Misdiagnosis and mistreatment of a common side-effect--angiotensin-converting enzyme inhibitor-induced cough

Prescription Sequence Symmetry Analysis (PSSA) to assess prescribing cascades: a step-by-step guide

Prescribing cascades occur when patients are prescribed medication to treat the adverse drug reaction of previously prescribed medication. Prescription sequence symmetry analysis (PSSA) can be used to assess the association between two medications in prescription or dispensing databases and thus the potential occurrence of prescribing cascades. In this article, a step-by-step guide is presented for conducting PSSA to assess prescribing cascades. We describe considerations for medication data collection and setting time periods for relevant parameters, including washout window, exposure window, continued exposure interval and blackout period. With two examples, we illustrate the impact of changes in these parameters on the strengths of associations observed. Given the impact seen, we recommend that researchers clearly specify and explain all considerations regarding medication included and time windows set when studying prescribing cascades with PSSA, and conduct subgroup and sensitivity analyses.

Prescribing cascades in ambulatory care: A structured synthesis of evidence

The strength of evidence for specific ambulatory care prescribing cascades, in which a marker drug is used to treat an adverse event caused by an index drug, has not been well characterized. To perform a structured, systematic, and transparent review of the evidence supporting ambulatory care prescribing cascades. Ninety-four potential prescribing cascades identified through a previously published systematic review. Systematic search of the literature to further characterize prescribing cascades. (1) Grading of evidence based on observational studies investigating associations between index and marker drugs, including: Level I-strong evidence [i.e. multiple high-quality studies]; Level II-moderate evidence [i.e. single high-quality study]; Level III-fair evidence [no high-quality studies but one or more moderate-quality studies]; and Level IV-poor evidence [other]. (2) Listing of the adverse event associated with the index drug in the product's United States Food and Drug Administration (FDA) label. (3) Synthesis of the evidence supporting mechanisms linking index drugs and associated adverse events. Of 99 potential cascades, 94 were supported by one or more confirmatory observational studies and were therefore included in this review. The 94 cascades related to 30 types of adverse drug reactions affecting 10 different anatomic/physiologic systems and were investigated by a total of 88 confirmatory studies, including prescription sequential symmetry analysis (n = 51), cohort (n = 30), and case-control (n = 7) studies. Overall, the evidence from observational studies was strong for 18 (19.1%) prescribing cascades, moderate for 61 (64.9%), fair for 13 (13.8%), and poor for 2 (2.1%). Although the evidence supporting mechanisms that link index drugs and associated adverse events was variable, FDA labels included information about the adverse event associated with the index drug for most (n = 86) but not all of the 94 prescribing cascades. Although we identified 18 of 94 prescribing cascades supported by strong clinical evidence and most adverse events associated with index drugs are included in FDA label, the evidentiary basis for prescribing cascades varies, with many requiring further evidence of clinical relevance.

Prescribing Cascades with Recommendations to Prevent or Reverse Them: A Systematic Review

BACKGROUND

To reduce prescribing cascades occurring in clinical practice, healthcare providers require information on the prescribing cascades they can recognize and prevent.

OBJECTIVE

This systematic review aims to provide an overview of prescribing cascades, including dose-dependency information and recommendations that healthcare providers can use to prevent or reverse them.

METHODS

The Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) was followed. Relevant literature was identified through searches in OVID MEDLINE, OVID Embase, OVID CINAHL, and Cochrane. Additionally, Web of Science and Scopus were consulted to analyze reference lists and citations. Publications in English were included if they analyzed the occurrence of prescribing cascades. Prescribing cascades were included if at least one study demonstrated a significant association and were excluded when the adverse drug reaction could not be confirmed in the Summary of Product Characteristics. Two reviewers independently extracted and grouped similar prescribing cascades. Descriptive summaries were provided regarding dose-dependency analyses and recommendations to prevent or reverse these prescribing cascades.

RESULTS

A total of 95 publications were included, resulting in 115 prescribing cascades with confirmed adverse drug reactions for which at least one significant association was found. For 52 of these prescribing cascades, information regarding dose dependency or recommendations to prevent or reverse prescribing cascades was found. Dose dependency was analyzed and confirmed for 12 prescribing cascades. For example, antipsychotics that may cause extrapyramidal syndrome followed by anti-parkinson drugs. Recommendations focused on dosage lowering, discontinuing medication, and medication switching. Explicit recommendations regarding alternative options were given for three prescribing cascades. One example was switching to ondansetron or granisetron when extrapyramidal syndrome is experienced using metoclopramide.

CONCLUSIONS

In total, 115 prescribing cascades were identified and an overview of 52 of them was generated for which recommendations to prevent or reverse them were provided. Nonetheless, information regarding alternative options for managing prescribing cascades was scarce.

Research on prescribing cascades: a scoping review

Background: The concept of prescribing cascades has been proposed for more than 20 years, but the research progress and cognitive level varied in different countries. The aim of this study was to systematically evaluate the current status of relevant original research on prescribing cascades, and to provide references for further research and continuous improvement in clinical practice. Methods: We searched three English databases and four Chinese databases from inception until January 2022. Relevant studies about prescribing cascades meeting the eligibility criteria were extracted independently by two reviewers, and a descriptive analysis was conducted to compare the methods and outcomes of the included studies. Results: A total of 32 studies involving 7,075,200 patients in 11 countries were included, including 13 cross-sectional studies, 11 case reports, 7 cohort studies, and 1 case-control study. The target population was mainly elderly people (24 studies). The purpose of the included studies could be divided into three categories: prevention (4 studies), identification (17 studies), and resolution (11 studies) of prescribing cascades. 49 prescribing cascade routes were identified and mainly attributed to the cardiovascular system, most primary diseases of which were dementia, the initial medications of prescribing cascades were mainly calcium channel blockers, and two to six drugs were involved in the prescribing cascade routes. Conclusion: Prescribing cascades have attracted more attention internationally and current studies have mainly focused on the elderly and their cardiovascular diseases and nervous diseases, but still not yet formed integral research in other special populations of drug use, such as children and pregnant women. It is necessary to further conduct in-depth studies with a broader range, and to establish a series of effective measures to decrease the incidence of prescribing cascades in the high-risk group of drug use.

Prescribing cascades in community-dwelling adults: A systematic review

The misattribution of an adverse drug reaction (ADR) as a symptom or illness can lead to the prescribing of additional medication, referred to as a prescribing cascade. The aim of this systematic review is to identify published prescribing cascades in community-dwelling adults. A systematic review was reported in line with the PRISMA guidelines and pre-registered with PROSPERO. Electronic databases (Medline [Ovid], EMBASE, PsycINFO, CINAHL, Cochrane Library) and grey literature sources were searched. Inclusion criteria: community-dwelling adults; risk-prescription medication; outcomes-initiation of new medicine to "treat" or reduce ADR risk; study type-cohort, cross-sectional, case-control, and case-series studies. Title/abstract screening, full-text screening, data extraction, and methodological quality assessment were conducted independently in duplicate. A narrative synthesis was conducted. A total of 101 studies (reported in 103 publications) were included. Study sample sizes ranged from 126 to 11 593 989 participants and 15 studies examined older adults specifically (≥60 years). Seventy-eight of 101 studies reported a potential prescribing cascade including calcium channel blockers to loop diuretic (n = 5), amiodarone to levothyroxine (n = 5), inhaled corticosteroid to topical antifungal (n = 4), antipsychotic to anti-Parkinson drug (n = 4), and acetylcholinesterase inhibitor to urinary incontinence drugs (n = 4). Identified prescribing cascades occurred within three months to one year following initial medication. Methodological quality varied across included studies. Prescribing cascades occur for a broad range of medications. ADRs should be included in the differential diagnosis for patients presenting with new symptoms, particularly older adults and those who started a new medication in the preceding 12 months.

Hypertension: Constraining the Expression of ACE-II by Adopting Optimal Macronutrients Diet Predicted via Support Vector Machine

The recent elevation of cases infected from novel COVID-19 has placed the human life in trepidation mode, especially for those suffering from comorbidities. Most of the studies in the last few months have undeniably raised concerns for hypertensive patients that face greater risk of fatality from COVID-19. Furthermore, one of the recent WHO reports has estimated a total of 1.13 billion people are at a risk of hypertension of which two-thirds live in low and middle income countries. The gradual escalation of the hypertension problem andthe sudden rise of COVID-19 cases have placed an increasingly higher number of human lives at risk in low and middle income countries. To lower the risk of hypertension, most physicians recommend drugs that have angiotensin-converting enzyme (ACE) inhibitors. However, prolonged use of such drugs is not recommended due to metabolic risks and the increase in the expression of ACE-II which could facilitate COVID-19 infection. In contrast, the intake of optimal macronutrients is one of the possible alternatives to naturally control hypertension. In the present study, a nontrivial feature selection and machine learning algorithm is adopted to intelligently predict the food-derived antihypertensive peptide. The proposed idea of the paper lies in reducing the computational power while retaining the performance of the support vector machine (SVM) by estimating the dominant pattern in the features space through feature filtering. The proposed feature filtering algorithm has reported a trade-off performance by reducing the chances of Type I error, which is desirable when recommending a dietary food to patients suffering from hypertension. The maximum achievable accuracy of the best performing SVM models through feature selection are 86.17% and 85.61%, respectively.

Evaluation of a Beta-Blocker-Edema-Loop Diuretic Prescribing Cascade: A Prescription Sequence Symmetry Analysis

BACKGROUND

Drug-related adverse events associated with antihypertensive therapy may result in subsequent prescribing of other potentially harmful medications, known as prescribing cascades. The aim of this study was to assess the magnitude and characteristics of a beta-blocker-edema-loop diuretic prescribing cascade.

METHODS

A prescription sequence symmetry analysis was used to assess loop diuretic initiation before and after initiation of beta-blockers among patients 20 years or older without heart failure, atrial fibrillation, other arrythmias, or use of calcium channel blocker within a U.S. private insurance claims database (2005-2018). The temporality of loop diuretic initiation relative to a beta-blocker or negative control (renin-angiotensin system blocker) initiation was tabulated. Secular trend-adjusted sequence ratios (aSRs) with 95% confidence intervals (CIs) compared the initiation of loop diuretic 90 days before and after initiation of beta-blockers.

RESULTS

Among 988,675 beta-blocker initiators, 9,489 patients initiated a new loop diuretic prescription 90 days after and 5,245 patients before beta-blocker initiation, resulting in an aSR of 1.78 (95% CI, 1.72-1.84). An estimated 1.72 beta-blocker initiators per 100 patient-years experienced the prescribing cascade in the first 90 days. The aSR was disproportionately higher among older adults (aSR 1.97), men (aSR 2.25), and patients who initiated metoprolol tartrate (aSR 2.48), labetalol (aSR 2.18), or metoprolol succinate (aSR 2.11). Negative control results (aSR 1.09, 95% CI, 1.05-1.13) generally corroborated our findings, but suggested modest within-person time-varying confounding.

CONCLUSIONS

We observed excess use of loop diuretics following beta-blocker initiation that was only partially explained by secular trends or hypertension progression.

Evaluation of the key prescription sequence symmetry analysis assumption using the calcium channel blocker: Loop diuretic prescribing cascade

OBJECTIVES

To evaluate the prescription sequence symmetry analysis assumption regarding balance between marker drug (i.e., medication used to treat a drug-induced adverse event) initiation rates before and after initiation of an index drug (i.e., medication that is potentially associated with the drug-induced adverse event) in the absence of prescribing cascades, we used a well-described example of loop diuretic initiation to treat dihydropyridine calcium channel blockers (DH CCB)-induced edema.

STUDY DESIGN AND SETTING

The University of Florida Health Integrated Data Repository from June 2011 and July 2018 was used to assess temporal prescribing of DH CCB and loop diuretics within the prescription sequence symmetry analysis framework. Validation of the prescribing cascade was performed via clinical expert chart review.

RESULTS

Among patients without heart failure who were initiated on DH CCB, 26 and 64 loop diuretics initiators started within 360 days before versus after DH CCB initiation, respectively, resulting in an adjusted sequence ratio (aSR) of 2.27 (95% CI, 1.44-3.58). Overall, 35 (54.7%) patients were determined to have a prescribing cascade. Removing patients who experienced a prescribing cascade resulted in an aSR of 1.05, 95% CI 0.62-1.78).

CONCLUSION

Loop diuretic initiation rates before and after DH CCB initiation for reasons other a prescribing cascade were similar, thus confirming the prescription sequence symmetry analysis assumption.

Anti-hypertensive Peptide Predictor: A Machine Learning-Empowered Web Server for Prediction of Food-Derived Peptides with Potential Angiotensin-Converting Enzyme-I Inhibitory Activity

Angiotensin converting enzyme-I (ACE-I) is a key therapeutic target of the renin-angiotensin-aldosterone system (RAAS), the central pathway of blood pressure regulation. Food-derived peptides with ACE-I inhibitory activities are receiving significant research attention. However, identification of ACE-I inhibitory peptides from different food proteins is a labor-intensive, lengthy, and expensive process. For successful identification of potential ACE-I inhibitory peptides from food sources, a machine learning and structural bioinformatics-based web server has been developed and reported in this study. The web server can take input in the FASTA format or through UniProt ID to perform the in silico gastrointestinal digestion and then screen the resulting peptides for ACE-I inhibitory activity. This unique platform provides elaborated structural and functional features of the active peptides and their interaction with ACE-I. Thus, it can potentially enhance the efficacy and reduce the time and cost in identifying and characterizing novel ACE-I inhibitory peptides from food proteins. URL: http://hazralab.iitr.ac.in/ahpp/index.php.

Evaluating the use of prescription sequence symmetry analysis as a pharmacovigilance tool: A scoping review

BACKGROUND

The (prescription) sequence symmetry analysis (PSSA) design has been used to identify potential prescribing cascade signals by assessing the prescribing sequence of an index drug relative to a marker drug presumed to treat an adverse drug event provoked by the index drug.

OBJECTIVES

This review aimed to explore the use of the PSSA design as a pharmacovigilance tool with a particular focus on the breadth of identified signals and advances in PSSA methodology.

METHODS

We searched Embase, PubMed/Medline, Google Scholar, Web of Science and grey literature to identify studies that used the PSSA methodology. Two reviewers independently extracted relevant data for each included article. Study characteristics including signals identified, exposure time window, stratified analyses, and use of controls were extracted.

RESULTS

We identified 53 studies which reported original results obtained using PSSA methodology or quantified the validity of components of the PSSA design. Of those, nine studies provided validation metrics showing reasonable sensitivity and high specificity of PSSA to identify prescribing cascade signals. We identified 340 unique index drug - marker drug signals published in the PSSA literature, representing 281 unique index - marker pharmacological class dyads (i.e., unique fourth-level Anatomical Therapeutic Chemical [ATC] classification dyads). Commonly observed signals were identified for index drugs acting upon the nervous system (34%), cardiovascular system (21%), and blood and blood-forming organs (15%), and many marker drugs were related to the nervous system (25%), alimentary tract and metabolism (23%), cardiovascular system (17%), and genitourinary system and sex hormones (14%). Negative controls and positive controls were utilized in 21% and 13% of studies, respectively.

CONCLUSIONS

The PSSA methodology has been used in 53 studies worldwide to detect and evaluate over 300 unique prescribing cascades signals. Researchers should consider sensitivity analyses incorporating negative and/or positive controls and additional time windows to evaluate time-varying biases when designing PSSA studies.

Detecting Suspected Prescribing Cascades by Prescription Sequence Symmetry Analysis of Nationwide Real-World Data

OBJECTIVE

A prescription cascade is a subsequent event that occurs when an adverse drug event is misinterpreted as a new medical condition, resulting in the prescription of a potentially unnecessary medication to treat this new condition. This study was designed to test the hypothesis of whether prescribing cascades exist and their magnitude among older individuals by using prescription sequence symmetry analysis (PSSA).

DESIGN

A retrospective population-based cohort study based on data from Taiwan's National Health Insurance Research Database (NHIRD), a nationwide claims-based database that covers 99% of the population in Taiwan.

SETTING AND PARTICIPANTS

Patients receiving newly initiated index and marker drugs in the outpatient setting between 2014 and 2016 were included. Those who received index and marker drugs on the same date were excluded.

MEASURES

PSSA measures the propensity for a marker drug (eg, thyroxine) to be prescribed after an index drug (eg, amiodarone) has been initiated, where the index drug is suspected of inducing a side effect (eg, hypothyroidism) and the marker drug is used to treat the side effect. We evaluated 14 PSSA sets as potential prescription cascade-related drug pairs (index and marker drug), including 2 confirmatory analyses (eg, amiodarone and thyroxin), to check the validity of the PSSA results and 12 exploratory analyses of cardiovascular medication-related prescribing cascades (eg, statins and antidepressants). The observation periods for sequences of incident marker drug use were 1 year before and 1 year after the use of the incident index drug, and the symmetry of prescriptions filled for the 2 periods was examined. The results of the PSSA were performed as the crude sequence ratio (SR), defined as the ratio of patients initiating the marker drug after the index drug (causal group) to those initiating the marker drug before the index drug (noncausal group), and the adjusted SR (aSR) with 95% confidence intervals (CIs).

RESULTS

Among 12 potential prescription cascade-related drug pairs in exploratory analysis, 9 of them reached statistical significance, and aSR ranged from 1.02 to 1.46. Dihydropyridine calcium channel blocker-induced edema showed the highest aSR (1.46, 95% CI 1.45-1.48), and statin-induced muscle pain showed the lowest aSR (1.02, 95% CI 1.02-1.03).

CONCLUSIONS AND IMPLICATIONS

Our study supported the application of PSSA in detecting prescribing cascades using a nationwide claims database. Nevertheless, most previously reported prescribing cascades among cardiovascular medications were shown to have a low effect size of sequence ratios among older individuals.

Magnitude of and Characteristics Associated With the Treatment of Calcium Channel Blocker-Induced Lower-Extremity Edema With Loop Diuretics

IMPORTANCE

Calcium channel blockers, specifically dihydropyridine calcium channel blockers (DH CCBs, eg, amlodipine), may cause lower-extremity edema. Anecdotal reports suggest this may result in a prescribing cascade, where DH CCB-induced edema is treated with loop diuretics.

OBJECTIVE

To assess the magnitude and characteristics of the DH CCB prescribing cascade.

DESIGN, SETTING, AND PARTICIPANTS

This cohort study used a prescription sequence symmetry analysis to assess loop diuretic initiation before and after the initiation of DH CCBs among patients aged 20 years or older without heart failure. Data from a private insurance claims database from 2005 to 2017 was analyzed. Use of loop diuretics associated with initiation of angiotensin-converting enzyme inhibitors, angiotensin receptor blockers, and other commonly used medications was used as negative controls. Data were analyzed from March 2019 through October 2019.

EXPOSURES

Initiation of DH CCB or negative control medications.

MAIN OUTCOMES AND MEASURES

The temporality of loop diuretic initiation relative to DH CCB or negative control initiation. Secular trend-adjusted sequence ratios (aSRs) with 95% CIs were calculated using data from 360 days before and after initiation of DH CCBs.

RESULTS

Among 1 206 093 DH CCB initiators, 55 818 patients (4.6%) (33 100 [59.3%] aged <65 years; 32 916 [59.0%] women) had a new loop diuretic prescription 360 days before or after DH CCB initiation, resulting in an aSR of 1.87 (95% CI, 1.84-1.90). An estimated 1.44% of DH CCB initiators experienced the prescribing cascade. The aSR was disproportionately higher among DH CCB initiators who were prescribed high doses (aSR, 2.20; 95% CI, 2.13-2.27), initiated amlodipine (aSR, 1.89; 95% CI, 1.86-1.93), were men (aSR, 1.96; 95% CI, 1.91-2.01), and used fewer antihypertensive classes (aSR, 2.55; 95% CI, 2.47-2.64). The evaluation of ACE inhibitors or ARBs as negative controls suggested hypertension progression may have tempered the incidence of the prescribing cascade (aSR for ACE inhibitors and ARBs, 1.27; 95% CI, 1.24-1.29).

CONCLUSIONS AND RELEVANCE

This study found an excessive use of loop diuretics following initiation of DH CCBs that cannot be completely explained by secular trends or hypertension progression. The prescribing cascade was more pronounced among those initially prescribed a high dose of DH CCBs.

Prescribing issues in elderly individuals living with HIV

Introduction: Combined antiretroviral therapy has transformed HIV infection into a chronic disease thus people living with HIV (PLWH) live longer. As a result, the management of HIV infection is becoming more challenging as elderly experience age-related comorbidities leading to complex polypharmacy and a higher risk for drug-drug or drug-disease interactions. Furthermore, age-related physiological changes affect pharmacokinetics and pharmacodynamics thereby predisposing elderly PLWH to incorrect dosing or inappropriate prescribing and consequently to adverse drug reactions and the subsequent risk of starting a prescribing cascade. Areas covered: This review discusses the demographics of the aging HIV population, physiological changes and their impact on drug response as well as comorbidities. Particular emphasis is placed on common prescribing issues in elderly PLWH including drug-drug interactions with antiretroviral drugs. A PubMed search was used to compile relevant publications until February 2019. Expert opinion: Prescribing issues are highly prevalent in elderly PLWH thus highlighting the need for education on geriatric prescribing principles. Adverse health outcomes potentially associated with polypharmacy and inappropriate prescribing should promote interventions to prevent harm including medication reconciliation, medication review, and medication prioritization according to the risks/benefits for a given patient. A multidisciplinary team approach is recommended for the care of elderly PLWH.

The provision of advice by pharmacy staff in eastern Indonesian community pharmacies

Background:

Indonesian community pharmacies hold a strategic position from which to promote the rational use of medicines by providing appropriate advice for patients requesting self-medication. To date, published studies related to the provision of advice in Indonesian community pharmacies are limited and have been conducted only in more developed western Indonesia. No studies have been undertaken in eastern Indonesia, which is less developed than and culturally different from the western region.

Objectives:

This paper aims to: (1) describe the types and amount of advice provided by pharmacy staff for three scenarios in a patient simulation study and for two scenarios in pharmacy staff interviews; and (2) ascertain the frequency of appropriate advice given in response to the scenarios.

Methods:

A patient simulation study was conducted at community pharmacies in an eastern Indonesian provincial capital. Four weeks after completing a patient simulation study, structured interviews with pharmacy staff were conducted. Two cough scenarios and one diarrhoea scenario were developed for the patient simulation study. Meanwhile, two scenarios (an ACE inhibitor-induced cough and a common cough and cold) were developed for pharmacy staff interviews. The types and amount of advice provided by pharmacy staff were recorded on paper and assessed for its appropriateness. The determination of appropriate advice was based on the literature and by consensus of two Indonesian experts.

Results:

In patient simulation, the most common type of advice provided in all scenarios was product recommendations. In interviews, medical referrals and recommending cough and cold medicine were the most common types of advice provided for ACE inhibitor-induced cough and common cough and cold scenarios respectively. Appropriate advice was provided in less than 0.5% in the patient simulation study, but two-third of participants in the interviews responded to the scenarios appropriately.

Conclusions:

Pharmacy staff did not provide appropriate advice in practice, although they may have adequate knowledge. A contributing factor was insufficient information gathered in patient encounters. Optimising information-gathering practice by pharmacy staff is needed.

Physicians' role in the development of inappropriate polypharmacy among older adults in Iran: a qualitative study

OBJECTIVES

The use of unnecessary or excessive medications (inappropriate polypharmacy) is a major health challenge among older adults which is driven by several factors. This study aims to provide in-depth descriptions of the physician's role in the development of inappropriate polypharmacy among older adults in Iran.

DESIGN

Qualitative content analysis of interviews, field notes and other relevant documents available (eg, medical records). Data collection and analyses were done concurrently to guide the sampling process.

SETTING

Three purposively selected referral hospitals in Tehran, Iran.

PARTICIPANTS

A total of 7 physicians, 10 older adults, 3 caregivers and 3 pharmacists with a median age of 54 (IQR 23) years were recruited through convenience sampling.

RESULTS

Emerged categories included misdiagnosis, inappropriate prescribing, insufficient patient education, poor communication, unprofessional behaviour and limited perspectives which highlight the role of physicians in the development of inappropriate polypharmacy among older adults in Iran under the main concept of poor medical practice.

CONCLUSION

This study provides valuable insight on the role of physicians in the development of inappropriate polypharmacy among the elderly in the healthcare setting in Iran by exploring the viewpoints of physicians, patients, caregivers and pharmacists. Physicians can be an influential factor in tackling this challenge through proper diagnosis, prescription, patient education and follow-up. In Iran, physicians' practice styles are affected by potentially adverse factors such as the novelty of geriatric medicine, lack of a referral system, patient unfamiliarity with the system and lack of a monitoring system for multiple prescriptions. Furthermore, clinics tend to be overcrowded and visit fees can be low; in this setting, lack of physician assistants leads to limited time allocation to each patient and physician dissatisfaction with their income.

Effect estimate comparison between the prescription sequence symmetry analysis (PSSA) and parallel group study designs: A systematic review

Prescription sequence symmetry analysis (PSSA), a case-only design introduced in 1996, has been increasingly used to identify unintentional drug effects, and has potential applications as a hypothesis-testing and a hypothesis-generating method, due to its easy application and effective control of time-invariant confounders. The aim of this study is to systematically compare effect estimates from the PSSA to effect estimates from conventional observational parallel group study designs, to assess the validity and constraints of the PSSA study design. We reviewed the MEDLINE, EMBASE, and Web of Science databases until February 2016 to identify studies that compared PSSA to a parallel group design. Data from the eligible articles was extracted and analyzed, including making a Bland-Altman plot and calculating the number of discrepancies between the designs. 63 comparisons (from two studies) were included in the review. There was a significant correlation (p < 0.001) between the effect estimates of the PSSA and the parallel group designs, but the bias indicated by the Bland-Altman plot (0.20) and the percentage of discrepancies (70–80%) showed that this correlation was not accompanied by a considerable similarity of the effect estimates. Overall, the effect estimates of the parallel group designs were higher than those of the PSSA, not necessarily further away from 1, and the parallel group designs also generated more significant signals. However, these results should be approached with caution, as the effect estimates were only retrieved from two separate studies. This review indicates that, even though PSSA has a lot of potential, the effect estimates generated by the PSSA are usually lower than the effect estimates generated by parallel group designs, and PSSA mostly has a lower power than the conventional study designs, but this is based on limited comparisons, and more comparisons are needed to make a proper conclusion.

Assessment of Medication Safety Using Only Dispensing Data

PURPOSE OF REVIEW

The purpose of this review is to provide an overview of the published studies that have been used to generate evidence on the safety of medicine use when only medication dispensing data are available.

RECENT FINDINGS

Medication dispensing databases are increasingly available for research on large populations, particularly in countries that provide universal coverage for medicines. These data are often used for drug utilisation studies to identify inappropriate medicine use at the population level that may be associated with known safety issues. Lack of coded diagnoses, to identify outcomes, and lack of data on confounders can limit use of these data in practice for medication safety assessment. To overcome these issues, studies have exploited the fact that symptoms of adverse effects of medications can be treated with other medications, for example antidepressants to treat depression or oxybutynin to treat urinary incontinence. The challenge of unmeasured confounding has been addressed by implementing self-controlled study designs that use within-person comparisons and provide inherent control for confounding. Prescription sequence symmetry analysis (SSA) is a within-person study design that has been demonstrated as a useful tool for safety signal generation in dispensing data.

SUMMARY

Using medicine initiation as a proxy for the development of adverse events can help to generate evidence of the safety of medicines when only medication dispensing data are available. Careful consideration, however, should be given to the sensitivity and specificity of the proxy medicine for the adverse event and potential for time-varying confounding due to trends in medicine utilisation. Data-mining approaches using dispensing data have the potential to improve safety assessments; however, the challenge of unmeasured confounding with these methods remains to be investigated.

Clinical Efficacy and Safety of Xinmailong Injection for the Treatment of Chronic Heart Failure: A Meta-Analysis

Background: Chronic heart failure (CHF) is one of the most stubborn cardiovascular disease. Xinmailong (XML), a bioactive fraction extracted from Periplaneta americana L., has been commonly used for CHF treatment in China. However, there is few comprehensive evaluation for the clinical efficacy and safety of XML for CHF. Objectives: We aimed to evaluate the beneficial and adverse effects of Xinmailong Injection (XMLI) on CHF treatment with the use of meta-analysis. Methods: In accordance with the Cochrane Handbook and transparent reporting of systematic reviews and meta-analysis protocol (CRD42018087091), seven English and Chinese electronic databases, including PubMed, EMBASE, Cochrane Library, Chinese National Knowledge Infrastructure (CNKI), Wanfang database, VIP medicine information system and China Biomedical Literature Database (CBM), were searched to retrieve potential randomized controlled trials (RCTs) before November 2017. The eligible trials were evaluated for methodological quality. The main outcome measures were analyzed with RevMan 5.3 software. Results: 26 RCTs involving 3447 participants were subjected to meta-analysis. The total effective rate was improved by XMLI plus conventional therapy (OR 3.10, 95% CI 2.47-3.90, P < 0.00001). When compared to the conventional treatment alone, the combination of XMLI and conventional treatment increased left ventricular ejection fraction (LVEF, MD 4.93, 95% CI 3.96-5.89, P < 0.00001) and 6-min walking distance (6-MWD, MD 46.76, 95% CI 32.51 to 61.01, P < 0.00001), and decreased left ventricular end-diastolic diameter (LVEDD, MD -4.73, 95% CI-5.64 to-3.83, P < 0.00001), serum brain natriuretic peptide (BNP, MD -149.59, 95% CI -211.31 to -87.88, P < 0.00001) and N-terminal pro-brain natriuretic peptide (NT-proBNP, MD -322.35, 95% CI -517.87 to -126.83, P = 0.001). However, the frequency and severity of adverse effects was similar between these two different medications. Poor methodological quality and the limitations also existed in this study. Conclusions: The combinational use of XMLI on conventional treatment may exert better therapeutic effects on improving cardiac function in CHF patients, indicating that XMLI was suggested to be considered during the conventional treatment of CHF. High-quality and large scale RCTs are still required to confirm the impacts of XMLI.

Supervised signal detection for adverse drug reactions in medication dispensing data

MOTIVATION

Adverse drug reactions (ADRs) are one of the leading causes of morbidity and mortality and thus should be detected early to reduce consequences on health outcomes. Medication dispensing data are comprehensive sources of information about medicine uses that can be utilized for the signal detection of ADRs. Sequence symmetry analysis (SSA) has been employed in previous studies to detect signals of ADRs from medication dispensing data, but it has a moderate sensitivity and tends to miss some ADR signals. With successful applications in various areas, supervised machine learning (SML) methods are promising in detecting ADR signals. Gold standards of known ADRs and non- ADRs from previous studies create opportunities to take into account additional domain knowledge to improve ADR signal detection with SML.

OBJECTIVE

We assess the utility of SML as a signal detection tool for ADRs in medication dispensing data with the consideration of domain knowledge from DrugBank and MedDRA. We compare the best performing SML method with SSA.

METHODS

We model the ADR signal detection problem as a supervised machine learning problem by linking medication dispensing data with domain knowledge bases. Suspected ADR signals are extracted from the Australian Pharmaceutical Benefit Scheme (PBS) medication dispensing data from 2013 to 2016. We construct predictive features for each signal candidate based on its occurrences in medication dispensing data as well as its pharmacological properties. Pharmaceutical knowledge bases including DrugBank and MedDRA are employed to provide pharmacological features for a signal candidate. Given a gold standard of known ADRs and non-ADRs, SML learns to differentiate between known ADRs and non-ADRs based on their combined predictive features from linked sources, and then predicts whether a new case is a potential ADR signal.

RESULTS

We evaluate the performance of six widely used SML methods with two gold standards of known ADRs and non-ADRs from previous studies. On average, gradient boosting classifier achieves the sensitivity of 77%, specificity of 81%, positive predictive value of 76%, negative predictive value of 82%, area under precision-recall curve of 81%, and area under receiver operating characteristic curve of 82%, most of which are higher than in other SML methods. In particular, gradient boosting classifier has 21% higher sensitivity than and comparable specificity with SSA. Furthermore, gradient boosting classifier detects 10% more unknown potential ADR signals than SSA.

CONCLUSIONS

Our study demonstrates that gradient boosting classifier is a promising supervised signal detection tool for ADRs in medication dispensing data to complement SSA.

Meta-analysis of genome-wide association studies on the intolerance of angiotensin-converting enzyme inhibitors

OBJECTIVES

To identify single nucleotide polymorphisms (SNPs) associated with switching from an angiotensin-converting enzyme (ACE)-inhibitor to an angiotensin receptor blocker.

METHODS

Two cohorts of patients starting ACE-inhibitors were identified within the Rotterdam Study in the Netherlands and the Genetics of Diabetes Audit and Research in Tayside Scotland study in Scotland. Cases were intolerant patients who switched from an ACE-inhibitor to an angiotensin receptor blocker and controls were individuals who used ACE-inhibitors continuously for at least 2 years and did not switch. Genome-wide association study (GWAS) using an additive model was run in these sets and the results were meta-analysed using Genome-Wide Association Meta Analysis software.

RESULTS

A total of 972 cases out of 5161 ACE-inhibitor starters were identified. Eight SNPs within four genes reached the genome-wide association study significance level (P<5×10) in the meta-analysis [RNA binding protein, Fox-1 homolog (Caenorhabditis elegans), γ-aminobutyric acid receptor subunit γ-2, sarcoma (Src) homology 2 (SH2) B adaptor protein 1 and membrane bound O-acyltransferase domain containing 1]. The strongest associated SNP was located in an intron of RNA binding protein, Fox-1 homolog (Caenorhabditis elegans), which contains an RNA binding protein [rs2061538: minor allele frequency=0.16, odds ratio=1.52 (95% confidence interval: 1.32-1.76), P=6.2×10].

CONCLUSION

These results indicate that genetic variation in the above-mentioned genes may increase the risk of ACE-inhibitor-induced adverse reactions.

Comparison of diagnostic evaluations for cough among initiators of angiotensin converting enzyme inhibitors and angiotensin receptor blockers

PURPOSE

Differential diagnostic evaluation associated with a drug may bias effect estimates because of an increased detection of preclinical outcomes. Persistent cough is a common side effect with angiotensin-converting enzyme inhibitors (ACEI), and we hypothesized that ACEI initiators would undergo more diagnostic evaluations, potentially leading to diagnosis of preclinical lung cancer. We compared the incidence of cough-related diagnostic evaluations and lung cancer among ACEI versus angiotensin receptor blockers (ARB) initiators.

METHODS

Using a 20% sample of Medicare claims 2007-2012, we identified initiators of ACEI or ARB, age 66-99 years. Incidence of diagnostic evaluation and lung cancer were compared using adjusted Cox models. Monthly probabilities of workup were compared using proportion differences.

RESULTS

There were 342 611 and 108 116 ACEI and ARB initiators, respectively. Monthly probability of chest X-rays ranged from minimum 4.7% to maximum 21.2% in the 6 months pre and post-initiation. Differences in incidence of diagnostic procedures in the 6 months after initiation were only minimal (chest X-rays hazard ratio (HR) = 1.12; 95% CI: 1.10-1.14), chest-MRI (0.86, 95% CI: 0.74-0.99), CT-scans (1.09, 95% CI: 0.99-1.18) or bronchoscopies (1.03, 95% CI: 0.83-1.29). Proportion differences for chest X-rays peaked in the month pre-initiation (8.4%, 95% CI: 8.1-8.6) but negligible thereafter. There was no difference in the incidence of lung cancer among ACEI versus ARB initiators (HR = 0.99, 95% CI: 0.84-1.16).

CONCLUSION

Results indicate minimal differential chest workup after ACEI versus ARB initiation and no difference in lung cancer incidence, but suggest differential workup in the month before the first recorded prescription. The latter may reflect drug use before the first observed pharmacy claim or increased workup before initiation of ACEI therapy. Copyright © 2016 John Wiley & Sons, Ltd.

Lornoxicam Side Effects May Lead to Surgical Mismanagement, in Case of Postoperative Intra-Abdominal Collection: A Case Report and Literature Review

Postoperative collection is a known complication of abdominal surgery, especially after major surgery; however, minor surgical procedures may also be associated with this phenomenon. Utilization of nonsteroidal anti-inflammatory drugs, such as lornoxicam, and the adverse effects thereof, may affect the surgeon's judgment regarding the need for, and extent of, draining of these collections. Here I report the case of a 25-year-old male who presented with perforated acute retrocaecal subhepatic appendicitis complicated by pleural effusion and a small abdominal collection. The pleural effusion resolved almost completely over time. However, the patient showed incomplete recovery, as demonstrated by nausea, vomiting, and mood disturbance along with abdominal pain, tachycardia, and a persistent small abdominal collection. We initially suspected infection caused by a highly virulent type of bacteria and planned to perform percutaneous drainage. However, owing to skin erythematic changes, administration of lornoxicam was ceased, which resulted in complete recovery of the symptoms and consequently in avoidance of unnecessary invasive intervention to drain the abdominal collection. These findings suggest that the utilization and adverse effects of some painkillers for postoperative pain, such as lornoxicam, may affect the surgeon's judgment regarding the most appropriate surgical workup in cases of postoperative fluid collection.

Cardiovascular drugs and erectile dysfunction - a symmetry analysis

AIM

Erectile dysfunction is a common problem among patients with cardiovascular diseases and the influence of cardiovascular drugs is much debated. The aim of this study was to evaluate the short term potential for different cardiovascular drugs to affect the risk of being prescribed a drug against erectile dysfunction.

METHODS

We employed a symmetry analysis design and included all Danish male individuals born before 1950 who filled their first ever prescription for a cardiovascular drug and a 5-phosphodiesterase inhibitor within a 6 month interval during 2002-2012. If the cardiovascular drug induces erectile dysfunction, this would manifest as a non-symmetrical distribution of subjects being prescribed the cardiovascular drug first vs. persons following the opposite pattern. Furthermore, we calculated the number of patients needed to treat for one additional patient to be treated for erectile dysfunction (NNTH).

RESULTS

We identified 20 072 males with a median age of 64 years (IQR 60-70) who initiated a cardiovascular drug and a 5-phosphodiesterase inhibitor within a 6 month interval. Sequence ratios showed minor asymmetry in prescription orders after adjustment for trends in prescribing. This asymmetry was most profound for thiazides (1.28, 95% CI 1.20, 1.38), calcium channel blockers (1.29, 95% CI 1.21, 1.38) and ACE inhibitors (1.29, 95% CI 1.21, 1.37), suggesting a small liability of these drugs to provoke erectile dysfunction. NNTH values were generally large, in the range of 330-6400, corresponding to small absolute effects.

CONCLUSION

Our study does not suggest that cardiovascular drugs strongly affect the risk of being prescribed a drug against erectile dysfunction on a short term basis.

Change in prescription pattern as a potential marker for adverse drug reactions of angiotensin converting enzyme inhibitors

Background Angiotensin converting enzyme inhibitors (ACEIs) are among the most frequently prescribed groups of medications. ACEI-induced adverse drug reactions (ADRs) are the main reason to discontinue or switch ACEI treatment. ADRs information is not available in prescription databases. Objective To identify a proxy for ACEI-induced ADRs in prescription databases. Setting The Rotterdam Study is an ongoing prospective cohort study that started in 1990 in the Netherlands and has included 14,926 subjects aged 45 years or older. Methods All ACEI starters from 2000 to 2011 were identified using prescription data within the Rotterdam Study. Participants were classified into 4 mutually exclusive groups: continuing, discontinuing, switching to angiotensin receptor blockers (ARBs), and switching to other antihypertensives. For categorization, the maximum time-interval between two prescription periods was set at 3 and 6 months. Subsequently, primary care physician files were searched and clinical events were classified as definite ADRs, probable ADRs, possible ADRs and definite non-ADRs. Finally the accuracy of different prescription patterns as indicators of ADRs was evaluated. Main outcome measure Positive predictive values (PPVs), negative predictive values (NPVs), sensitivity and specificity of the prescription patterns of the 4 groups were calculated. Results Totally, 1132 ACEI starters were included. The PPV for a definite ADR was 56.1 % for switchers to ARB, while the PPVs for switchers to other antihypertensives, and discontinuation were 39.5 and 19.5 %, respectively. After including probable ADRs and possible ADRs, PPVs for switchers to ARB increased to 68.3 and 90.5 %. A 6-month interval gave slightly higher PPVs compared to a 3-month interval (maximum 6.1 % higher). The differences in NPVs between 3 and 6-months interval groups were approximately 1.0 %. Conclusions Switching ACEIs to ARBs is the best marker for ACEI-induced ADRs in prescription databases.

Does a cardiovascular event change adherence to statin treatment in patients with type 2 diabetes? A matched cohort design

OBJECTIVE

To be effective, adherence to statin treatment is essential. We assessed the effect of an apparent first cardiovascular event on statin adherence rates in type 2 diabetes patients.

RESEARCH DESIGN AND METHODS

A matched cohort study was conducted among type 2 diabetes patients initiating statin treatment for primary prevention in the Groningen University IADB.nl pharmacy database. Patients who had a drug-treated cardiovascular event (index date) after statin initiation were matched to a reference patient without such an event with similar gender, age at statin initiation, initiation date, follow-up period and adherence level before the event. Adherence rates were measured as percentages of days covered (PDC), and shifts in adherence levels (non-adherent/partially adherent/fully adherent) and rates around the event were evaluated.

RESULTS

We could match 375 of the 855 eligible index patients to a reference patient. Index patients had on average a PDC of 81% after the index date; reference patients had a PDC of 71% (p < 0.001) while both had a PDC of 79% before the index date. Index patients were 4.5 times more likely than reference patients to shift from non-adherent to fully adherent (95% CI 1.1-18.8) and 1.8 times more likely to shift from partially adherent to fully adherent (95% CI 1.2-2.6). In the index group, 26% of patients became more adherent after the first cardiovascular event. In contrast, 20% of patients became less adherent.

LIMITATIONS

Medication proxies were used, which could have caused misclassification. Furthermore, a substantial group of index patients could not be matched to a reference patient due to small ranges in matching criteria.

CONCLUSIONS

The occurrence of a drug-treated cardiovascular event appeared to avert the declining statin adherence rate observed in diabetes patients without such an event. On the other hand, one in five patients became less adherent after the event, indicating that there are still important benefits to achieve.

The performance of sequence symmetry analysis as a tool for post-market surveillance of newly marketed medicines: a simulation study

Background

Sequence symmetry analysis (SSA) is a potential tool for rapid detection of adverse drug events (ADRs) associated with newly marketed medicines utilizing computerized claims data. SSA is robust to patient specific confounders but it is sensitive to the underlying utilization trends in the medicines of interest. Methods to adjust for utilisation trends have been developed, however, there has been no systematic investigation to assess the performance of SSA when variable prescribing trends occur. The objective of this study was to evaluate the validity of SSA as a signal detection tool for newly marketed medicines.

Methods

Randomly simulated prescription supplies for a population of 1 million were generated for two medicines, DrugA (medicine of interest) and DrugB (medicine indicative of an adverse event). Scenarios were created by varying medicine utilization trends for a newly marketed medicine (DrugA). In addition, the magnitude of association between DrugA and DrugB was varied. For each scenario 1000 simulations were generated. Average Adjusted Sequence Ratios (ASR), bootstrapped 95% confidence intervals (CIs), percentage of CI's which covered the expected ASR and percent relative bias were calculated.

Results

When no association was simulated between DrugA and DrugB, over 95% of SSA CI's covered the expected ASR (ASR = 1) and relative bias was 1% or less irrespective of medicine utilization trends. In scenarios where DrugA and DrugB were associated (ASR = 2), unadjusted SR's were underestimated by between 11.7 and 15.3%. After adjustment for trend, ASR estimates were close to expected with relative bias less than 1%. Power was over 80% in all scenarios except for one scenario in which medicine uptake was gradual and the effect of interest was weak (ASR = 1.2).

Conclusions

Adjustment for underlying medicine utilization patterns effectively overcomes potential under-ascertainment bias in SSA analyses. SSA may be effectively applied as a safety signal detection tool for newly marketed medicines where sufficiently large health claim data are available.

The effects of antitussive treatment of ACE inhibitor-induced cough on therapy compliance: a prescription sequence symmetry analysis

BACKGROUND

A common adverse effect of angiotensin-converting enzyme inhibitors (ACEI) is a persistent dry cough. Physicians and pharmacists who fail to recognise dry cough to be ACEI related may prescribe antitussives, instead of recommended ACEI substitution.

OBJECTIVE

The aim of this study was to determine the influence of antitussive treatment of ACEI-induced cough on ACEI therapy compliance.

METHODS

Prescription data from community pharmacies between 2000 and 2012 were retrieved from the IADB.nl database (InterAction Database) in The Netherlands. A prescription sequence symmetry analysis was used to determine whether antitussive agents were prescribed more often following ACEI initiation (cases) than the other way around (controls). ACEI therapy compliance was assessed using the proportion of days covered (PDC) method; patients with a PDC of at least 80 % were considered compliant. Compliance was compared between patients receiving antitussives for ACEI-induced cough and patients receiving antitussives for other reasons and patients who did not receive antitussives.

RESULTS

A total of 1,898 starters of ACEI and antitussives within a half-year time span were included. A significant excess of patients received antitussives after ACEI initiation compared with before ACEI initiation (1,269 cases vs. 629 controls), yielding a sequence ratio of 2.0 (95 % CI 1.8-2.2). The estimated proportion of patients with ACEI-induced cough receiving antitussives decreased over time: from 20.4 % in 2000-2004 to 8.0 % in 2008-2012. ACEI therapy compliance in patients receiving antitussives due to ACEI initiation was 52.4 %, significantly lower than compliance in control patients receiving antitussives for cough unrelated to ACEI (75.5 %, P < 0.001) and control patients who did not receive antitussives (75.2 %, P < 0.001).

CONCLUSIONS

Many patients receive antitussives after ACEI initiation. This suggests that ACEI-induced cough is often either not recognized as being ACEI related or is symptomatically treated. Such prescription behaviour may decrease ACEI therapy compliance.

Inhaled corticosteroids and the occurrence of oral candidiasis: a prescription sequence symmetry analysis

OBJECTIVES

The primary aim of the study was to gain insight into the relative risk of clinically relevant oral candidiasis following inhaled corticosteroid (ICS) initiation over time. A secondary aim was to analyse the influence of patient characteristics and co-medication on the occurrence of this adverse effect.

METHODS

Drug prescription data from 1994 to 2011 were retrieved from the IADB.nl database. To study the influence of ICS use on occurrence of oral candidiasis, a prescription symmetry analysis was used, including patients using medication for oral candidiasis up to 1 year before or after ICS initiation. The relative risk was calculated by dividing the number of patients receiving medication for oral candidiasis after ICS initiation by the number of patients receiving the same medication before ICS initiation. Sub-analyses were conducted to compare the relative risks at several time points after ICS initiation and to account for therapy persistence by only including chronic users of ICS. A multivariate logistic regression model was used to identify predictive factors.

RESULTS

A total of 52,279 incident users of ICS therapy were identified, of which 1,081 received medication for oral candidiasis up to 1 year before or after ICS initiation. A total of 701 patients received medication for oral candidiasis after ICS initiation, while 361 received these medications in the reversed sequence, resulting in a sequence ratio (SR) of 1.94 (95 % CI 1.71-2.21). In the first 3 months after ICS initiation, the SR was 2.72 (95 % CI 2.19-3.38) and then decreased to 1.47 (95 % CI 1.11-1.95) 9-12 months after ICS initiation. Predictive factors were higher daily dose of ICS and concomitant use of oral corticosteroids.

CONCLUSIONS

This study found a significant and clinically relevant increased number of patients receiving medication for oral candidiasis in the first year after therapy initiation with ICS. Relative risk is highest in the first 3 months, but remains increased up to at least 1 year after ICS initiation. This study stresses the need for patient education and inhalation instruction.

Factors that favor the occurrence of cough in patients treated with ramipril--a pharmacoepidemiological study

Background

Dry cough is a common cause for the discontinuation of ramipril treatment. The aim of this pharmacoepidemiological study was to assess the incidence of ramipril-related cough among the Polish population and to characterize patients at risk of experiencing the adverse effect of cough during ramipril treatment.

Material/Methods

This was a prospective observational study involving 10,380 patients treated with ramipril for a period of no longer than 8 weeks, consisting of 3 visits: baseline, first follow-up (after 4–8 weeks) and second follow-up visit (after 4–8 weeks of cessation of ramipril, conducted only for evaluating coughing patients).

Results

The incidence of ramipril-related cough was 7.1%. Logistic regression analysis identified female sex (OR=1.35), cigarette smoking (OR=2.50), chronic obstructive pulmonary disease (OR=1.70), asthma (OR=1.60) and previous history of tuberculosis (OR=6.20) to be significantly and independently associated with the onset of ramipril-related cough.

Coughing subsided within a period of 2–20 days after ramipril was discontinued. In all patients reporting the appearance of cough within the first 5 days after therapy initiation, the adverse effect subsided after therapy discontinuation. If cough appeared within 6–10 days, it subsided after discontinuation in 81.6% of subjects. Cough persisted in 30.4% of those reporting later onset.

Conclusions

1. Female sex, cigarette smoking, COPD, asthma, and previous history of tuberculosis increase the risk of ramipril-related cough. 2. The later the cough occurs during treatment, the less often the drug is the causative agent and the cough and also less likely to disappear after discontinuation of ramipril.

As a rare cause of drug-induced cough: topiramate

The most common causes of chronic cough in nonsmokers are postnasal drip syndrome, asthma, and gastroesophageal reflux disease. Drugs are also important in the etiology of resistant cough. Most common drugs inducing cough are the ACE inhibitors. Many drugs other than ACE inhibitors can also cause dry cough and one among them is topiramate. It is a new generation, efficacy-proved antiepileptic drug that is used widely for migraine prophylaxis in many countries. Most common adverse events of topiramate are paresthesia, cognitive symptoms, fatigue, insomnia, nausea, loss of apetite, anxiety, and dizziness. There is only one case report about topiramate associated cough in the literature. The present report refers to a patient, presenting with cough who is on topiramate treatment for migraine prophylaxis.

Attenuation of angiotensin converting enzyme inhibitor induced cough by iron supplementation: role of nitric oxide

The present study examined whether (1) the cough associated with angiotensin converting enzyme inhibitor therapy is attenuated by oral intake of iron and anti-oxidants, and (2) nitric oxide (NO) has any role in this attenuation. Of the 100 patients under investigation, cough occurred in 28 of them with preponderance in females. All the 28 patients were followed up for six weeks: the first two weeks were the observation period and the remaining four weeks the experimentation period. After the observation period, 11 patients received a single oral dose of ferrous sulphate (200 mg), eight received vitamin E (200 mg, o.d.) and vitamin C (150 mg, o.d.) and nine were given placebo during the experimentation period. Cough scoring, serum NO and malondialdehyde (MDA) levels were determined during both the periods. While there were significant decreases in cough scores, NO and MDA levels between these two periods in the iron group, cough scores and MDA level decreased significantly in the anti-oxidant group. None of these parameters changed in the control group. NO level was found to be increased significantly in patients who developed cough (n = 28) compared with those who did not cough (n = 72). These results suggest that iron supplementation suppresses cough in patients on ACE-I therapy through its effect on NO generation.

Different in vivo functions of the two catalytic domains of angiotensin-converting enzyme (ACE)

Angiotensin-converting enzyme (ACE) can cleave angiotensin I, bradykinin, neurotensin and many other peptide substrates in vitro. In part, this is due to the structure of ACE, a protein composed of two independent catalytic domains. Until very recently, little was known regarding the specific in vivo role of each ACE domain, and they were commonly regarded as equivalent. This is not true, as shown by mouse models with a genetic inactivation of either the ACE N- or C-domain. In vivo, most angiotensin II is produced by the ACE C-domain. Some peptides, such as the anti-fibrotic peptide AcSDKP, are substrates only of the ACE N-domain. Knowing the in vivo role of each ACE domain has great significance for developing ACE domain-specific inhibitors and for understanding the full effects of the anti-ACE pharmaceuticals in widespread clinical use.

Angiotensin-converting enzyme inhibitor associated cough: deceptive information from the Physicians' Desk Reference

BACKGROUND

Dry cough is a common, annoying adverse effect of all angiotensin-converting enzyme (ACE) inhibitors. The present study was designed to compare the rate of coughs reported in the literature with reported rates in the Physicians' Desk Reference (PDR)/drug label.

METHODS

We searched MEDLINE/EMBASE/CENTRAL for articles published from 1990 to the present about randomized clinical trials (RCTs) of ACE inhibitors with a sample size of at least 100 patients in the ACE inhibitors arm with follow-up for at least 3 months and reporting the incidence or withdrawal rates due to cough. Baseline characteristics, cohort enrolled, metrics used to assess cough, incidence, and withdrawal rates due to cough were abstracted.

RESULTS

One hundred twenty-five studies that satisfied our inclusion criteria enrolled 198,130 patients. The pooled weighted incidence of cough for enalapril was 11.48% (95% confidence interval [CI], 9.54% to 13.41%), which was ninefold greater compared to the reported rate in the PDR/drug label (1.3%). The pooled weighted withdrawal rate due to cough for enalapril was 2.57% (95% CI, 2.40-2.74), which was 31-fold greater compared to the reported rate in the PDR/drug label (0.1%). The incidence of cough has increased progressively over the last 2 decades with accumulating data, but it has been reported consistently several-fold less in the PDR compared to the RCTs. The results were similar for most other ACE inhibitors.

CONCLUSION

The incidence of ACE inhibitor-associated cough and the withdrawal rate (the more objective metric) due to cough is significantly greater in the literature than reported in the PDR/drug label and is likely to be even greater in the real world when compared with the data from RCTs. There exists a gap between the data available from the literature and that which is presented to the consumers (prescribing physicians and patients).