Comparison of the antiarrhythmic potential of doxapram and its metabolite ketodoxaparam

Background

A few years ago, the TASK-1 channel has been established as a potential new target for the therapy of atrial fibrillation (AF). In the heart, TASK-1 is almost exclusively expressed in the atria and is significantly upregulated in AF patients. Therefore, it plays an important role in the shortening of the atrial action potential observed during AF, making TASK-1 a promising target for AF therapy. This could be proven in a porcine model of persistent AF in which an intravenous application of the TASK-1 inhibitor doxapram led to a termination of AF and the restoration of sinus rhythm (SR). Doxapram's metabolite ketodoxapam is described in the literature as being active with limited data available on its usage. Therefore, the effect of ketodoxapram on TASK-1 and its possible use in AF therapy still needs to be investigated.

Purpose

The purpose of the present study was to assess the potential of ketodoxapram in the termination of AF. Furthermore, a comparison between doxapram and ketodoxapram was performed based on electrophysiological and pharmacological data.

Methods

UPLC-MS/MS assays were developed and validated for the measurement of doxapram and ketodoxapram in porcine plasma and brain tissue. Using these assays, the pharmacokinetics of both substances, after intravenous injections of 1 mg/kg, were determined in pigs. Furthermore, brain and plasma concentrations were measured to assess brain-to-plasma ratios. A porcine AF model was used to estimate the antiarrhythmic potential. Electrophysiological properties were evaluated, using two-electrode voltage clamp experiment on Xenopus laevis oocytes which heterologously expressed atrial potassium channels, to calculate the effect of doxapram and ketodoxapram on channel function. Furthermore, whole-cell patch clamp measurements were performed on isolated human cardiomyocytes.

Results

Doxapram and ketodoxapram showed strong inhibitory effects on TASK-1 (IC50 1.0 μM and 0.8 μM) and TASK-3 (5.9 μM and 1.5 μM), but no significant effect on the other measured ion channels. The maximal inhibition on TASK-1 was 96%. The brain-to-plasma ratio for doxapram (0.58) was almost ten-fold higher than for ketodoxapram (0.065), hinting at a reduced crossing of the blood-brain barrier (BBB) for ketodoxapram. The terminal half-life (t1/2) of ketodoxapram (1.71 h) was longer and the maximal concentration (Cmax; 4,604 ng/ml) was higher than for doxapram (1.38 h; 1,780 ng/ml). In a porcine model of AF, ketodoxapram led to a significantly reduced AF burdens comparable to doxapram.

Conclusions

Doxapram and ketodoxapram both show strong inhibitory effects on TASK-1, making them good candidates for a TASK-1 based AF therapy. Ketodoxapram with its longer t1/2, reduced crossing of the BBB and higher Cmax points towards a possible superiority in the treatment of AF compared to doxapram. Studies in a porcine AF model showed promising results for the use of doxapram and ketodoxapram in AF therapy.

Funding Acknowledgement

Type of funding sources: Public grant(s) – National budget only. Main funding source(s): German Research Foundation

Assessing the perspective of well-being of older patients with multiple morbidities by using the LAVA tool - a person-centered approach

Background

Older patients with multiple morbidities are a particularly vulnerable population that is likely to face complex medical decisions at some time in their lives. A patient-centered medical care fosters the inclusion of the patients’ perspectives, priorities, and complaints into clinical decision making.

Methods

This article presents a short and non-normative assessment tool to capture the priorities and problems of older patients. The so-called LAVA (“Life and Vitality Assessment”) tool was developed for practical use in seniors in the general population and for residents in nursing homes in order to gain more knowledge about the patients themselves as well as to facilitate access to the patients. The LAVA tool conceptualizes well-being from the perspectives of older individuals themselves rather than from the perspectives of outside individuals.

Results

The LAVA tool is graphically presented and the assessment is explained in detail. Exemplarily, the outcomes of the assessments with the LAVA of three multimorbid older patients are presented and discussed. In each case, the assessment pointed out resources as well as at least one problem area, rated as very important by the patients themselves.

Conclusions

The LAVA tool is a short, non-normative, and useful approach that encapsulates the perspectives of well-being of multimorbid patients and gives insights into their resources and problem areas.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12877-021-02342-3.

1206Doxapram is a promising new antiarrhythmic drug for an atrial-specific therapy of atrial fibrillation

Background

TASK-1 (K2P3.1) is an atrial-specific two-pore domain potassium channel that is significantly upregulated in atrial fibrillation (AF) patients resulting in shortened atrial action potential duration (APD). Inhibition of TASK-1 in human atrial cardiomyocytes reverses AF-related APD shortening to values observed in patients with sinus rhythm (SR). By in silico-modelling and experimental characterization of drug binding sites, doxapram was identified as specific inhibitor of TASK-1.

Purpose

In this study, we investigated the antiarrhythmic efficacy of doxapram in a porcine model of AF to convert and suppress AF.

Methods

We established a new porcine model of persistent AF without induced tachymyopathy. AF was induced in domestic pigs by intermittent atrial burst stimulation using implanted pacemakers. During AF episodes, burst stimulation was inhibited by an integrated pacemaker biofeedback algorithm. AV-node ablation was performed to prevent AF-associated heart failure. All pigs underwent catheter-based electrophysiological investigations prior to and after 14 days doxapram treatment. Pigs in the treatment group received intravenous applications of doxapram twice per day. Rhythm status was continuously recorded by intracardiac long-term ECG monitors. The application of doxapram for cardioversion and long term suppression of AF in pigs with persistent AF was evaluated. Subsequent to the doxapram treatment, porcine cardiomyocytes were isolated from right and left atria and electrophysiologically investigated by patch-clamp and multi-electrode experiments. Atrial electrical remodeling was characterized by analyses of ion channel expression at mRNA and protein levels.

Results

TASK-1 mRNA, protein and transmembrane current were significantly increased in AF pigs compared to SR controls, resulting in shortened atrial APDs. In doxapram-treated AF pigs the AF burden was significantly reduced. After 14 days treatment with doxapram, TASK-1 currents and atrial APDs recorded in porcine cardiomyocytes were reduced and similar to values of SR animals. Doxapram could be successfully applied for cardioversion in pigs with persistent AF. On average, cardioversion was observed 3 minutes after doxapram application.

Conclusion

Doxapram significantly suppressed AF episodes and normalized cellular electrophysiological characteristics in a porcine model of AF through inhibition of the TASK-1 ion channel. Furthermore, doxapram rapidly converted AF into SR in pigs. Therefore, doxapram might serve as a new antiarrhythmic drug to treat AF in patients.

[Epidemiology and prevention of heat-related adverse health effects on elderly people]

Heat waves increase the morbidity and mortality in Germany, particularly of older patients in need of care. Due to climate change the number of heat waves in Germany will increase threefold by the end of the century. In addition, the proportion of patients at risk will grow due to demographic change. Therefore, the Government and the Federal States have developed recommendations for heat action plans, in which the medical profession should also participate in the prevention of heat-related damage to health. Physicians and their team should first become acquainted with the topic. In addition, they should inform patients at risk and their relatives of the risks and preventive measures. In the summer a critical check of drugs is also needed because medications impair cooling mechanisms in heat waves, the pharmacokinetics can change and unwanted side effects of drugs occur more frequently. Lastly, due to their central position in the healthcare system, physicians should participate in the coordination of a good nursing care and intensification of social contacts during heat waves.

Association of generalized anxiety symptoms and panic with health care costs in older age-Results from the ESTHER cohort study

BACKGROUND

Little is known specifically about the association between generalized anxiety symptoms or panic and health care costs in older age. The aim of this study was to examine the association between generalized anxiety symptoms, panic and health care costs in people aged 65 and over.

METHODS

Cross-sectional data from the 8-year follow-up of a large, prospective cohort study, the ESTHER study, was used. Individuals aged 65 and over, who participated in the study's home assessment, were included in this analysis (n = 2348). Total and sectoral costs were analyzed as a function of either anxiety symptoms, probable panic disorder, or a panic attack, while controlling for selected covariates, using Two Part and Generalized Linear Models. Covariates were chosen based on Andersen's Behavioral Model of Health Care Use.

RESULTS

There was no significant association between either of the anxiety or panic measures and total health care costs. Stratified by health care sectors, only the occurrence of a panic attack was significantly associated with incurring costs for outpatient non-physician services (OR: 1.99; 95% CI: 1.15-3.45) and inpatient services (OR: 2.14; 95% CI: 1.07-4.28). Other illness-related factors, such as comorbidities and depressive symptoms, were associated with health care costs in several models.

LIMITATIONS

This was a cross-sectional study relying on self-reported data.

CONCLUSION

This study points to an association between a panic attack and sector-specific health care costs in people aged 65 and over. Further research, especially using longitudinal data, is needed.

A randomized controlled trial to assess the effect of a medication plan containing drug administration recommendations on patients' drug knowledge after 2 months

WHAT IS KNOWN AND OBJECTIVE

Patients' drug administration errors are often promoted by poor drug knowledge resulting from inadequate oral or written information. It has previously been shown that a medication plan enhanced with graphical and textual information on drug handling (enhanced medication plan) proved to immediately increase patients' drug knowledge. This study aimed to evaluate the effect of the enhanced medication plan on drug knowledge in outpatients after 2 months (intervention group) compared to patients with a simple medication plan with standard information (control group).

METHODS

We recruited patients using ≥5 drugs in four family practices in Germany. After inclusion, patients' knowledge on handling of their drugs was assessed using three questions from a standardized catalog. Thereafter, patients were randomized to the intervention or control group. After 2 months, drug knowledge was reassessed with three different questions from the same standardized catalog.

RESULTS AND DISCUSSION

Of 120 enrolled patients, 75% of participants in the control group (42/60 patients) and 78% of participants in the intervention group (46/60; P = 0·71) completed the study. Baseline drug knowledge was similar in both groups (43·7% vs. 40·6% correct answers). After 2 months, patients' drug knowledge showed an absolute increase of 23·2% in the intervention group (P < 0·01) and was unchanged in the control group (46·0%; P = 0·70).

WHAT IS NEW AND CONCLUSION

The enhanced medication plan outperformed the effect of a simple medication plan and persistently increased the fraction of correct answers of polypharmacy patients. This demonstrates that the enhanced medication plan may be a useful tool in promoting drug knowledge.

[Formal prescribing errors are substantially reduced in electronic prescribing and after teaching sessions]

INTRODUCTION

Prescription forms enable the communication between physicians and pharmacists. Hence, incorrectly issued prescriptions may result in delay of health-care delivery, additional workload, and potentially adverse patient outcomes. We aimed to evaluate the formal prescription quality in our outpatient clinics (OC) before and after performing teaching sessions and using an electronic prescription system to replace handwritten prescriptions.

METHODS

All OCs of a university hospital were offered a short teaching session on how to issue prescriptions correctly and how to use the electronic prescription system. During four weeks before and after the teaching, we anonymously collected all prescriptions of the OCs in 20 surrounding community pharmacies and assessed whether they were error-free, required an intervention by the pharmacist, additional clarification by the OC, or had to be reissued.

RESULTS

After the intervention, the absolute fraction of formally error-free prescriptions increased by 12.9% from 52.9% (516/976) to 65.8% (713/1084, p < 0.001; d = 12,9% 95% confidence interval [8,7%; 17,1%]). Largest improvements were seen in prescriptions requiring clarification by the OC (224/976 prescriptions at baseline versus 93/1084 post-intervention, p < 0.001). The fraction of electronic prescriptions increased from 34.9% (341/976) to 46.9% (509/1084, p < 0.001, d = 12,0% 95% confidence interval [7,8%; 16,2%]) with electronic prescriptions consistently being of higher formal quality than handwritten prescriptions.

CONCLUSION

After increased use of electronic prescribing and teaching courses, formal prescription quality was significantly improved.

[Which Factors Affect Out-of-pocket Payments for Health Care Services Among Elderly Germans? Results of a Longitudinal Study]

Background: In Germany, out-of-pocket payments (OOPP) account for a large proportion of total health expenditure. However, there are only few investigations on how morbidity-related, sociodemographic and lifestyle factors affect OOPP particularly in the older population. The aim of this study was to identify factors affecting OOPP for health care services among elderly Germans in a longitudinal setting. Methods: This longitudinal study used data from 2 follow-up waves (3-year interval) from a population-based prospective cohort study (ESTHER study) collected in Saarland, Germany. At the first follow-up wave, subjects were between 57 and 84 years old. Participants provided comprehensive data including individual OOPP for the preceding 3 months. Fixed effects (FE) regressions were used to determine factors affecting OOPP. Results: Mean individual OOPP (3-month period) rose from € 119 (first wave) to € 136 (second wave). Longitudinal regressions showed that higher morbidity did not affect OOPP. Moreover, changes in sociodemographic as well as lifestyle factors were not related to changes in OOPP. Solely, exemption of OOPP reduced the dependent variable significantly. Conclusion: In contrast to cross-sectional findings for Germany, OOPP are not related to morbidity and income in this study. This underlines the complex nature of OOPP in old age and the need for longitudinal studies to gain some insight into the underlying causal factors.

[Use and potential risks of over-the-counter analgesics]

BACKGROUND AND AIM

We investigated the use of prescription and non-prescription (over-the-counter, OTC) analgesics and the associated risks in elderly patients with multiple morbidities.

METHODS

Pain medication use was evaluated from the baseline data (2008/2009) of the MultiCare cohort enrolling elderly patients with multiple morbidities who were treated by primary care physicians (trial registration: ISRCTN89818205). We considered opioids (N02A), other analgesics, and antipyretics (N02B) as well as nonsteroidal anti-inflammatory drugs (NSAIDs; M01A). OTC use, duplicate prescription, dosages, and interactions were examined for acetylsalicylic acid, diclofenac, (dex)ibuprofen, naproxen, and acetaminophen.

RESULTS

Of 3,189 patients with multiple morbidities aged 65-85 years, 1,170 patients reported to have taken at least one prescription or non-prescription analgesic within the last 3 months (36.7 %). Of these, 289 patients (24.7 % of 1,170) took at least one OTC analgesic. Duplicate prescription was observed in 86 cases; 15 of these cases took the analgesics regularly. In two cases, the maximum daily dose of diclofenac was exceeded due to duplicate prescription. In 235 cases, patients concurrently took a drug with a potentially clinically relevant interaction. In 43 cases (18.3 % of 235) an OTC analgesic, usually ibuprofen, was involved.

DISCUSSION

About one third of the elderly patients took analgesics regularly or as needed. Despite the relatively high use of OTC analgesics, the proportions of duplicate prescription, medication overdoses, and adverse interactions due to OTC products was low.

More than just crushing: a prospective pre-post intervention study to reduce drug preparation errors in patients with feeding tubes

WHAT IS KNOWN AND OBJECTIVES

Incorrect drug preparation for patients with feeding tubes can result in harm for the patient and the preparing person. Combined intervention programs are effective tools to reduce such preparation errors. However, to date, intervention programs have been mostly tested in hospitals with computerized physician order entry (CPOE), unit-dose systems, or ward-based clinical pharmacists. Hence, the primary objective of this study was to develop and evaluate an intervention program tailored to hospitals without such preconditions.

METHODS

We conducted a prospective pre-/post-intervention study on a gastroenterological intensive care unit (ICU) and a surgical ward for oral, dental and maxillofacial diseases (surgical ward). During the study periods, observers documented and evaluated drug preparation processes of all peroral drugs for patients with feeding tubes. The primary endpoint was the rate of inappropriately crushed and/or suspended solid peroral drugs in regards to all solid peroral drugs.

RESULTS AND DISCUSSION

Altogether, we evaluated 775 drug preparation processes of solid peroral drugs on the ICU and 975 on the surgical ward. The intervention program significantly reduced incorrect crushing and/or suspending of solid peroral drugs for administration to patients with feeding tubes from 9·8% to 4·2% (P < 0·01) on the ICU and from 5·7% to 1·4% (P < 0·01) on the surgical ward.

WHAT IS NEW AND CONCLUSION

The implementation of the newly developed intervention program significantly reduced the rate of inappropriately prepared solid peroral drugs, suggesting that it is an effective measure to enable safe drug administration for inpatients with feeding tubes.

Memorandum on the use of information technology to improve medication safety

BACKGROUND

Information technology in health care has a clear potential to improve the quality and efficiency of health care, especially in the area of medication processes. On the other hand, existing studies show possible adverse effects on patient safety when IT for medication-related processes is developed, introduced or used inappropriately.

OBJECTIVES

To summarize definitions and observations on IT usage in pharmacotherapy and to derive recommendations and future research priorities for decision makers and domain experts.

METHODS

This memorandum was developed in a consensus-based iterative process that included workshops and e-mail discussions among 21 experts coordinated by the Drug Information Systems Working Group of the German Society for Medical Informatics, Biometry and Epidemiology (GMDS).

RESULTS

The recommendations address, among other things, a stepwise and comprehensive strategy for IT usage in medication processes, the integration of contextual information for alert generation, the involvement of patients, the semantic integration of information resources, usability and adaptability of IT solutions, and the need for their continuous evaluation.

CONCLUSION

Information technology can help to improve medication safety. However, challenges remain regarding access to information, quality of information, and measurable benefits.

Discussion of "Attitude of physicians towards automatic alerting in computerized physician order entry systems"

With these comments on the paper "Attitude of Physicians Towards Automatic Alerting in Computerized Physician Order Entry Systems", written by Martin Jung and co-authors, with Dr. Elske Ammenwerth as senior author [1], the journal wants to stimulate a broad discussion on computerized physician order entry systems. An international group of experts have been invited by the editor of Methods to comment on this paper. Each of the invited commentaries forms one section of this paper.

[HeiCare®: a project aiming to improve medication communication across health care sectors]

BACKGROUND AND OBJECTIVE

Changes between health care sectors represent a critical phase in long-term pharmacotherapy. The aim of the Hei CARE(®) project was to close the communication gap at the interface between primary care physicians (PCP), hospital physicians and patients, and to improve quality and safety of pharmacotherapy.

METHODS

Physicians who enrolled patients with long-term pharmacotherapy were able to participate in the Hei CARE(®) project. After enrolment the patient's medication was entered in the internet-based medication knowledge data base AiD PRAXIS and checked for medication interactions and optimized if necessary. At hospitalisation medication was transferred electronically to the hospital (AiD KLINIK(®)) and on discharge integrated in the discharge letter and faxed to the primary care physician (PCP). The project was evaluated using quantitative and qualitative methods. Hei CARE(®) -cases, in which medication was transferred electronically as planned, were compared with the other cases. PCPs' experiences were collected in focus groups.

RESULTS

One thousand and three chronically ill patients of 56 primary care practices participated. 259 patients were hospitalized between October 2005 and March 2009 of which entrance and discharge medication were transferred both ways via the electronic prescribing platform in 67 cases. The number of changes in medication was reduced in comparison to the other cases. Participating PCPs reported positive changes through Hei CARE(®) as well as further potential for optimizing communication across health care sectors.

CONCLUSION

Use of a common internet-based medication knowledge data base (Hei CARE(®) ) in both health care sectors reduced the number of changes in pharmacotherapy. Seamless care in chronically ill patients was thereby improved. The project also demonstrated that improving communication across health care sectors is a slow process.

Determining the time course of CYP3A inhibition by potent reversible and irreversible CYP3A inhibitors using A limited sampling strategy

We established a new limited sampling strategy to assess CYP3A activity and evaluated the time course of reversible (voriconazole) and irreversible (ritonavir) CYP3A inhibition. In this randomized trial, two groups, each with eight healthy participants, received CYP3A inhibitors voriconazole or ritonavir orally for 9 days, with 3 mg midazolam (MDZ) administered before the inhibitor treatment, on days 1, 2, 3, 5, 8, and 9 during inhibitor treatment, and on days 10, 11, and 12 (3 days) after discontinuation. Plasma MDZ area under the curve (AUC) between 2 and 4 h after oral administration in the form of a solution strongly correlated with MDZ clearance. Using this parameter, maximum inhibition of voriconazole and ritonavir was calculated to have occurred only 48 h after starting of the inhibitor (percentage of baseline MDZ clearance, voriconazole: 10.6%; ritonavir: 8.4%). Recovery of CYP3A activity occurred with a half-life of 24 h after voriconazole, whereas ritonavir inhibition was still strong 3 days after discontinuation. These findings underscore the substantial and gradual alterations in dose requirements in the first days of and after such combination therapies.

Effect of rifampicin and CYP2B6 genotype on long-term efavirenz autoinduction and plasma exposure in HIV patients with or without tuberculosis

We performed a prospective comparative study to examine, from a pharmacogenetics perspective, the effect of rifampicin (RIF) on long-term efavirenz (EFV) autoinduction and kinetics. In a study population of patients with HIV receiving EFV with RIF (arm 2, n = 54) or without RIF (arm 1, n = 128 controls), intraindividual and interindividual plasma EFV and 8-hydroxyefavirenz levels were compared at weeks 4 and 16 of EFV therapy. In arm 2, RIF was initiated 4 weeks before starting EFV. In controls (arm 1), the plasma EFV was significantly lower whereas 8-hydroxyefavirenz was higher at week 16 as compared to week 4. By contrast, there were no significant differences in plasma EFV and 8-hydroxyefavirenz concentrations over time in arm 2. At week 4, the plasma EFV concentration was significantly lower in arm 2 as compared to arm 1, but no significant differences were observed by week 16. When stratified by CYP2B6 genotype, significant differences were observed only with respect to CYP2B6*1/*1 genotypes. Ours is the first report of the CYP2B6 genotype-dependent effect of RIF on long-term EFV autoinduction.

Design and evaluation of an ontology-based drug application database

OBJECTIVES

Several recently published cases of preventable adverse drug reactions were associated with flaws in drug application. However, current clinical decision support (CDS) systems do not properly consider drug application issues and thus do not support effective prevention of such medication errors. With the aim to improve CDS in this respect, we developed a comprehensive model precisely describing all aspects of drug application.

METHODS

The model consists of 1) a schema comprising all relevant attributes of drug application and 2) an ontology providing a hierarchically structured vocabulary of terms that describe the possible values of the schema's attributes. Finally, medical products were annotated by a semi-automatic term assignment process. For evaluation, we developed an algorithm that uses our model to compute a meaningful similarity between medicinal products with respect to their drug application characteristics.

RESULTS

Our schema consists of 22 attributes. The ontology contains 248 terms, textual descriptions, and synonym lists. More than 58,700 medicinal products were automatically annotated with >386,600 terms. 2,450 drugs were manually reviewed by experts, adding >4500 terms. The annotation and similarity measure allow for (similarity) searches, clustering, and proper discrimination of drugs with different drug application characteristics. We demonstrated the value of our approach by means of a set of case studies.

CONCLUSION

Our model enables a detailed description of drug application, allowing for semantically meaningful comparisons of drugs. This is an important prerequisite for improving the ability of CDS systems to prevent prescription errors.

Long-term efavirenz autoinduction and its effect on plasma exposure in HIV patients

We investigated the influence of gender and pharmacogenetic variations on long-term efavirenz autoinduction and disposition among patients with HIV in Tanzania (N = 129). Plasma concentrations (at 16 h) of efavirenz and 8-hydroxyefavirenz were quantified at weeks 4 and 16 of therapy. Genotyping was performed to identify cytochrome P450 (CYP) 2B6*6, CYP3A5*3, *6, and *7, and ABCB1-3435 C/T genotypes. There were reductions in the median efavirenz concentration (Wilcoxon matched-pair test P < 0.001) and efavirenz/8-hydroxyefavirenz ratio (P < 0.001) by 19 and 32%, respectively, at week 16 as compared with week 4. The proportion of patients with efavirenz concentration <1 µg/ml at week 16 was higher by 67, 25, and 5% in CYP2B6*1/*1, *1/*6, and *6/*6 genotypes, respectively. The defined therapeutic range based on observed plasma concentrations is affected by the time point of sampling and the CYP2B6 genotype. The effect of efavirenz autoinduction on reducing plasma exposure continues up to week 16 and predominantly affects CYP2B6 extensive metabolizers. Among CYP2B6 slow metabolizers, the presence of a CYP3A5 genotype allele is associated with greater effects of efavirenz autoinduction on plasma concentrations of the drug. The cumulative induction may influence the long-term antiretroviral therapy outcome, particularly in CYP2B6*1 carriers.

Patient-specific electronic decision support reduces prescription of excessive doses

OBJECTIVES

Prescription of excessive doses is the most common prescription error, provoking dose-dependent adverse drug reactions. Clinical decision support systems (CDSS) can prevent prescription errors especially when mainly clinically relevant warnings are issued. We have built and evaluated a CDSS providing upper dose limits personalised to individual patient characteristics thus guaranteeing for specific warnings.

METHODS

For 170 compounds, detailed information on upper dose limits (according to the drug label) was compiled. A comprehensive software-algorithm extracted relevant patient information from the electronic chart (eg, age, renal function, comedication). The CDSS was integrated into the local prescribing platform for outpatients and patients at discharge, providing immediate dosage feedback. Its impact was evaluated in a 90-day intervention study (phase 1: baseline; phase 2: intervention). Outcome measures were frequency of excessive doses before and after intervention considering potential induction of new medication errors. Moreover, predictors for alert adherence were analysed.

RESULTS

In phase 1, 552 of 12,197 (4.5%) prescriptions exceeded upper dose limits. In phase 2, initially 559 warnings were triggered (4.8%, p=0.37). Physicians were responsive to one in four warnings mostly adjusting dosages. Thus, the final prescription rate of excessive doses was reduced to 3.6%, with 20% less excessive doses compared with baseline (p<0.001). No new manifest prescription errors were induced. Physicians' alert adherence correlated with patients' age, prescribed drug class, and reason for the alert.

CONCLUSION

During the 90-day study, implementation of a highly specific algorithm-based CDSS substantially improved prescribing quality with a high acceptance rate compared with previous studies.

Prospective pilot intervention study to prevent medication errors in drugs administered to children by mouth or gastric tube: a programme for nurses, physicians and parents

BACKGROUND

Drug administration in children is an error-prone task for nurses and parents because individual dose adjustment is often necessary, and suitable formulations for children are frequently lacking. Hence, in the absence of measures for their prevention, medication errors are likely to occur.

OBJECTIVE

To assess the error prevalence in drug administration by mouth or gastric tube before and after implementing a programme for quality improvement for nurses and parents.

DESIGN, SETTING AND PARTICIPANTS

Prospective, two-period cohort intervention study on a paediatric neurology ward of a university hospital where drug administration procedures of nurses and parents were consecutively monitored during the routine drug administration hours.

MAIN OUTCOMES MEASURE

Prevalence of administration errors before and after implementing instructions for appropriate drug administration, and a teaching and training programme supported by information pamphlets.

RESULTS

Altogether, 1164 predefined administration tasks were assessed, 675 before and 489 after the intervention. Of these, 95.7% (after the

INTERVENTION

92.6%) were performed by nurses. Errors addressed by the intervention were reduced from 261/646 tasks (40.4%) to 36/453 (7.9%, p<0.001) in nurses and from 28/29 (96.6%) to 2/36 (5.6%, p<0.001) in parents. Errors in predefined categories concerning tablet dissolution, tablet storage, oral liquids, tablet splitting, administration by gastric tube and others were all considerably less frequent after the intervention (each p<0.001).

CONCLUSION

Errors of drug administration by mouth and gastric tube represent a considerable and often neglected drug-related problem in paediatric inpatients. Targeted quality-improvement programmes can substantially and rapidly reduce error prevalence. Appropriate teaching and training of both nurses and parents supported by pamphlets was a highly efficient way to reduce error prevalence.

Effect of simultaneous induction and inhibition of CYP3A by St John's Wort and ritonavir on CYP3A activity

We aimed to assess the effect of coadministration and withdrawal of a potent cytochrome P450 3A (CYP3A) inhibitor (ritonavir) and a potent CYP3A inducer (St John's wort) on CYP3A enzyme activity in an open, fixed-sequence study design. We investigated the pharmacokinetics of midazolam: (i) at baseline, (ii) after a single dose of either St John's wort or ritonavir (each n = 6), (iii) after 14 days of coadministration of ritonavir (300 mg b.i.d.) and St John's wort (300 mg t.i.d.), and (iv) at 2 days after cessation of both St John's wort and ritonavir. Combined administration of inducer and inhibitor resulted in a predominance of enzyme inhibition: coadministration of St John's wort and ritonavir with intravenous administration of midazolam resulted in an increase in the area under the plasma concentration-time curve (AUC)(0-8 h) of midazolam to 180% of baseline value, whereas with orally administered midazolam, the AUC(0-6 h) increased to 412% of baseline value (P < 0.05 for each). After cessation of the coadministered drugs, the AUC(0-6 h) of orally administered midazolam decreased to 6% of the level observed during combined administration, and the AUC(0-8 h) of intravenously administered midazolam decreased to 33% of the values observed during combined administration (P < 0.001 for each). Induction may be unmasked after the withdrawal of a combination of a potent CYP3A inhibitor and a potent CYP3A inducer, leading to substantial drops in drug exposure of CYP3A substrates. This may require substantial dose adjustments, particularly of orally administered drugs.

[Information on medications - How do chronically ill patients assess counselling on drugs in general practice?]

BACKGROUND AND OBJECTIVE

Patients with chronic disease have to rely on safe and efficacious drug treatment. They therefore need individual information on their medicaton, in which counselling within the setting of general practice plays a pivotal role. However, information that seems to be relevant from the doctor's point of view is not necessarily consistent with the information patients consider to be necessary. The question was addressed in this study on to what extent patients are satisfied with the information they have received on their medication in general practice?

METHODS

A standardized questionnaire consisting of the SIMS-D (German version of the Satisfaction with Information about Medicines Scale) and MARS-D (German version of the Medication Adherence Report Scale) was sent to 834 chronically ill patients between March 2007 and April 2008.

RESULTS

Patients felt quite satisfied with the information they received on "action and usage" of medication (mean 6.95; range 0 - 9). They were not quite so satisfied with the information they received on "potential problems of medication". Self-reported adherence showed a high mean of 23.6 (range 5 - 25). Less than half of the doctors (43.6 %) inquired "always" or "often" whether patients were taking any other drugs than those prescribed.

CONCLUSION

Patients wish to have more information on potential drug-related problems. More attention needs to be given to a structured review of drugs prescribed in general practice.

[Patient safety based on computer-assisted drug therapy. Electronic check-up of the patient]

Patients in internal medicine frequently experience adverse drug events. Many of those events, however, are avoidable because they are caused by medication errors, which are particularly frequent in drug prescribing. Therefore, practical concepts are needed to make the rapidly growing knowledge on drugs available already during prescription. But also when deviations from standards are intended access to up-to-date information is required. Computer-based systems can offer support for prescribing clinicians to meet these claims and thus improve the quality of pharmacotherapy. To reach this goal, such systems have to be interlinked among each other and with systems of primary, secondary, and tertiary care. They must be based on scientific published evidence and should consider as many factors as possible for individualization of drug therapy. Individualization and focusing on relevant information are prerequisites to prevent inappropriate alerts (over-alerting) and thus to increase acceptance in practical use.

[Medical problems and risks of switching drugs according to legal requirements of drug discount contracts in Germany]

INTRODUCTION

Since 2007 German health insurance funds may conclude discount contracts with pharmaceutical companies for individual drugs. According to German legislation pharmacies are liable to preferentially dispense these drugs to patients of the respective funds if the prescribed drug is identical regarding active ingredient, strength, package size, and route of administration, and is approved for the same indication. We aimed to assess the number and nature of clinically relevant differences between prescribed drug and its legal alternatives.

METHODS

Using databases and expert systems of the drug information system AiD KLINIK we evaluated all 258 412 exchangeable drug pairs of the German market currently regulated by discount contracts.

RESULTS

15,7 % of the drug pairs differed in dosage, in one quarter each colour or shape was significantly different, and in roughly 3 % the size of the substituted drug differed by more than 50 %. In 9,43 % splitting characteristics of solid oral doses differed and in 1,87 % the substituted drug contained additives with allergenic potential not present in the primarily selected drug. On average 0,44 clinically relevant differences could be calculated in each substitution.

CONCLUSION

This study has revealed that current legal provision ignore important medical criteria of the substitution process including individual risks (e. g. allergies). Patients will have to change the drug application process and will therefore need appropriate information and training. All these differences between substitutional drug pairs should already be known when prescribing so as to maintain patient safety in the face of this merely cost-saving measure.

Optimizing information on drug exposure by collection of package code information in questionnaire surveys

PURPOSE

The thorough analysis of special drug characteristics requires information on the specific brand of a drug. This information is often not sought in pharmacoepidemiologic surveys although in many countries packages are labelled with an unequivocal code (in Germany called Pharmazentralnummer (PZN)). We aimed to assess the benefit and quality of PZN information collected in self-completed questionnaires.

METHODS

We performed a survey in 905 ambulatory patients who were asked to list brand name, strength, and the PZN of all drugs they were taking.

RESULTS

The medication list was completed by 97.5% (n = 882) of the responding patients (mean age 67.3 years). Altogether 5543 drugs (100%) were mentioned in the questionnaires and for 4230 (76.3%) the exact drug package could be allocated on the basis of the PZN. When PZN was considered in addition to the drug name the quality of drug coding was significantly improved (p < 0.001) with regard to the allocation of drug package (74% versus 2%), brand (90% versus 70%), and strength (96% versus 86%). The time needed for drug coding was three times shorter.

CONCLUSIONS

The high response rate and high fraction of correct PZN indicate that the collection of package code information is a valuable method to achieve more accurate drug data in questionnaire surveys and to facilitate the drug coding procedure.

Reduction in non-glomerular renal clearance of the caffeine metabolite 1-methylxanthine by probenecid

OBJECTIVE

Urinary caffeine metabolic ratios used to quantify the activity of numerous drug-metabolizing enzymes are an established component of cocktail approaches for metabolic phenotyping. Because in vitro evidence suggests that 1-methylxanthine (1-MX), a major caffeine metabolite, is actively secreted into urine by organic anion transporters (hOATs), coadministration of renal hOAT inhibitors like probenecid may impair these procedures.

METHODS

In a randomized, placebo-controlled, double-blind crossover design, single oral doses of 300 mg caffeine with oral coadministration of placebo or 500 mg probenecid 3 times daily for 2 days were administered to 7 healthy men. The plasma and urine concentrations of caffeine and its major metabolites 1,7-dimethylxanthine (1,7-DMX) and 1-MX were determined by high-performance liquid chromatography.

RESULTS

Coadministration of probenecid resulted in a 34% reduction of the renal clearance of 1-MX (mean +/- SD 190 +/- 42 versus 290 +/- 83 ml min(-1), 95% CI on difference 0.2, 200, p = 0.04) with a 41% reduction in its estimated non-glomerular clearance. The renal clearances of caffeine and 1,7-DMX and the area under the plasma concentration-time curves of all substances were not significantly changed.

CONCLUSIONS

1-MX undergoes renal tubular secretion which is substantially reduced by probenecid, possibly due to inhibition of renal hOATs. This inhibition may explain the influence of probenecid on urinary caffeine metabolic ratios and, thus, its impact on the assessment of enzyme activities. It also suggests that 1-MX might serve as a model substrate for the renal tubular transport of organic anions.

Detection and prevention of prescriptions with excessive doses in electronic prescribing systems

INTRODUCTION

Dose dependent adverse drug reactions are often caused by prescribing errors ignoring upper dose limits. Thus, computerised physician order entry incorporating maximum recommended therapeutic doses (MRTDs) might reduce prescriptions of excessive doses. We evaluated the suitability of MRTD information as published in the Summary of Product Characteristics (SPC) (MRTD(SPC)) or by the US Food and Drug Administration (MRTD(FDA)) and the value of Defined Daily Doses (DDD, World Health Organisation) as knowledge bases for an alerting system.

METHODS

In a large set of critical-dose drugs (N = 140) we compared MRTD(FDA) and DDD values with the corresponding German MRTD(SPC). We then retrospectively assessed a set of 633 electronically prescribed drugs (EPDs) issued at a university hospital and calculated prescription rates of excessive doses.

RESULTS

MRTD(FDA) was similar to MRTD(SPC) in 37% (N = 140), higher in 32%, and lower in 31% of drugs. On average, available DDD values (N = 129) were 1.6 times lower than MRTD(SPC), with 64% being lower, 33% similar, and 3% larger than MRTD(SPC). Prescription rates of excessive doses according to MRTD(FDA) were 2.5-fold higher (6.1%) than according to MRTD(SPC) (2.5%) (p < 0.01). However, only one in four EPDs categorised as overdosed according to MRTD(FDA) exceeded MRTD(SPC), and MRTD(FDA) values were available only for 67% of all assessed EPDs.

CONCLUSION

Our study revealed a remarkable number of prescriptions with doses exceeding approved limits. Their prevention appears feasible but the choice of an appropriate database for MRTDs is essential, and differences between available information sources are large.

CYP3A5 genotype has an impact on the metabolism of the HIV protease inhibitor saquinavir

CYP3A is the main enzyme subfamily involved in the metabolism of the HIV protease-inhibitor saquinavir. We hypothesized that individuals homozygous for CYP3A5*1 might have a higher oral clearance of saquinavir, compared with subjects lacking functional CYP3A5 alleles. A single-dose pharmacokinetic trial of saquinavir soft gel capsules, 1,200 mg, was performed in 16 black Tanzanian healthy volunteers with two functional CYP3A5 alleles (*1/*1) and in 18 volunteers without functional CYP3A5 alleles (both alleles being either *3, *6, or *7). The median area under the plasma concentration-time curve (AUC)0-24 reached among subjects with two functional alleles was 1,410 ng h/ml (interquartile range (IQR) 826-1,929), whereas it was 2,138 ng h/ml (IQR 1,380-3,331) in subjects without (P=0.0533, Mann-Whitney U-test). The median ratio of saquinavir over its M2 plus M3 hydroxy metabolites in urine was 64 (IQR 52-73) in subjects with two functional alleles, whereas it was 145 (IQR 89-181) in those without (P=0.000078, Mann-Whitney U-test). In conclusion, saquinavir is metabolized by CYP3A5. The median AUC0-24 for saquinavir among individuals with two functional CYP3A5 alleles was 34% lower than among those with no functional alleles. To clarify the clinical importance of the CYP3A5 polymorphism, further studies should be conducted on saquinavir, dosed to steady state, in the presence of ritonavir boosting.

Individualisierung der Evidenz – Single Case Randomized Trial

Ein 64-jähriger Patient mit gut eingestellter essentieller Hypertonie berichtet überzeugend vom Therapieerfolg mit Yohimbin in der Akutbehandlung seiner erektilen Dysfunktion. Er wünscht die Verschreibung dieser Substanz, wovon wiederum sein Arzt nicht begeistert ist, da Akuteffekte dieser Behandlung ungewöhnlich sind und die Blockade von α2-adrenergen Rezeptoren den Blutdruck erhöhen kann. Sie einigen sich auf die Objektivierung von Wirksamkeit oder Versagen von Yohimbin in einer experimentellen Untersuchung nach einem Single Case Randomized Trial Design, also einer kontrollierten Versuchsanordnung in einem Einzelpatienten mit doppelblinder Durchführung. Der zehnmalige Vergleich von Placebo und oralem Yohimbin ließ keinen Unterschied erkennen und verhinderte, dass der Patient mit einer potenziell schädlichen Arzneimittel-Kombination exponiert wurde.

The frequency of inappropriate tablet splitting in primary care

INTRODUCTION

We assessed the frequency and determinants of tablet splitting in primary care in Germany and evaluated the quality of information on divisibility in the Summary of Product Characteristics (SPCs) and in the Package Leaflet (PL) as legal sources of information for health care providers and patients.

METHODS

We performed a cross-sectional questionnaire survey among patients of 59 general practitioners in the German Federal State Saxony-Anhalt in 2005 in order to collect detailed information on all drugs of patients maintained on more than three drugs.

RESULTS

The response rate was 82.1% (n=905) and 3,158 drugs (tablets and dragées) were included in the analyses. Of all drugs, 24.1% were split (762 of 3,158): 8.7% of all split tablets were unscored (66 of 762) and 3.8% of all split tablets were not allowed to be split (29 of 762). Tablets of the higher price categories and higher strengths were twice as likely to be split. Only 22.5% of the SPCs (9 of 40) of the split unscored tablet brands contained explicit information on divisibility and only 36.4% of the PLs (8 of 22) of the split brands that were not allowed to be split stated that splitting was not appropriate.

CONCLUSION

The splitting of tablets in primary care is a frequent habit likely driven by medical and economic considerations. Almost 1% of all tablets are split that must not be fragmented. However, the SPC and PL provide only limited information on divisibility stressing the need to improve this information promptly to avoid medication errors.

[Drug administration errors--what information is required to enable patients to safely take their drugs?]

More than 100 different routes of drug administration are known for which highly specialised galenic formulations and sophisticated containers and application devices have been developed. Consequently substantial knowledge is required to use them in a proper and most successful way. The trend of moving the responsibility for drug application to patients and care givers necessitates their appropriate and comprehensive information to enable them to administer medication safely, skilfully, and correctly. This also includes practical skills for instance to open blisters and containers, to split tablets when needed, and to inhale, inject, or ingest the drugs. This article compiles the areas of information which should be covered, communicated, and checked by the prescribing physician and the dispensing pharmacist to maximise the patients' odds for a successful therapy.

Tabletten teilen

Knapp ein Drittel der ambulanten Patienten teilen ihre Tabletten vor der Einnahme. Diese gängige Praxis birgt, neben etlichen Vorteilen, allerdings auch einige Risiken für die Arzneimitteltherapie. Vor allem ältere Patienten sind häufig nicht in der Lage Tabletten exakt zu teilen und die unsachgemäße Teilung z.B. von Retardpräparaten kann zu einer Überdosierung führen. Ob eine Tablette geteilt werden darf, hängt im Wesentlichen von den Wirkstoffeigenschaften, der Galenik, der Form der Tablette und der Beschaffenheit der Bruchkerbe ab. Darüber hinaus muss gesichert sein, dass der Patient über die erforderliche Bereitschaft und Fingergeschicklichkeit verfügt, seine Tabletten zu teilen, um die Compliance nicht zu beeinträchtigen. Nicht zuletzt muss der Patient über die richtige Teilungstechnik informiert sein, damit beim Teilen zwei gleichgroße Bruchstücke entstehen und die Wirksamkeit der Therapie nicht gefährdet wird.

Arzneimittel in Schwangerschaft und Stillzeit

BACKGROUND AND OBJECTIVE

In selecting drugs for treatment during pregnancy and breastfeeding it is essential to be certain of their safety. But categories are lacking that systematically relate the current state of knowledge of individual substances--rather than just drug classes--to each trimester of pregnancy. As such a stratification of risk would be helpful, it was the aim of this study to propose a new and more differentiated classification.

METHODS

Internationally available literature and electronic data bases providing details on adverse effects of individual drugs during pregnancy and breastfeeding as well as summaries of product characteristics of the drugs served as comprehensive sources of information. Account was taken of compound-specific data on toxicity during the reproductive and developmental stages, genotoxicity and carcinogenicity (in animals and in-vitro experiments) and drug-specific experience as documented in women during pregnancy and breastfeeding.

RESULTS

A new risk classification and appropriate recommendations for clinical management were developed to ensure the safety of drugs given during pregnancy and breastfeeding, taking into account the varying risks during the three trimesters of pregnancy and the perinatal period. Antibiotics were selected as a model for drugs in general and classified according to the new system.

CONCLUSION

The proposed new classification of risk makes it possible to select safe agents in the treatment of pregnant and/or breastfeeding women. It is based on the current state of knowledge about a particular substance, also in relationship to the developmental phase of the breastfed child.

Standardized documentation of drug recommendations in discharge letters--a contribution to quality management in cooperative care

OBJECTIVES

To analyze the necessity and potential usefulness of a computerized physician order entry (CPOE) system in supporting the writing of pharmacotherapeutic recommendations in discharge letters.

METHODS

Systematic analysis of drug recommendations in discharge letters of a hospital providing tertiary care, structured interviews with in-hospital prescribers, and focus groups with general practitioners who admit patients to this hospital.

RESULTS

We analyzed 1800 randomly selected discharge letters, 1205 of which contained pharmacotherapeutic recommendations. The frequencies, structure, and quality of these recommendations varied considerably between departments. Nearly 16% of the recommendations contained both proprietary (brand) and non-proprietary names (active ingredient). Interviewed clinicians expressed interest in CPOE systems that check for contraindications and interactions between drugs, suggest cheaper products, and automatically insert active ingredients when omitted. The focus group sessions confirmed that the pharmacotherapeutic recommendations in current discharge letters do not effectively support daily clinical practice.

CONCLUSIONS

Documenting active ingredients as well as brand names in drug therapy recommendations is currently not part of clinical practice. Computerized decision support can help to optimise the structure and communication of therapeutic information across interfaces and can be a quality factor with considerable influence on process quality, outcome quality, and costs of cooperative patient care.