Antiplatelet therapy guided by CYP2C19 point-of-care pharmacogenetics plus multidimensional treatment decisions

Aim: Implementation of CYP2C19 point-of-care (POC) pharmacogenetic (PGx) testing with personalized treatment recommendations. Methods: POC CYP2C19 genotyping plus expert evaluation of risk factors for ischemic and bleeding events. Results: 167 patients underwent PGx testing, 54 (32.3%) were CYP2C19 loss of function carriers, and POC versus standard PGx analysis results for *2 and *3 variants matched in 100%. Antiplatelet therapy was adjusted in 44 patients (26.3%), but always required consideration of patient-specific factors. Conclusion: CYP2C19 POC-PGx is reliable and offers clinically relevant advantages for immediate evidence-based adaptations of antiplatelet therapy, whereas in less acute cases conventional PGx testing can also have advantages. Antiplatelet therapy has become more complex, and implementation of PGx-based personalized antiplatelet therapy requires complementary expert knowledge.

Allergy-like immediate reactions with herbal medicines in children: A retrospective study using data from VigiBase®

BACKGROUND

The use of herbal medicines in children and the general population is continually on the rise with an overall herbal lifetime and current use ranging between 0.8%-85.5% and 2.2%-8.9%, respectively. Although acute hypersensitivity reactions are generally considered to be rare, little knowledge exists on the frequency and type of these reactions especially in specific populations like children.

OBJECTIVES

To assess the patterns of acute hypersensitivity reactions to herbal medicines reported to the WHO global individual case safety report (ICSR) database VigiBase^® in children.

STUDY DESIGN

From the original VigiBase^® extract for the time between 1968 and 2014, we included all reports with adverse drug reactions (ADR) associated with herbal medicines in children where WHO-ART reaction terms were indicative of acute hypersensitivity reactions.

RESULTS

VigiBase^® contained 2646 ICSRs with 14 860 distinct adverse reactions reported in association with herbal medicine in children. Among those, 79 cases with 107 allergy-like reactions met our inclusion criteria. The most commonly reported WHO-ART terms were urticaria or rash/rash erythematous (59.8%), and allergic reaction (8.4%). The most frequently reported suspected herbal medicines were mixed herbal products (51.4%), Hedera helix (15.0%), and Echinacea purpurea (5.6%). Most frequent routes of administration were oral (75.9%), topical (8.9%), and rectal (3.8%). Over 30% of cases were reported in the age group from 7 to 12 years. The majority of reports were received from Germany (29.1%), Thailand (21.5%), and Australia (11.4%).

CONCLUSION

VigiBase^® contains a considerable number of acute hypersensitivity reactions in children associated with herbal medicines, including life-threatening reactions such as anaphylactic shock.

Development, implementation and outcome analysis of semi-automated alerts for metformin dose adjustment in hospitalized patients with renal impairment

PURPOSE

Overdosing of the oral antidiabetic metformin in impaired renal function is an important contributory cause to life-threatening lactic acidosis. The presented project aimed to quantify and prevent this avoidable medication error in clinical practice.

METHODS

We developed and implemented an algorithm into a hospital's clinical information system that prospectively identifies metformin prescriptions if the estimated glomerular filtration rate is below 60 mL/min. Resulting real-time electronic alerts are sent to clinical pharmacologists and pharmacists, who validate cases in electronic medical records and contact prescribing physicians with recommendations if necessary.

RESULTS

The screening algorithm has been used in routine clinical practice for 3 years and generated 2145 automated alerts (about 2 per day). Validated expert recommendations regarding metformin therapy, i.e., dose reduction or stop, were issued for 381 patients (about 3 per week). Follow-up was available for 257 cases, and prescribers' compliance with recommendations was 79%. Furthermore, during 3 years, we identified eight local cases of lactic acidosis associated with metformin therapy in renal impairment that could not be prevented, e.g., because metformin overdosing had occurred before hospitalization.

CONCLUSIONS

Automated sensitive screening followed by specific expert evaluation and personal recommendations can prevent metformin overdosing in renal impairment with high efficiency and efficacy. Repeated cases of metformin-associated lactic acidosis in renal impairment underline the clinical relevance of this medication error. Our locally developed and customized alert system is a successful proof of concept for a proactive clinical drug safety program that is now expanded to other clinically and economically relevant medication errors. Copyright © 2016 John Wiley & Sons, Ltd.

Drug safety of macrolide and quinolone antibiotics in a tertiary care hospital: administration of interacting co-medication and QT prolongation

PURPOSE

Some macrolide and quinolone antibiotics (MQABs) are associated with QT prolongation and life-threatening torsade de pointes (TdP) arrhythmia. MQAB may also inhibit cytochrome P450 isoenzymes and thereby cause pharmacokinetic drug interactions (DDIs). There is limited data on the frequency and management of such risks in clinical practice. We aimed to quantify co-administration of MQAB with interacting drugs and associated adverse drug reactions.

METHODS

We conducted an observational study within our pharmacoepidemiological database derived from electronic medical records of a tertiary care hospital. Among all users of MQAB associated with TdP, we determined the prevalence of additional QT-prolonging drugs and risk factors and identified contraindicated co-administrations of simvastatin, atorvastatin, or tizanidine. Electrocardiographic (ECG) monitoring and associated adverse events were validated in medical records.

RESULTS

Among 3444 administered courses of clarithromycin, erythromycin, azithromycin, ciprofloxacin, levofloxacin, or moxifloxacin, there were 1332 (38.7 %) with concomitant use of additional QT-prolonging drugs. Among those, we identified seven cases of drug-related QT prolongation, but 49.1 % had no ECG monitoring. Of all MQAB users, 547 (15.9 %) had hypokalemia. Forty-four MQAB users had contraindicated co-administrations of simvastatin, atorvastatin, or tizanidine and three of those related adverse drug reactions.

CONCLUSION

In the studied real-life setting, we found a considerable number of MQAB users with additional risk factors for TdP but no ECG monitoring. However, adverse drug reactions were rarely found, and costs vs. benefits of ECG monitoring have to be weighted. In contrast, avoidable risk factors and selected contraindicated pharmacokinetic interactions are clear targets for implementation as automated alerts in electronic prescribing systems.