive limb movement, acute single limb exercise, and pharmacological interventions.

Forearm vasodilatation to a ß2 -adrenergic receptor agonist in premenopausal and postmenopausal women.

NEW FINDINGS: What is the central question of this study? What is the role of ß2 -adrenergic receptor (ß2 AR) vasodilatation in older postmenopausal women as compared to premenopausal women and the role of nitric oxide (NO) in ß2 AR-mediated vasodilatation in both groups of women? What is the main finding and its importance? ß2 AR responsiveness is blunted in postmenopausal women compared to young premenopausal women. Additionally, NO may contribute to ß2 AR-mediated vasodilatation in young premenopausal women. ABSTRACT: ß2 -Adrenergic receptor (ß2 AR)-mediated vasodilatation, which is partially dependent on nitric oxide (NO) formation, is blunted in men at risk for developing hypertension. However, the role of ß2 AR vasodilatation in hypertension pathophysiology in ageing postmenopausal women is unclear. Therefore, the goals of this study were to determine if forearm vasodilatation to the selective ß2 AR agonist terbutaline is blunted in older postmenopausal women (59 ± 4 years) compared to young premenopausal women (27 ± 3 years) and to assess NO contribution to ß2 AR-mediated vasodilatation in both groups of women. Forearm blood flow (FBF) and forearm vascular conductance (FVC) were measured using venous occlusion plethysmography at baseline and during intra-arterial infusions of terbutaline at 0.1-2.0 µg (100 ml tissue)-1  min-1 with and without the NO synthase inhibitor l-NG -monomethylarginine (l-NMMA). Mean arterial pressure was significantly greater in postmenopausal women than in young women at baseline (P = 0.01). Baseline FBF and FVC did not differ between young and postmenopausal women (P > 0.05) and rose significantly within each group during terbutaline infusion (P < 0.05). There were significant group × dose interactions for FBF (P = 0.01) and FVC (P = 0.001), indicating vasodilator responses were lower in postmenopausal women. In young women, FVC response to the highest dose of terbutaline tended to be lower with l-NMMA co-infusion vs. without l-NMMA (P = 0.05). There were no significant decreases in FBF or FVC responses to terbutaline in postmenopausal women with l-NMMA co-infusion (P > 0.05 for all). These data suggest that ß2 AR responsiveness is blunted in postmenopausal women compared to young premenopausal women, and that NO may contribute to ß2 AR-mediated vasodilatation in young premenopausal women.

Asynchronous action potential discharge in human muscle sympathetic nerve activity.

What strategies are employed by the sympathetic system to communicate with the circulation? Muscle sympathetic nerve activity (MSNA) occurs in bursts of synchronous action potential (AP) discharge, yet whether between-burst asynchronous AP firing exists remains unknown. Using multiunit microneurography and a continuous wavelet transform to isolate APs, we studied AP synchronicity within human MSNA. Asynchronous APs were defined as those which occurred between bursts. Experiment 1 quantified AP synchronicity in eight individuals at baseline (BSL), -10 mmHg lower body negative pressure (LBNP), -40 mmHg LBNP, and end-expiratory apnea (APN). At BSL, 33 ± 12% of total AP activity was asynchronous. Asynchronous discharge was unchanged from BSL (67 ± 37 AP/min) to -10 mmHg LBNP (69 ± 33 AP/min), -40 mmHg LBNP (83 ± 68 AP/min), or APN (62 ± 39 AP/min). Across all conditions, asynchronous AP probability and frequency decreased with increasing AP size. Experiment 2 examined the impact of the ganglia on AP synchronicity by using nicotinic blockade (trimethaphan). The largest asynchronous APs were derecruited from BSL (11 ± 4 asynchronous AP clusters) to the last minute of the trimethaphan infusion with visible bursts (7 ± 2 asynchronous AP clusters). However, the 6 ± 2 smallest asynchronous AP clusters could not be blocked by trimethaphan and persisted to fire 100 ± 0% asynchronously without forming bursts. Nonnicotinic ganglionic mechanisms affect some, but not all, asynchronous activity. The fundamental behavior of human MSNA contains between-burst asynchronous AP discharge, which accounts for a considerable amount of BSL activity.NEW & NOTEWORTHY Historically, sympathetic nerve activity destined for the blood vessels supplying skeletal muscle (MSNA) has been characterized by spontaneous bursts formed by synchronous action potential (AP) discharge. However, this study found a considerable amount (~30% during baseline) of sympathetic AP discharge to fire asynchronously between bursts of human MSNA. Trimethaphan infusion revealed that nonnicotinic ganglionic mechanisms contribute to some, but not all, asynchronous discharge. Asynchronous sympathetic AP discharge represents a fundamental behavior of MSNA.

Vaginal Diazepam for Nonrelaxing Pelvic Floor Dysfunction: The Pharmacokinetic Profile.

BACKGROUND: Vaginal diazepam is frequently used to treat pelvic floor tension myalgia and pelvic pain despite limited knowledge of systemic absorption. AIM: To determine the pharmacokinetic and adverse event profile of diazepam vaginal suppositories. METHODS: We used a prospective pharmacokinetic design with repeated assessments of diazepam levels. Eight healthy volunteers were administered a 10-mg compounded vaginal diazepam suppository in the outpatient gynecologic clinic. Serum samples were collected at 0, 45, 90, 120, and 180 minutes; 8, 24, and 72 hours; and 1 week following administration of a 10-mg vaginal suppository. The occurrence of adverse events was assessed using the alternate step and tandem walk tests, the Brief Confusion Assessment Method, and numerical ratings. Plasma concentrations of diazepam and active long-acting metabolites were measured. Pharmacokinetic parameters were calculated by standard noncompartmental methods. RESULTS: The mean peak diazepam concentration (Cmax) of 31.0 ng/mL was detected at a mean time (Tmax) of 3.1 hours after suppository placement. The bioavailability was found to be 70.5%, and the mean terminal elimination half-life was 82 hours. The plasma levels of temazepam and nordiazepam peaked at 0.8 ng/mL at 29 hours and 6.4 ng/mL at 132 hours, respectively. Fatigue was reported by 3 of 8 participants. CLINICAL IMPLICATIONS: Serum plasma concentrations of vaginally administered diazepam are low; however the half-life is prolonged. STRENGTHS & LIMITATIONS: Strengths include use of inclusion and exclusion criteria aimed at mitigating clinical factors that could adversely impact diazepam absorption and metabolism, and the use of an ultrasensitive LC-MS/MS assay. Limitations included the lack of addressing the efficacy of vaginal diazepam in lieu of performing a pure pharmacokinetic study with healthy participants. CONCLUSION: Vaginal administration of diazepam results in lower peak serum plasma concentration, longer time to peak concentration, and lower bioavailability than standard oral use. Providers should be aware that with diazepam's long half-life, accumulating levels would occur with chronic daily doses, and steady-state levels would not be reached for up to 1 week. This profile would favor intermittent use to allow participation in physical therapy and intimacy. Larish AM, Dickson RR, Kudgus RA, et al. Vaginal Diazepam for Nonrelaxing Pelvic Floor Dysfunction: The Pharmacokinetic Profile. J Sex Med 2019;16;763-766.

The role of the paravertebral ganglia in human sympathetic neural discharge patterns.

KEY POINTS: The mechanisms affecting recruitment patterns of postganglionic sympathetic nerves remain unclear. The divergent and convergent preganglionic innervation patterns of postganglionic neurons and the presence of differently sized postganglionic nerves suggest that the ganglia may participate in modifying the discharge patterns of single sympathetic postganglionic neurons innervating the skeletal muscle circulation. Whether the ganglia affect the ordered behaviour of varying sized postganglionic sympathetic neurons in humans has not been studied. Trimethaphan infusion produced an ordered pattern of action potential (AP) de-recruitment whereby the firing of larger, low probability APs present at baseline was abolished first, followed by progressive decreased probability of smaller APs. Although integrated sympathetic bursts were no longer detected after several minutes of trimethaphan, firing of the smallest APs was detected. These data suggest the ganglia affect the distribution of firing probabilities exhibited by differently sized sympathetic neurons. The ganglia may contribute to sympathetic neural emission patterns involved in homeostatic regulation. ABSTRACT: Do the ganglia contribute to the ordered behaviour of postganglionic neuronal discharge within the sympathetic nervous system? To further understand the functional organization of the sympathetic nervous system we employed the microneurographic approach to record muscle sympathetic nerve activity (MSNA) and a continuous wavelet transform to study postganglionic action potential (AP) behaviour during nicotinic blockade at the ganglia (trimethaphan camsylate, 1-7 mg min-1 ) in seven females (37 ± 5 years). Trimethaphan elicited a progressive reduction in sympathetic outflow characterized by fewer integrated bursts with decaying amplitude. Underlying trimethaphan-mediated attenuations in integrated MSNA were reductions in AP incidence (186 ± 101 to 29 ± 31 AP (100 beats)-1 ) and AP content per integrated burst (7 ± 2 to 3 ± 1 APs burst-1 ) (both P < 0.01) in the final minute of detectable bursting activity in the trimethaphan condition, compared to baseline. We observed an ordered de-recruitment of larger to smaller AP clusters active at baseline (14 ± 3 to 8 ± 2 active AP clusters, P < 0.01). Following cessation of integrated bursts in the trimethaphan condition, the smallest 6 ± 2 sympathetic AP clusters persisted to fire in an asynchronous pattern (49 ± 41 AP (100 beats)-1 ) in all participants. Valsalva's manoeuvre did not increase the incidence of these persistent APs (60 ± 42 AP (100 beats)-1 , P = 0.52), or recruit any larger APs in six of seven participants (6 ± 1 total AP clusters, P = 0.30). These data suggest that the ganglia participate in the ordered recruitment of differently sized postganglionic sympathetic nerves.

Pharmacological assessment of the contribution of the arterial baroreflex to sympathetic discharge patterns in healthy humans.

To study how changes in baroreceptor afferent activity affect patterns of sympathetic neural activation, we manipulated arterial blood pressure with intravenous nitroprusside (NTP) and phenylephrine (PE) and measured action potential (AP) patterns with wavelet-based methodology. We hypothesized that 1) baroreflex unloading (NTP) would increase firing of low-threshold axons and recruitment of latent axons and 2) baroreflex loading (PE) would decrease firing of low-threshold axons. Heart rate (HR, ECG), arterial blood pressure (BP, brachial catheter), and muscle sympathetic nerve activity (MSNA, microneurography of peroneal nerve) were measured at baseline and during steady-state systemic, intravenous NTP (0.5-1.2 µg·kg-1·min-1, n = 13) or PE (0.2-1.0 µg·kg-1·min-1, n = 9) infusion. BP decreased and HR and integrated MSNA increased with NTP ( P < 0.01). AP incidence (326 ± 66 to 579 ± 129 APs/100 heartbeats) and AP content per integrated burst (8 ± 1 to 11 ± 2 APs/burst) increased with NTP ( P < 0.05). The firing probability of low-threshold axons increased with NTP, and recruitment of high-threshold axons was observed (22 ± 3 to 24 ± 3 max cluster number, 9 ± 1 to 11 ± 1 clusters/burst; P < 0.05). BP increased and HR and integrated MSNA decreased with PE ( P < 0.05). PE decreased AP incidence (406 ± 128 to 166 ± 42 APs/100 heartbeats) and resulted in fewer unique clusters (15 ± 2 to 9 ± 1 max cluster number, P < 0.05); components of an integrated burst (APs or clusters per burst) were not altered ( P > 0.05). These data support a hierarchical pattern of sympathetic neural activation during manipulation of baroreceptor afferent activity, with rate coding of active neurons playing the predominant role and recruitment/derecruitment of higher-threshold units occurring with steady-state hypotensive stress. NEW & NOTEWORTHY To study how changes in baroreceptor afferent activity affect patterns of sympathetic neural activation, we manipulated arterial blood pressure with intravenous nitroprusside and phenylephrine and measured sympathetic outflow with wavelet-based methodology. Baroreflex unloading increased sympathetic activity by increasing firing probability of low-threshold axons (rate coding) and recruiting new populations of high-threshold axons. Baroreflex loading decreased sympathetic activity by decreasing the firing probability of larger axons (derecruitment); however, the components of an integrated burst were unaffected.

Attitudes, Beliefs, Practices, and Concerns Among Clinicians Prescribing Opioids in a Large Academic Institution.

Objectives: Opioid treatment of chronic noncancer pain (CNCP) adds complexity and uncertainty to patient interactions. We sought to assess clinician attitudes, beliefs, practice styles, and concerns around opioid prescribing following the release of the US Centers for Disease Control and Prevention (CDC) guideline for prescribing opioids for chronic pain. Methods: E-mailed electronic survey to clinicians at a large academic medical institution. Results: A total of 961 clinicians responded to the survey (response rate = 40%), 720 of whom prescribed opioids and were not in training. Sixty-five percent were physicians, and 35% were nurse practitioners or physician assistants, with a mean age of 47 years (SD ± 11.4 years). Eighty-two percent were reluctant to prescribe opioids for CNCP, and only 47% expressed confidence in their care for CNCP patients. Sixty-seven percent were aware of the CDC guideline, 55% were enrolled in the state Prescription Drug Monitoring Program (PDMP), and 2% always or frequently prescribed naloxone to patients on opioids. Guideline awareness was associated with increased confidence in caring for CNCP patients. Clinicians having knowledge of a patient overdose were 31% more likely to be enrolled in the PDMP (relative rate= 1.31, 95% confidence interval = 1.14-1.52, chi-square = 11.00, P <0.01). Clinicians who knew of a patient overdose event were also more likely to express concern about patient opioid dependence and addiction. Conclusions: Opportunities exist to increase awareness of the CDC guideline and to increase clinician confidence in opioid prescribing. Knowledge of an overdose event may influence clinician behavior and concerns about dependence and addiction.

Corticosteroid and Cortisol Serum Levels Following Intra-articular Triamcinolone Acetonide Lumbar Facet Joint Injections.

BACKGROUND: Facet joint steroid injections are used to treat chronic low back pain. However, little is known about the systemic absorption and serum levels of steroids following intra-articular facet joint injections. The primary objective of this preliminary study was to investigate the pharmacokinetics of triamcinolone acetonide following fluoroscopically guided intra-articular lumbar facet joint injections in a cohort of patients with chronic low back pain. A secondary aim was to investigate the effects of triamcinolone on serum cortisol levels following lumbar facet joint injections. METHODS: The study cohort included 5 patients undergoing fluoroscopically guided intra-articular lumbar facet joint injections at a pain medicine specialty clinic. Blood was collected prior to the injections and on days 1, 2, 4, 6, 8, 14, 21, 28, 35, and 42 following the injections. RESULTS: The terminal elimination half-life of triamcinolone in a noncompartmental analysis was 213 hours. The peak median triamcinolone concentration of 3.6 ng/mL was detected within 24 hours after the injections. Serum cortisol levels were < 30 ng/mL for an average of 4.4 days. The maximum effect of triamcinolone on cortisol suppression was observed with triamcinolone serum levels of > 1.9 ng/mL. CONCLUSIONS: The peak serum concentration of triamcinolone following intra-articular facet joint injections occurred within 24 hours. The median terminal elimination half-life was 213 hours, but baseline cortisol levels were suppressed for an average of 4.4 days. Clinically, the prolonged half-life and endocrine effects of triamcinolone could increase the risk for serious drug-drug interactions in patients taking medications that inhibit corticosteroid metabolism.

Influence of sympathetic nerve activity on aortic hemodynamics and pulse wave velocity in women.

Central (aortic) blood pressure, arterial stiffness, and sympathetic nerve activity increase with age in women. However, it is unknown if the age-related increase in sympathetic activity influences aortic hemodynamics and carotid-femoral pulse wave velocity (cfPWV), an index of central aortic stiffness. The goal of this study was to determine if aortic hemodynamics and cfPWV are directly influenced by sympathetic nerve activity by measuring aortic hemodynamics, cfPWV, and muscle sympathetic nerve activity (MSNA) in women before and during autonomic ganglionic blockade with trimethaphan camsylate. We studied 12 young premenopausal (23 ± 4 yr) and 12 older postmenopausal (57 ± 3 yr) women. These women did not differ in body mass index or mean arterial pressure (P > 0.05 for both). At baseline, postmenopausal women had higher aortic pulse pressure, augmented pressure, augmentation index adjusted for a heart rate of 75 beats/min, wasted left ventricular pressure energy, and cfPWV than young women (P < 0.05). During ganglionic blockade, postmenopausal women had a greater decrease in these variables in comparison to young women (P < 0.05). Additionally, baseline MSNA was negatively correlated with the reductions in aortic pulse pressure, augmented pressure, and wasted left ventricular pressure energy during ganglionic blockade in postmenopausal women (P < 0.05) but not young women. Baseline MSNA was not correlated with the changes in augmentation index adjusted for a heart rate of 75 beats/min or cfPWV in either group (P > 0.05 for all). Our results suggest that some aortic hemodynamic parameters are influenced by sympathetic activity to a greater extent in older postmenopausal women than in young premenopausal women.NEW & NOTEWORTHY Autonomic ganglionic blockade results in significant decreases in multiple aortic pulse wave characteristics (e.g., augmented pressure) and central pulse wave velocity in older postmenopausal women but not in young premenopausal women. Certain aortic pulse wave parameters are negatively influenced by sympathetic activity to a greater extent in older postmenopausal women.

Multidisciplinary model to implement pharmacogenomics at the point of care.

PURPOSE: Despite potential clinical benefits, implementation of pharmacogenomics (PGx) faces many technical and clinical challenges. These challenges can be overcome with a comprehensive and systematic implementation model. METHODS: The development and implementation of PGx were organized into eight interdependent components addressing resources, governance, clinical practice, education, testing, knowledge translation, clinical decision support (CDS), and maintenance. Several aspects of implementation were assessed, including adherence to the model, production of PGx-CDS interventions, and access to educational resources. RESULTS: Between August 2012 and June 2015, 21 specific drug-gene interactions were reviewed and 18 of them were implemented in the electronic medical record as PGx-CDS interventions. There was complete adherence to the model with variable production time (98-392 days) and delay time (0-148 days). The implementation impacted approximately 1,247 unique providers and 3,788 unique patients. A total of 11 educational resources complementary to the drug-gene interactions and 5 modules specific for pharmacists were developed and implemented. CONCLUSION: A comprehensive operational model can support PGx implementation in routine prescribing. Institutions can use this model as a roadmap to support similar efforts. However, we also identified challenges that will require major multidisciplinary and multi-institutional efforts to make PGx a universal reality.Genet Med 19 4, 421-429.

Neural control of blood pressure in women: differences according to age.

PURPOSE: The blood pressure "error signal" represents the difference between an individual's mean diastolic blood pressure and the diastolic blood pressure at which 50% of cardiac cycles are associated with a muscle sympathetic nerve activity burst (the "T50"). In this study we evaluated whether T50 and the error signal related to the extent of change in blood pressure during autonomic blockade in young and older women, to study potential differences in sympathetic neural mechanisms regulating blood pressure before and after menopause. METHODS: We measured muscle sympathetic nerve activity and blood pressure in 12 premenopausal (25 ± 1 years) and 12 postmenopausal women (61 ± 2 years) before and during complete autonomic blockade with trimethaphan camsylate. RESULTS: At baseline, young women had a negative error signal (-8 ± 1 versus 2 ± 1 mmHg, p < 0.001; respectively) and lower muscle sympathetic nerve activity (15 ± 1 versus 33 ± 3 bursts/min, p < 0.001; respectively) than older women. The change in diastolic blood pressure after autonomic blockade was associated with baseline T50 in older women (r = -0.725, p = 0.008) but not in young women (r = -0.337, p = 0.29). Women with the most negative error signal had the lowest muscle sympathetic nerve activity in both groups (young: r = 0.886, p < 0.001; older: r = 0.870, p < 0.001). CONCLUSIONS: Our results suggest that there are differences in baroreflex control of muscle sympathetic nerve activity between young and older women, using the T50 and error signal analysis. This approach provides further information on autonomic control of blood pressure in women.

Potentiation of the NO-cGMP pathway and blood flow responses during dynamic exercise in healthy humans.

PURPOSE: Previous work has shown nitric oxide (NO) contributes to ~15% of the hyperemic response to dynamic exercise in healthy humans. This NO-mediated vasodilation occurs, in part, via increases in intracellular cyclic guanosine monophosphate (cGMP), which is catabolized by phosphodiesterase. We sought to examine the effect of phosphodiesterase-5 (PDE-5) inhibition on forearm blood flow (FBF) responses to dynamic handgrip exercise in healthy humans and the role of NO. We hypothesized exercise hyperemia would be augmented by sildenafil citrate (SDF, PDE-5 inhibitor). We further hypothesized any effect of SDF on exercise hyperemia would be abolished with intra-arterial infusion of the NO synthase (NOS) inhibitor L-NG-monomethyl arginine (L-NMMA). METHODS: FBF (Doppler ultrasound) was assessed at rest and during 5 min of dynamic forearm handgrip exercise at 15% of maximal voluntary contraction under control (saline) conditions and during 3 experimental protocols: (1) oral SDF (n = 10), (2) intra-arterial L-NMMA (n = 20), (3) SDF and L-NMMA (n = 10). FBF responses to intra-arterial sodium nitroprusside (NTP, NO donor) were also assessed. RESULTS: FBF increased with exercise (p < 0.01). Intra-arterial infusion of L-NMMA resulted in a reduction in exercise hyperemia (17 ± 1 to 15 ± 1 mL/dL/min, p < 0.01). Although the hyperemic response to NTP was augmented by SDF (area under the curve: 41 ± 7 vs 61 ± 11 AU, p < 0.01), there was no effect of SDF on exercise hyperemia (p = 0.33). CONCLUSIONS: Despite improving NTP-mediated vasodilation, oral SDF failed to augment exercise hyperemia in young, healthy adults. These observations reflect a minor contribution of NO and the cGMP pathway during exercise hyperemia in healthy young humans.

Re-evaluating ethical concerns in planned emergency research involving critically ill patients: an interpretation of the guidance document from the United States Food and Drug Administration.

BACKGROUND: U.S. federal regulations require that certain ethical elements be followed to protect human research subjects. The location and clinical circumstances of a proposed research study can differ substantially and can have significant implications for these ethical considerations. Both the location and clinical circumstances are particularly relevant for research in intensive care units (ICUs), where patients are often unable to provide informed consent to participate in a proposed research intervention. PURPOSE: Our goal is to elaborate on the updated 2013 U.S. Food and Drug Administration (FDA) guidance document regarding an exemption from the requirement of obtaining informed consent from patients or their surrogates and to address certain elements within that document, thereby assisting clinicians in developing a framework for emergency research in accordance with the regulatory bodies at their own institutions and in the United States. METHODS: Review of the 2011 and updated FDA guidance document on exemption from informed consent. RESULTS: The current process of obtaining informed consent within ICUs needs to be revisited, especially for research in which timely informed consent is not likely. In particular, the process of obtaining informed consent may not be appropriate or even ethical for critically ill patients in extremis who require an intervention for which there is no current acceptable standard of care and clinical equipoise exists. We provide clinicians with a viewpoint that further elaborates on the FDA guidance document. LIMITATIONS: The viewpoints provided herein are those of the authors and are therefore inherently limited by the personal views of a selected few. Other clinicians or researchers may not interpret the FDA guidelines in a similar manner. Moreover, the discussion of a guideline document is a limitation in and of itself. The guidelines set forth by the FDA are precisely that-guidelines. Therefore, they may not be followed as outlined in the guidance document within one's own institution. Our goal is that, by elaborating on the guidelines for planned research involving human subjects in the ICU, institutional regulatory bodies may gain a better understanding in drafting their own document when faced with a clinician or a researcher who wishes to conduct planned research in an ICU. CONCLUSIONS: We believe that the interpretations provided will allow clinicians to safely undertake planned research in ICUs without endangering the main tenets of ethical research involving human participants. This research is needed for the advancement of care in the critically ill.

The effect of ageing and indomethacin on forearm reactive hyperaemia in healthy adults.

We have previously shown that non-selective cyclo-oxygenase inhibition, via indomethacin, unfavourably increased central blood pressure in older adults, with little effect in young adults. In addition, the vasoactive prostaglandins have been shown to contribute to both peripheral vasodilator responses and large artery function; however, there is little information available in older adults and conflicting reports in young adults on the extent to which resistance vessel function is influenced by indomethacin. Thus, we tested the hypothesis that cyclo-oxygenase inhibition using indomethacin would attenuate forearm vascular conductance during reactive hyperaemia in older adults compared with young adults. Forearm blood flow responses to 5 min of forearm ischaemia were measured in 26 healthy adults (13 young, 25 ± 5 years old; and 13 older, 65 ± 6 years old), using venous occlusion plethysmography before and after indomethacin. Baseline forearm blood flow and vascular conductance were not different between groups during either trial, and there were no age-related differences prior to cyclo-oxygenase inhibition. Peak forearm vascular conductance and blood flow were similar between groups before indomethacin, but lower in older adults after indomethacin compared with young adults (27 ± 4 versus 41 ± 4 ml (100 ml)(-1) min(-1) (100 mmHg)(-1), P = 0.02; and 23 ± 3 versus 33 ± 3 ml (100 ml)(-1) min(-1), P = 0.02, respectively). These results, in conjunction with our previous findings in large arteries, suggest that ageing alters the effect of cyclo-oxygenase inhibition on vascular responses, and specifically, the resistance vessel responses underlying reactive hyperaemia.

Cyclo-oxygenase-2 inhibition and endothelium-dependent vasodilation in younger vs. older healthy adults.

AIM: A major feature of endothelial dysfunction is reduced endothelium-dependent vasodilation, which in ageing may be due to decreased production of endothelial prostacyclin, or nitric oxide (NO), or both. METHOD: We tested this hypothesis in 12 younger (age 18-38 years, six women) and 12 older healthy adults (age 55-73 years, six post-menopausal women). Endothelium-dependent vasodilation was assessed by the forearm vascular conductance (FVC) response to intra-arterial acetylcholine (ACh) (0.5, 1.0, 2.0, 4.0 µg dl(-1) forearm tissue min(-1) ) before and 90 min after inhibition of the enzyme cyclo-oxygenase-2 (COX-2) with oral celecoxib (400 mg), followed by the addition of endothelial NO synthase inhibition with intra-arterial N(G) -monomethyl-l arginine acetate (L-NMMA). RESULTS: Ageing was associated with a significantly reduced FVC response to ACh (P = 0.009, age-by-dose interaction; highest dose FVC ± SEM in ageing: 11.2 ± 1.4 vs. younger: 17.7 ± 2.4 units, P = 0.02). Celecoxib did not reduce resting FVC or the responses to ACh in any group. L-NMMA significantly reduced resting FVC and the responses to ACh in all groups, and absolute FVC values following L-NMMA were similar between groups. CONCLUSION: In healthy normotensive younger and older adults, there is minimal contribution of prostacyclin to ACh-mediated vasodilation, yet the NO component of vasodilation is reduced with ageing. In the clinical context, these findings suggest that acute administration of medications that inhibit prostacyclin (i.e. COX-2 inhibitors) evoke modest vascular consequences in healthy persons. Additional studies are necessary to test whether chronic use of COX-2 medications reduces endothelium dependent vasodilation in older persons with or without cardiovascular risk factors.

Impact of sex on antidepressant discontinuation in groups of similar cytochrome P450 phenotypes.

Introduction: Although there are studies assessing reasons for antidepressant discontinuation, little is known about the impact of sex differences or cytochrome P450 phenotypes. Our objective is to assess discontinuation rates between males and females and whether CYP450 phenotype influences discontinuation. Methods: This is a retrospective review of patients previously enrolled in the Right Drug, Right Dose, Right Time: Using Genomic Data to Individualize Treatment database with major depressive disorder. Patients were evaluated for antidepressants trialed between January 1, 2009, and September 30, 2019. Survival analyses with competing risks were used to analyze discontinuation reasons. A Kaplan-Meier estimation method was used to assess the time to discontinuation and discontinuation rates. Analyses were also completed to assess discontinuation between men and women by phenotypic groups. All tests were two-sided, and p-values ≤ .05 were considered statistically significant. Results: There were 620 antidepressant discontinuation events discovered from 1015 antidepressant trials included. Overall, the median time to discontinuation for males was 2.6 years and 1.9 years for females (hazard ratio [HR] 0.97 [95% confidence interval (CI): 0.80, 1.19], p = .77). The risk of discontinuation was not different between males and females in any of the phenotype groups, which was consistent in the multivariable analyses. Concomitant use of medications that inhibited or induced antidepressant metabolism increased the overall risk of discontinuation (HR 1.45, 95% CI [1.06, 1.99], p = .020) in a time-dependent analysis. Discussion: We did not detect a significant difference in risk of antidepressant discontinuation rates between males and females even when accounting for cytochrome P450 phenotype. Future studies should account for whether medications that inhibit or induce antidepressant metabolism may be a crucial factor in antidepressant discontinuation.