Dose adjustment guidelines for medications in patients with renal impairment: how consistent are drug information sources?

Inappropriate prescribing in patients with kidney disease: A rapid review of prevalence, associated clinical outcomes and impact of interventions

BACKGROUND

The prevalence of patients with chronic kidney disease (CKD) and polypharmacy is increasing and has amplified the importance of examining inappropriate prescribing (IP) in CKD. This review focuses on the latest research regarding the prevalence of IP in CKD and the related adverse clinical effects and explores new interventions against IP.

METHOD

A literature search was performed using PubMed, EMBASE and the Cochrane Library searching articles published between June 2016 and March 2022.

RESULTS

Twenty-seven studies were included. An IP prevalence of 12.6% to 96% and 0.3% to 66% was reported in hospital and outpatient settings, respectively. In nonhospital settings, the prevalence of IP varied between 3.9% and 60%. IP was associated with higher risk of hospitalisation (HR 1.46, 95% CI 1.17-1.81), higher bleeding rate (HR 2.34, 95% CI 1.32 to 3.37) and higher risk of all-cause mortality (OR 1.07, 95% CI 1.02 to 1.13). Three studies reported the impact of interventions on IP.

CONCLUSION

This review highlights widespread IP in CKD patients across healthcare settings, with varying prevalence rates. IP is substantially linked to adverse outcomes in patients. While limited interventions show promise, urgent research is needed to develop effective strategies addressing IP and improving CKD patient care.

Nephrotoxic drug burden and predictors of exposure among patients with renal impairment in Ethiopia: A multi-center study

Background

Nephrotoxic drugs may hasten the decline in kidney function and worsen the progression of renal impairment as a result; these drugs should be avoided or used with caution in patients with pre-existing renal insufficiency. The purpose of this study was to assess the burden of nephrotoxic medication use and its predictors among patients with underlying renal impairment.

Methods

A multicenter, institution-based, cross-sectional study was conducted from May 30, 2021 to July 30, 2021, at medical wards. Renal impaired patients admitted during the data collection period who took at least one medication were enrolled in the study. A simple random sampling technique was used to select the study participants. Data was collected through an interview and a medical card review. Both bivariable and multivariable binary logistic regression analyses were fitted to identify factors associated with nephrotoxic drug use.

Results

Among the 422 participants, more than half of them (53.6 %) were male. The mean patient's age was 47.5 (±16.7) years. A total of 1310 drugs were prescribed for 422 patients with renal impairment, of which 80.15 % were nephrotoxic. Nephrotoxic drugs were prescribed for 66.4 % of patients. The burden of nephrotoxic medication prescription was significantly associated with variables like the presence of comorbidity (AOR = 6.31, 95 % CI: 2.01-19.79), the number of medications prescribed (AOR = 1.43, 95 % CI: 1.05-1.93), and the age of participants (AOR = 1.12, 95 % CI: 1.07-1.17).

Conclusion

The present study demonstrated that two-third of the patients with renal impairment were exposed to nephrotoxic medications. Furosemide, Enalapril, and vancomycin were the most frequently prescribed nephrotoxic medications. The study suggests that prescribers need to give special attention to older patients who have underlying renal insufficiency, a comorbid condition, and polypharmacy regarding exposure to contraindicated nephrotoxic medication.

Renally Inappropriate Medications in the Old Population: Prevalence, Risk Factors, Adverse Outcomes, and Potential Interventions

Like most organs, the renal system decreases in function as we age. In the elderly, chronic kidney disease is common. When patients with chronic kidney disease take nephrotoxic medications, they are more likely to suffer adverse drug reactions, be hospitalized, and spend an extended period in the hospital. Calculating the renal clearance of a drug dose based on its glomerular filtration rate, or creatinine clearance, is necessary. Multiple tools are available for identifying renally inappropriate medications (RIMs). RIM prescriptions can be influenced by various factors, which vary according to the study. A higher number of medications means a higher likelihood of using RIMs. Numerous studies have investigated RIMs. The most contraindicated drug in renal insufficiency patients was a non-steroidal anti-inflammatory medication. A variety of interventions have been used to reduce RIM prescriptions to varying degrees of success.

Choosing the right chronic medication for hemodialysis patients. A short ABC for the dialysis nephrologist

BACKGROUND

Adapting drug treatments for patients on hemodialysis with multiple chronic pathologies is a complex affair. When prescribing a medication, the risk-benefit analysis usually focuses primarily on the indication of the drug class prescribed. However, the pharmacokinetics of the chosen drug should also be taken into account. The purpose of our review was to identify the drugs to be favored in each therapeutic class, according to their safety and pharmacokinetic profiles, for the most common chronic diseases in patients on chronic hemodialysis.

METHODS

We conducted a narrative review of the literature using Medline and Web of Science databases, targeting studies on the most commonly-prescribed drugs for non-communicable diseases in patients on chronic hemodialysis.

RESULTS

The search identified 1224 articles, 95 of which were further analyzed. The main classes of drugs included concern the cardiovascular system (anti-hypertensives, anti-arrhythmics, anti-thrombotics, hypocholesterolemics), the endocrine and metabolic pathways (anti-diabetics, gastric anti-secretory, anticoagulant, thyroid hormones, anti-gout) and psychiatric and neurological disorders (antidepressants, anxiolytics, antipsychotics and anti-epileptics).

CONCLUSION

We report on the most often prescribed drugs for chronic pathologies in patients on chronic hemodialysis. Most of them require adaptation, and in some cases one better alternative stands out among the drug class. More pharmacokinetic data are needed to define the pharmacokinetics in the various dialysis techniques.

Renally inappropriate medications in elderly outpatients and inpatients with an impaired renal function

BACKGROUND AND AIMS

The purpose of this study was to investigate differences in the frequency of renally inappropriate medications (RIMs) in outpatient and inpatient among three institutions.

METHODS

We collected prescription and renal function data for patients over 65 years of age from the drug department system. We selected 50 kinds of the most frequently used medicines which require dose adjustment according to a patient's renal function.

RESULTS

Outpatient RIM was seen in 611 cases (6.17%), and inpatient prescription RIM was seen in 317 cases (5.29%), showing a significant difference between the groups (odds ratio [OR] 1.18, 95% confidence interval [CI] 1.02-1.35). However, in a multivariate analysis, when the renal function was included, that difference between outpatients and inpatients became insignificant (OR 1.16, 95% CI 0.98-1.37). The distribution of prescription with or without RIM in outpatient and inpatient settings depended on the CKD stage. Outpatients with a better CKD stage (stage 1-3) had a higher rate of RIM than inpatients, while patients with a worse CKD stage (stage 4 or 5) had a higher rate of RIM than outpatients.

CONCLUSION

The rate of RIM in outpatients tends to be high, and attention should be paid to RIM in inpatients with a severe CKD stage.

Appropriateness of drug prescriptions in patients with chronic kidney disease in primary care: a double-center retrospective study

BACKGROUND

Chronic kidney disease (CKD) is a highly prevalent disease worldwide. A basic pillar for the management of a patient with CKD is the safe use of drugs. Inadequate dosing of medication or contraindicated drugs in renal impairment can lead to negative outcomes. The primary objective was to analyse the drug prescriptions of patients with CKD from two primary care centres to see if they were optimally adapted to the patient's estimated glomerular filtration rate (eGFR).

METHODS

A retrospective observational study was conducted in two urban primary care centres. The study period was between September-October 2019. Patients over 18 years of age, with established CKD and with an eGFR less than 60 mL/min/1.73m² for at least three months were included. Their demographic data (age and sex) and clinical variables such as associated comorbidities, eGFR value were retrospectively registered. Finally, their medication plans were reviewed in order to detect: inappropriate prescribing (IP), defined as an incorrect dose/frequency or contraindicated drug according to the renal function of the patient; nephrotoxic drugs and drugs with a high sodium content.

RESULTS

A total of 273 patients were included. The most common patient profile was an elderly woman, polymedicated, with other concomitant diseases and with mild CKD. Two hundred and one IPs were detected, 13.9% of which were contraindicated drugs. Of all patients, 49.1% had been prescribed at least one IP on their medication plan, 93.8% had some potentially nephrotoxic drug and 8.4% had drugs with a high sodium content prescribed.

CONCLUSIONS

Patients with CKD are at increased risk of medication-related problems. It is necessary to implement measures to improve the safety in the prescription of drugs in patients with CKD.

Evaluation of medication dose adjustments in patients with impaired renal function using different online drug information databases

OBJECTIVES

Clinical pharmacist-led medication dose adjustment is required to provide safe and effective pharmacotherapy in patients with impaired renal function. This study aimed to assess clinical pharmacist-led medication dose adjustments in hospitalised patients with impaired renal function by comparing three online drug information databases.

METHODS

This retrospective observational study was conducted in an internal medicine ward between November 2016 and February 2017 among hospitalised patients with at least one estimated glomerular filtration rate (eGFR) value <60 mL/min/1.73 m2. Clinical pharmacist-led medication dose adjustments according to eGFR were performed by comparing three online drug information databases: Micromedex, Medscape and Lexicomp. The number of items related to dose adjustments detected during the study period and the concordance between databases were evaluated.

RESULTS

This study was conducted among 100 hospitalised patients (mean age 74.6±13.2 years) with impaired renal function. Clinical pharmacists detected at least one medication dose adjustment in 71.0% of patients. Among these patients, it was found that physician-led medication dose adjustments were made in only 15.5% of them. Of 1053 medications, the number of medications that required dose adjustments were 149 (14.2%), 151 (14.3%) and 163 (15.5%) according to Micromedex, Medscape and Lexicomp, respectively. The Fleiss kappa coefficient was 0.875 and the agreement of the three clinical decision support systems were almost perfect.

CONCLUSIONS

In renal dose adjustments, Micromedex, Lexicomp and Medscape are concordant as online drug information databases. Clinical pharmacists could detect medication dose adjustment requirements in hospital patients with impaired renal function. The potential positive impact of clinical pharmacist-led medication dose adjustment should be investigated in further studies.

Comparison of antimicrobial dosing recommendations in patients receiving intermittent hemodialysis among drug information resources

WHAT IS KNOWN AND OBJECTIVE

Tertiary drug information resources are frequently consulted for the optimal antimicrobial dosing in intermittent hemodialysis (IHD) patients. Yet, significant discrepancy may exist in dosing recommendations between resources. This study was to evaluate the consistency of antimicrobial dosing recommendations in IHD among four different drug information resources and the relevance of referenced pharmacokinetic studies.

METHODS

Dosing recommendations of 29 commonly prescribed antimicrobials in IHD patients were collected from Micromedex, LexiComp, Clinical Pharmacology and Drug Prescribing in Renal Impairment to compare dosing categorization and the total daily dose (TDD). Significant dosing discrepancies were defined as ≥30% difference. Referenced pharmacokinetic studies were evaluated for their relevance in current practice, using sample size, hemodialyzer types, the use of optimal pharmacodynamic targets and the consideration of different interdialytic dosing periods.

RESULTS AND DISCUSSION

A significant variation was found both in dosing categorization and recommended doses between resources. Seventeen drugs were compared for TDD with significant dosing discrepancy in 8 drugs. Among 42 referenced pharmacokinetic studies, 40 were evaluated. Mean patient numbers of pharmacokinetic studies were 13 ranging from 3 to 70. Sixty per cent of studies utilized contemporary hemodialyzers (e.g., high-flux and/or high efficiency). The optimal pharmacodynamic targets and the impact of different interdialytic intervals were assessed only in 27.5% and 7.5% respectively.

WHAT IS NEW AND CONCLUSION

Inconsistent antimicrobial dosing recommendations for IHD patients exist among four well-established resources. Many referenced pharmacokinetic studies utilized outdated or less pharmacodynamically relevant study methods. Newer studies are warranted to reflect contemporary dialysis practice and assess its impact on optimal antimicrobial dosing.

Drug-Related Problems in Hospitalised Patients with Chronic Kidney Disease: A Systematic Review

INTRODUCTION

Globally, chronic kidney disease (CKD) is one of the leading causes of mortality. Impaired renal function makes CKD patients vulnerable to drug-related problems (DRPs).

AIM

The aim of this systematic review was to investigate the prevalence and nature of DRPs among hospital in-patients with CKD.

METHODS

A systematic review of the literature was conducted using Medline, EMBASE, PsycINFO, Web of Science (Core Collection), CINAHL plus (EBSCO), Cochrane Library (Wiley), Scopus (ELSEVIER) and PubMed (U.S.NLM) from index inception to January 2020. Studies investigating DRPs in hospitalised CKD patients published in the English language were included. Two independent reviewers extracted the data and undertook quality assessment using the Joanna Briggs Institute (JBI) tool.

RESULTS

A total of 2895 unique titles were identified; with 20 meeting the inclusion criteria. DRPs prevalence in CKD was reported between 12 and 87%. The most common DRPs included ineffective treatment, inappropriate drug choice and dosing problems. Antibiotics, H2-antihistamines and oral antidiabetics (metformin) were common drug classes involved in DRPs. Factors associated with DRPs included severity of CKD, the number of medications taken, age, length of hospital stay, and gender.

CONCLUSION

This systematic review provides evidence that DRPs are a frequent occurrence and burden for hospitalised patients with stage 1-4 CKD. Heterogeneity in study design, case detection and definitions are common, and future studies should use clearer definitions and study designs. Protocol Registration: PROSPERO: CRD42018096364.

Drug dosing in cancer patients with decreased kidney function: A practical approach

Correct drug dosing of anticancer agents is essential to obtain optimal outcomes. Overdosing will result in increased toxicity, treatment interruption and possible cessation of anticancer treatment. Underdosing may result in suboptimal anti-cancer effects and may increase the risk of cancer-related mortality. As it is practical nor feasible to perform therapeutic drug monitoring for all anti-cancer drugs, kidney function is used to guide drug dosing for those drugs whose primary mode of excretion is through the kidney. However, it is not well-established what method should be utilized to measure or estimate kidney function and the choice of method does influence treatment decisions regarding eligibility for anti-cancer drugs and their dose. In this review, we will provide an overview regarding the importance of drug dosing, the preferred method to determine kidney function and a practical approach to drug dosing of anticancer drugs.

Effect of ageing on antiretroviral drug pharmacokinetics using clinical data combined with modelling and simulation

AIMS

The impact of ageing on antiretroviral pharmacokinetics remains uncertain, leading to missing dosing recommendations for elderly people living with human immunodeficiency virus (HIV: PLWH). The objective of this study was to investigate whether ageing leads to clinically relevant pharmacokinetic changes of antiretrovirals that would support a dose adjustment based on the age of the treated PLWH.

METHODS

Plasma concentrations for 10 first-line antiretrovirals were obtained in PLWH ≥55 years, participating in the Swiss HIV Cohort Study, and used to proof the predictive performance of our physiologically based pharmacokinetic (PBPK) model. The verified PBPK model predicted the continuous effect of ageing on HIV drug pharmacokinetics across adulthood (20-99 years). The impact of ethnicity on age-related pharmacokinetic changes between whites and other races was statistically analysed.

RESULTS

Clinically observed concentration-time profiles of all investigated antiretrovirals were generally within the 95% confidence interval of the PBPK simulations, demonstrating the predictive power of the modelling approach used. The predicted decline in drug clearance drove age-related pharmacokinetic changes of antiretrovirals, resulting in a maximal 70% [95% confidence interval: 40%, 120%] increase in antiretrovirals exposure across adulthood. Peak concentration, time to peak concentration and apparent volume of distribution were predicted to be unaltered by ageing. There was no statistically significant difference of age-related pharmacokinetic changes between studied ethnicities.

CONCLUSION

Dose adjustment for antiretrovirals based on the age of male and female PLWH is a priori not necessary in the absence of severe comorbidities considering the large safety margin of the current first-line HIV treatments.

Quality use of medicines in patients with chronic kidney disease

BACKGROUND

Chronic kidney disease (CKD) affects drug elimination and patients with CKD require appropriate adjustment of renally cleared medications to ensure safe and effective pharmacotherapy. The main objective of this study was to determine the extent of potentially inappropriate prescribing (PIP; defined as the use of a contraindicated medication or inappropriately high dose according to the kidney function) of renally-cleared medications commonly prescribed in Australian primary care, based on two measures of kidney function. A secondary aim was to assess agreement between the two measures.

METHODS

Retrospective analysis of routinely collected de-identified Australian general practice patient data (NPS MedicineWise MedicineInsight from January 1, 2013, to June 1, 2016; collected from 329 general practices). All adults (aged ≥18 years) with CKD presenting to general practices across Australia were included in the analysis. Patients were considered to have CKD if they had two or more estimated glomerular filtration rate (eGFR) recorded values < 60 mL/min/1.73m², and/or two urinary albumin/creatinine ratios ≥3.5 mg/mmol in females (≥2.5 mg/mmol in males) at least 90 days apart. PIP was assessed for 49 commonly prescribed medications using the Cockcroft-Gault (CG) equation/eGFR as per the instructions in the Australian Medicines Handbook.

RESULTS

A total of 48,731 patients met the Kidney Health Australia (KHA) definition for CKD and had prescriptions recorded within 90 days of measuring serum creatinine (SCr)/estimated glomerular filtration rate (eGFR). Overall, 28,729 patients were prescribed one or more of the 49 medications of interest. Approximately 35% (n = 9926) of these patients had at least one PIP based on either the Cockcroft-Gault (CG) equation or eGFR (CKD-EPI; CKD-Epidemiology Collaboration Equation). There was good agreement between CG and eGFR while determining the appropriateness of medications, with approximately 97% of the medications classified as appropriate by eGFR also being considered appropriate by the CG equation.

CONCLUSION

This study highlights that PIP commonly occurs in primary care patients with CKD and the need for further research to understand why and how this can be minimised. The findings also show that the eGFR provides clinicians a potential alternative to the CG formula when estimating kidney function to guide drug appropriateness and dosing.

Medication burden and inappropriate prescription risk among elderly with advanced chronic kidney disease

BACKGROUND

Elderly patients with chronic kidney disease (CKD) frequently present comorbidities that put them at risk of polypharmacy and medication-related problems. This study aims to describe the overall medication profile of patients aged ≥75 years with advanced CKD from a multicenter French study and specifically the renally (RIMs) and potentially inappropriate-for-the-elderly medications (PIMs) that they take.

METHODS

This is a cross-sectional analysis of medication profiles of individuals aged ≥75 years with eGFR < 20 ml/min/1.73 m2 followed by a nephrologist, who collected their active prescriptions at the study inclusion visit. Medication profiles were first analyzed according to route of administration, therapeutic classification. Second, patients were classified according to their risk of potential medication-related problems, based on whether the prescription was a RIM or a PIM. RIMs and PIMs have been defined according to renal appropriateness guidelines and to Beer's criteria in the elderly. RIMs were subclassified by 4 types of category: (a) contraindication; (b) dose modification is recommended based on creatinine clearance (CrCl); (c) dose modification based on CrCl is not recommended but a maximum daily dose is mentioned, (d) no specific recommendations based on CrCl: "use with caution", "avoid in severe impairment", "careful monitoring of dose is required" "reduce the dose".

RESULTS

We collected 5196 individual medication prescriptions for 556 patients, for a median of 9 daily medications [7-11]. Antihypertensive agents, antithrombotics, and antianemics were the classes most frequently prescribed. Moreover, 77.0% of patients had at least 1 medication classified as a RIM. They accounted 31.3% of the drugs prescribed and 9.25% was contraindicated drugs. At least 1 PIM was taken by 57.6 and 45.5% of patients had at least one medication classified as RIM and PIM. The prescriptions most frequently requiring reassessment due to potential adverse effects were for proton pump inhibitors and allopurinol. The PIMs for which deprescription is especially important in this population are rilmenidine, long-term benzodiazepines, and anticholinergic drugs such as hydroxyzine.

CONCLUSION

We showed potential drug-related problems in elderly patients with advanced CKD. Healthcare providers must reassess each medication prescribed for this population, particularly the specific medications identified here.

TRIAL REGISTRATION

NCT02910908.

Adjustments of medication dosages in patients with renal impairment in Botswana; findings and implications to improve patient care

Background and aims: Medication dosage adjustments for renally impaired patients have not been studied in Botswana. This study was conducted to determine prescribing practices among patients with renal impairment in medical wards to improve future patient care.Methods: We conducted a retrospective study involving medical charts of patients admitted at a tertiary level hospital in Gaborone Botswana. Study participants included all patients admitted between August and October 2016 who were hospitalized for ≥24 h. 'Drug prescribing in renal failure: dosing guidelines for adults and children'. was used to determine the extent of dosage adjustments. A logistic regression model was used to assess which patient factors were associated with inappropriate dosage adjustment.Results: Twenty-nine percent (233/804) of patients had renal impairment. Of these, 184 patients with renal impairment were included in the final analysis. There were 1143 prescription entries, of which 20.5% (n = 234) required dosage adjustment for renal function but only 45.7% (n = 107) were adjusted correctly. Of note, 112 patients were prescribed at least one drug that required dosage adjustment and only 30.4% (n = 34) patients had all of their medications appropriately adjusted. Patient factors associated with inappropriate dosage adjustment included a higher number of medicines being prescribed. Mortality among patients with renal impairment was independently associated with higher scores of the Charlson comorbidity index and hospital stay duration of 1-7 days.Conclusion: The renal function status of patients was not sufficiently taken into account when prescribing medicines especially in patients with severely impaired kidney function in Botswana. Continuous medical education needs to be encouraged to address this, which is being implemented. We will be following this up in future studies.

Clinical Pharmacology of Antibiotics

Antimicrobial pharmacology and its effect on prescribing is quite complex. Selecting an antibiotic that will optimally treat an infection while minimizing adverse effects and the development of resistance is only the first step, as one must also consider the patient's individual pharmacokinetic alterations and the pharmacodynamic properties of the drug when prescribing it as well. Patients with CKD may have alterations in their protein binding, volumes of distribution, kidney clearance, and nonrenal clearance that necessitates antibiotic dose adjustments to prevent the development of toxicity. Knowledge of a drug's pharmacodynamics, defined as the relationship between drug exposure and antibacterial efficacy, provides some guidance regarding the optimal way to make dose adjustments. Different pharmacodynamic goals, such as maximizing the time that free (unbound) drug concentrations spend above the minimum inhibitory concentration (MIC) for time dependent drugs (e.g., β-lactams) or maximizing the free peak-to-MIC ratio for concentration-dependent antibiotics (e.g., aminoglycosides), require different adjustment strategies; for instance, decreasing the dose while maintaining normal dosing frequency or giving normal (or even larger) doses less frequently, respectively. Patients receiving hemodialysis have other important prescribing considerations as well. The nephrologist or patient may prefer to receive antibiotics that can be administered intravenously toward the end of a dialysis session. Additionally, newer dialysis technologies and filters can increase drug removal more than originally reported. This review will discuss the place in therapy, mechanism of action, pharmacokinetic, pharmacodynamic, and other pharmacologic considerations encountered when prescribing commonly used antibiotics in patients with chronic kidney disease or ESKD.

Use of renal risk drugs in a nation-wide Polish older adult population: an analysis of PolSenior database

BACKGROUND

Numerous medications should be avoided, or require dose adjustment in subjects with impaired kidney function. We aimed to assess the prevalence of potentially inappropriate use of renal risk drugs in a nation-wide, community-dwelling Polish older adult population.

METHODS

We analysed regular intake of 38 medications that should be avoided, requiring dose modification, increase the risk of pre-renal kidney injury, or may cause potassium retention in subjects with moderately to severely impaired renal function in the PolSenior data base (N = 4514, mean age 76 ± 11 yrs). Kidney function was assessed with short Modification of Diet in Renal Disease formula estimated glomerular filtration rate (sMDRD) and Cockcroft-Gault creatinine clearance (CC).

RESULTS

There were 855 (19%) individuals with sMDRD < 60 ml/min/1.73m2, and 1734 (38%) with CC <  60 ml/min. Among drugs that should be avoided, spironolactone (20.4% of patients as classified by sMDRD and 17.5% by CC), non-steroidal anti-inflammatory drugs (13.4 and 11.3%), hydrochlorothiazide (11.1 and 11.0%), and metformin (6.9 and 8.2%) were most frequently used. The most frequently used drugs requiring dose modification were piracetam (13.9% by sMDRD, and 11.9% by CC), digoxin (8.3 and 8.8%), and gliclazide (6.8 and 5.9%). Classification of a drug use as 'appropriate' or 'inappropriate' was discordant depending on the method of kidney function assessment (sMDRD or CC) in up to 30%. Subgroups with sMDRD < 60 ml/min/1.73m2 and with CC <  60 ml/min were taking ≥2 drugs increasing the risk of pre-renal kidney injury more frequently than individuals with better kidney function (46.6 vs. 23.1 and 33.0% vs. 24.4%, respectively). There were 24.7% of individuals with sMDRD < 60 ml/min/1.73m2 and 18.0% with CC <  60 ml/min taking 2 or more drugs increasing serum potassium level. The proportion of subjects with hyperkalaemia increased with the number of such drugs.

CONCLUSIONS

Use of drugs that should be avoided or require dose adjustment due to renal impairment, and potentially inappropriate drug combinations is a common problem in older adults in Poland. Assessment of kidney function with sMDRD may result in overlooking of requirements for dose adjustment formulated based on creatinine clearance.

TRIAL REGISTRATION

Not applicable.

Kidney Function, Polypharmacy, and Potentially Inappropriate Medication Use in a Community-Based Cohort of Older Adults

BACKGROUND

Chronic kidney disease (CKD) afflicts many older adults and increases the risk for medication-related adverse events.

OBJECTIVE

The aim of this study was to assess the prevalence and associated morbidity and mortality of polypharmacy (use of several medications concurrently), and potentially inappropriate medication (PIM) use in older adults, looking for differences by CKD status.

METHODS

We quantified medication and PIM use (from Beers criteria, the Screening Tool of Older People's Prescriptions, and Micromedex^®) by level of estimated glomerular filtration rate (eGFR) for participants aged 65 years or older attending a baseline study visit in the Atherosclerosis Risk in Communities study (n =6392). We used zero-inflated negative binomial and Cox proportional hazards regressions to assess the relationship between baseline polypharmacy, PIM use, and subsequent hospitalization and death.

RESULTS

Mean age at baseline was 76 (± 5) years, 59% were female, and 29% had CKD (eGFR < 60 ml/min/1.73 m²). Overall, participants reported 6.1 (± 3.5) medications and 2.3 (± 2.2) vitamins/supplements; 16% reported ≥ 10 medications; 31% reported a PIM based on their age. On average, participants with CKD reported more medications. A PIM based on kidney function was used by 36% of those with eGFR < 30 ml/min/1.73 m². Over a median of 2.6 years, more concurrent medications were associated with higher risk of hospitalization and death, but PIM use was not. While those with CKD had higher absolute risks, there was no difference in the relative risks associated with greater numbers of medications by CKD status.

CONCLUSION

Polypharmacy and PIM use were common, with greater numbers of medications associated with higher risk of hospitalization and death; relative risks were similar for those with and without CKD.

Prevalence of renally inappropriate medicines in older people with renal impairment - A cross-sectional register-based study in a large primary care population

The aim of this population-based, cross-sectional study was to analyse the prevalence of renally inappropriate medicines (RIMs) in older people with renal impairment. We included 30 372 people aged ≥65 years with chronic kidney disease (CKD) stage 3, and 2161 with stage 4 attending primary care in Stockholm, Sweden. We used data derived from SCREAM, a database linking patient-specific data on demography, morbidity, healthcare consumption and dispensed drugs to creatinine measurements. Estimated glomerular filtration rate was calculated with CKD-EPI based on the first non-hospital serum creatinine in 2010. RIMs were defined as medicines needing dose adjustment or being contra-indicated in CKD stage 3 or 4 with reference to Swedish "Janusmed Drugs and Renal function." Dispensed prescription drugs were analysed during 1 year after creatinine assessment. Drug doses were considered as excessive if their mean volume dispensed per day exceeded the recommended dose. Contra-indicated medicines were regarded as inappropriate if dispensed at least once during 1 year. Excessive dosing was present in 42.5% of older people with CKD stage 3 and in 58.1% with stage 4. The prevalence of contra-indicated medicines was 9.4% and 38.0%, respectively. A limited number of RIMs accounted for the majority of excessive dosing, such as drugs acting on the renin-angiotensin-aldosterone system, betablockers and opioids. Commonly dispensed contra-indicated substances were NSAIDs and antidiabetics. We conclude that the prevalence of RIMs in older people with renal impairment is considerably high. Still, RIM use may be manageable as only a limited number of RIMs are frequently used.

Prescription of high-risk medications among patients with chronic kidney disease: a cross-sectional study from the Washington, Wyoming, Alaska, Montana and Idaho region Practice and Research Network

Background

Patients with chronic kidney disease (CKD) are at high risk for adverse drug events related to medication dosing errors and prescriptions for relatively contraindicated medications, such as non-steroidal anti-inflammatory drugs (NSAIDs).

Objectives

To examine the scope of and variation in prescribing relatively contraindicated medications and medications above the recommended dose levels among patients with stage III/IV CKD in primary care practice.

Methods

This is a cross-sectional descriptive study that used structured electronic health record data. The study participants were patients aged 18 years and older from three primary care clinics in a practice-based research network. Number/proportion of adult patients with stage III/IV CKD; proportion of these patients with at least one NSAID or other relatively contraindicated medication prescribed over 2 years.

Results

Of the 7586 eligible adult patients, 4.9% had stage III/IV CKD; 46.6% of these 373 patients with stage III/IV CKD were prescribed at least one relatively contraindicated drug (acarbose, chlorpropamide, glyburide, nitrofurantoin or any NSAID) during the 2-year study period; and 34.0% of patients with stage III/IV CKD were prescribed NSAIDs.

Conclusions

Primary care patients with stage III/IV CKD were frequently prescribed or had documented use of relatively contraindicated drugs and thus were at risk of adverse drug events. Given the significant number of individuals with CKD in the USA, research that examines rates of adverse events related to these prescriptions and that tests primary care-based interventions to decrease inappropriate prescribing of relatively contraindicated medications to these patients is needed.

Clinical Pharmacokinetics in Kidney Disease: Application to Rational Design of Dosing Regimens

A change in pharmacokinetics can alter drug exposure and predispose the patient to either over- or underdosing, potentially resulting in adverse drug reactions or therapeutic failure. Kidney disease is characterized by multiple physiologic effects, which induce clinically significant changes in pharmacokinetics. These vary between individuals and may be quantitated in certain instances. An understanding of pharmacokinetic concepts is, therefore, important for a rational approach to the design of drug dosing regimens for the delivery of personalized medical care. Whether kidney disease is acute or chronic, drug clearance decreases and the volume of distribution may remain unchanged or increase. AKI is defined by dynamic changes in kidney function, which complicates attempts to accurately quantify drug clearance. In contrast, changes in drug clearance progress more slowly with CKD. In general, kidney replacement therapies increase drug clearance, but the extent to which this occurs depends on the modality used and its duration, the drug's properties, and the timing of drug administration. However, the changes in drug handling associated with kidney disease are not isolated to reduced kidney clearance and an appreciation of the scale of potential derangements is important. In most instances, the first dose administered in patients with kidney disease is the same as in patients with normal kidney function. However, in some cases, a higher (loading) initial dose is given to rapidly achieve therapeutic concentrations, followed by a lower maintenance dose, as is well described when prescribing anti-infectives to patients with sepsis and AKI. This review provides an overview of how pharmacokinetic principles can be applied to patients with kidney disease to personalize dosage regimens. Patients with kidney disease are a vulnerable population and the increasing prevalence of kidney disease means that these considerations are important for all prescribers.

Clinical Pharmacokinetics in Kidney Disease: Fundamental Principles

Kidney disease is an increasingly common comorbidity that alters the pharmacokinetics of many drugs. Prescribing to patients with kidney disease requires knowledge about the drug, the extent of the patient's altered physiology, and pharmacokinetic principles that influence the design of dosing regimens. There are multiple physiologic effects of impaired kidney function, and the extent to which they occur in an individual at any given time can be difficult to define. Although some guidelines are available for dosing in kidney disease, they may be on the basis of limited data or not widely applicable, and therefore, an understanding of pharmacokinetic principles and how to apply them is important to the practicing clinician. Whether kidney disease is acute or chronic, drug clearance decreases, and the volume of distribution may remain the same or increase. Although in CKD, these changes progress relatively slowly, they are dynamic in AKI, and recovery is possible depending on the etiology and treatments. This, and the use of kidney replacement therapies further complicate attempts to quantify drug clearance at the time of prescribing and dosing in AKI. The required change in the dosing regimen can be estimated or even quantitated in certain instances through the application of pharmacokinetic principles to guide rational drug dosing. This offers an opportunity to provide personalized medical care and minimizes adverse drug events from either under- or overdosing. We discuss the principles of pharmacokinetics that are fundamental for the design of an appropriate dosing regimen in this review.

Agreement between renal prescribing references and determination of prescribing appropriateness in hospitalized patients with chronic kidney disease

BACKGROUND

Chronic kidney disease (CKD) is a risk factor for adverse drug events. The clinical significance of discordance between renal prescribing references is unknown.

AIM

We determined the prevalence of potentially inappropriate prescribing (PIP) in CKD, measured agreement between two prescribing references, and assessed potential for harm consequent to PIP.

DESIGN

Single-centre observational study.

METHODS

A random sample of hospitalized patients with CKD were grouped according to baseline CKD stage (3, 4, or 5). Prescriptions requiring caution in CKD were referenced against the Renal Drug Handbook (RDH) and British National Formulary (BNF) to identify PIP (non-compliance with recommendations). Inter-reference agreement was measured using percentage agreement and Kappa coefficient. Potential for harm consequent to PIP was assessed by physicians and pharmacists using a validated scale. One-year mortality was compared between patients with or without PIP during admission.

RESULTS

Among 119 patients (median age 73 years, 50% male), 136 cases of PIP were identified in 78 (65.5%) patients. PIP prevalence, per patient, was 64.7% using the BNF and 28.6% using the RDH (fair agreement, Kappa 0.33, P <  0.001). The majority (63.2%) of PIP cases detected exclusively by the BNF carried minimal or no potential for harm. PIP was not significantly associated with one-year mortality (34.7% vs. 21.1%, P = 0.14).

CONCLUSIONS

PIP was common in hospitalized patients with CKD. Substantial discordance between renal prescribing references was apparent. The development of universally-adopted, evidence-based, prescribing guidelines for CKD might optimize medications safety in this vulnerable group.

Development of a tool to assess the completeness of drug information sources for health care professionals: A Delphi study

The aim of this study was to create a standard set of essential drug information items as a tool to assess the completeness of any type of drug information source, regardless of its length, using a Delphi consensus panel of European health care professionals. A compilation of drug-related information items was performed by searching several resources for health care professionals and a final list of 162 items was obtained. Fifty-seven experts in drug information from 23 different European countries were invited to participate in a three-round Delphi technique to obtain consensus on items considered essential and non-essential content of information. Consensus for the first, second, and third rounds was defined as ≥90%, ≥80%, and ≥75% agreement, respectively. Of the 57 experts invited, 32 completed the first round, 27 the second, and 29 the third. Consensus was achieved for 28.3% of the items in the first round, 49.3% in the second, and 58.3% in the third. The final cumulative consensus was 67.7% (n = 126) for items considered essential and 16.1% (n = 30) for items considered non-essential. The final tool obtained to assess the completeness of drug information sources was composed by 126 essential items grouped into 11 sections. This tool allows for the comparison of different information sources for the same medicine and the information content for different medicines in the same source.

Inappropriate prescribing in chronic kidney disease: A systematic review of prevalence, associated clinical outcomes and impact of interventions

INTRODUCTION

Adjusting doses of renally cleared medications and/or avoidance of nephrotoxic medications are standard clinical practices in chronic kidney disease (CKD), albeit the prevalence of inappropriate prescribing (IP) in these patients remains high. Therefore, this work sought to systematically review the prevalence of IP and compare the relative effectiveness of available interventions in reducing IP in CKD.

METHODS

Studies were identified searching PubMed/Medline, EMBASE, Cochrane Library, IPA, Web of Science, Ovid/Medline, CINAHL, and PsychINFO databases. Studies defining CKD based on laboratory markers and quantifying prevalence of IP were included.

RESULTS

Forty-nine studies from 23 countries met the inclusion criteria. An IP prevalence of 9.4%-81.1% and 13%-80.50% was reported in hospital and ambulatory settings, respectively; whereas, in long-term care facilities the prevalence ranged between 16% and 37.9%. Unsurprisingly, IP was associated with adverse drug events like increased hospital stay (Mean [SD] of 4.5 [4.8] vs 4.3 [4.5]) and high risk of mortality [40%]. Twenty-one studies reported the impact of interventions on IP; manual and computerised alerts were the main forms of interventions (n=19). The most significant reduction in IP was observed when physicians received immediate concurrent feedback from a clinical pharmacist (P<.001). Polypharmacy, comorbidities, and age were identified as predictors of IP.

CONCLUSION

IP has led to poor patient outcomes. Although pharmacist-based and computer-aided approaches have shown promising results, there is still room for improvement. Future studies should focus on developing a multifaceted intervention to address the widespread prevalence of IP and associated clinical outcomes in CKD patients.

Guidance to develop individual dose recommendations for patients on chronic hemodialysis

INTRODUCTION

In addition to tailored clinical trials in patients on chronic hemodialysis (HD) during drug development, clinician-initiated post-marketing studies and case reports on individual pharmacokinetic (PK) assessments provide an important source of information about drug dialysability and individualized dose recommendations in this vulnerable population. Areas covered: First, factors that may alter drug exposure in HD patients are explained. Second, available regulatory and methodological guidelines for PK assessments in this population are summarized. Third, a 4-step approach is proposed to develop individual dose recommendations for HD patients receiving drugs without data from a PK study: (1) literature search, (2) model-based dosage decisions, (3) validation and refinement through concentration monitoring, and (4) publication of relevant observations. Fourth, clinician-initiated PK assessments and case reports to evaluate and individualize use of drugs in HD patients are reviewed, and recommendations to enhance their quality are discussed. Expert commentary: Guidance on collecting and reporting PK information in individual HD patients is warranted to ensure completeness and consistency of such PK studies. A checklist and template for easy-to-implement PK calculations and pharmacometric modeling is provided to facilitate evaluation and individualization of dosing strategies in these patients.

Renal Insufficiency and Medication in Nursing Home Residents. A Cross-Sectional Study (IMREN)

BACKGROUND

Nursing home residents often suffer from a multiplicity of medical conditions and take many different drugs. Many drugs are eliminated via the kidneys and thus require dose adjustment in patients with renal insufficiency. This is the first study to address the prevalence of renal insufficiency among nursing home residents in Germany, and the extent to which such persons take drugs that are contraindicated or incorrectly dosed because of renal insufficiency.

METHODS

We carried out a cross-sectional study in nursing homes in the German regions of Bremen and Lower Saxony. Data were collected by nursing staff and given to us anonymously. Whenever the nursing home data did not include a current creatinine value, the patient's general practitioner was asked to supply this value. The estimated creatinine clearance (eCCr) was calculated with the Cockcroft-Gault formula.

RESULTS

852 residents of 21 nursing homes were included in the study; eCCr values were obtainable for 685 (80.4%) of them (average age, 83.3 years; 75.2% female). 48.2% of these patients (95% confidence interval [CI] 41.8-54.5) had moderate renal insufficiency (eCCr 59-30 mL/min), and 15.5% (95% CI 12.4-18.6) had severe renal insufficiency (eCCr <30 mL/min). 19.7% were regularly taking at least one medication that was contraindicated or incorrectly dosed in the light of renal insufficiency. Predictors for such inappropriate drug use were advanced age, female sex, arterial hypertension, and polypharmacy. The drugs that were most often inappropriately used were metformin, ramipril, and potassium chloride.

CONCLUSION

Nursing home residents often suffer from renal insufficiency and should therefore have their creatinine levels measured regularly. A knowledge of the creatinine level is a prerequisite for the proper adjustment of drug doses (if necessary). A practical and compact summary of dose-adjustment recommendations for patients with renal insufficiency would be desirable but is not yet available.

Evidence and resources to implement pharmacogenetic knowledge for precision medicine

PURPOSE

The current state of pharmacogenetic data curation and dissemination is described, and evidence-based resources for applying pharmacogenetic data in clinical practice are reviewed.

SUMMARY

Implementation of pharmacogenetics in clinical practice has been relatively slow despite substantial scientific progress in understanding linkages between genetic variation and variability of drug response and effect. One factor that has inhibited the adoption of genetic data to guide medication use is a lack of knowledge of how to translate genetic test results into clinical action based on currently available evidence. Other implementation challenges include controversy over selection of appropriate evidentiary thresholds for routine clinical implementation of pharmacogenetic data and the difficulty of compiling scientific data to support clinical recommendations given that large randomized controlled trials to demonstrate the utility of pharmacogenetic testing are not feasible or are not considered necessary to establish clinical utility. Organizations such as the Clinical Pharmacogenetics Implementation Consortium (CPIC) and the Pharmacogenomics Knowledgebase (PharmGKB) systematically evaluate emerging evidence of pharmacogenomic linkages and publish evidence-based prescribing recommendations to inform clinical practice. Both CPIC and PharmGKB provide online resources that facilitate the interpretation of genetic test results and provide prescribing recommendations for specific gene-drug pairs.

CONCLUSION

Resources provided by organizations such as CPIC and PharmGKB, which use standardized approaches to evaluate the literature and provide clinical guidance for a growing number of gene-drug pairs, are essential for the implementation of pharmacogenetics into routine clinical practice.

Inappropriate Prescription and Renal Function Among Older Patients with Cognitive Impairment

BACKGROUND

Older people are more sensitive to drugs and adverse drug reactions than younger people because of age-related physiological changes such as impaired renal function. As people with dementia are particularly vulnerable to the effects of drugs, it is especially important to evaluate the dosages of renally cleared medications in this group.

OBJECTIVE

The aim of this study was to estimate the prevalence of impaired renal function and inappropriate prescriptions on the basis of renal function among older patients with dementia or cognitive impairment.

METHODS

The medical records of 428 patients aged ≥65 years who were admitted to two hospitals in northern Sweden were reviewed and renally cleared medications were identified. The Cockcroft-Gault equation was used to evaluate renal function. Doses were evaluated according to the Geriatric Dosage Handbook.

RESULTS

Renal function was impaired (estimated glomerular filtration rate <60 ml/min) in 65.4 % of the study population. Impaired renal function was associated with increasing age. Among 547 prescriptions identified as renally cleared medications, 9.1 % were inappropriate based on the patient's renal function; 13.5 % of the 326 patients prescribed renally cleared medications had inappropriate prescriptions. Inappropriate prescriptions were more common among patients living in nursing homes.

CONCLUSIONS

Impaired renal function is common and inappropriate prescription is prevalent among old people with cognitive impairment in northern Sweden. Continuous consideration of renal function is important when prescribing medications to this group.

Potentially inappropriate prescribing of renally cleared drugs in elderly patients in community and aged care settings

BACKGROUND

Limited data are available on the prevalence of inappropriate prescribing of renally cleared drugs in elderly patients in Australia.

OBJECTIVES

To quantify and compare the extent of inappropriate prescribing (defined as at least one drug prescribed in an excessive dose or when contraindicated with respect to renal function) of renally cleared drugs in elderly patients across the community and aged care settings, and to determine factors associated with patients being prescribed one or more potentially inappropriate renally cleared drugs.

METHODS

This retrospective study examined de-identified Home Medicines Review (HMR) and Residential Medication Management Review (RMMR) cases pertaining to 30,898 patients aged 65 years and over. Only 25 % (n = 7625) of these patients had documented information on their renal function. Among them, 4035 patients were prescribed at least one of the 31 renally cleared drugs examined in this study. For these patients, details including demographics, medications, medical conditions and pathology test results were extracted. Creatinine clearance was estimated using the Cockcroft-Gault formula, and the prevalence of inappropriate prescribing of the 31 drugs was examined on the basis of conformity with the recommendations in the Australian Medicines Handbook. Multivariate logistic regression was performed to determine the factors associated with patients being prescribed one or more potentially inappropriate renally cleared drugs.

RESULTS

The mean (± standard deviation) ages of the HMR patients (n = 3315; 59 % female) and RMMR patients (n = 720; 68 % female) were 78.3 ± 7.2 and 86 ± 7.3 years, respectively. Over one quarter of the patients (n = 1135 out of 4035; 28.1 %) prescribed the renally cleared drugs examined in this study had evidence of inappropriate prescribing of at least one of the drugs, with respect to their renal function. The drugs/drug classes most commonly prescribed inappropriately were perindopril, fenofibrate, glibenclamide, gliptins, metformin, olmesartan, bisphosphonates and strontium. The factors independently associated with patients being prescribed one or more potentially inappropriate renally cleared drugs were advancing age [odds ratio (OR) 1.06 per year increase, 95 % confidence interval (CI) 1.05-1.07; P < 0.001], the total number of renally cleared drugs prescribed (OR 1.44 per unit increase, 95 % CI 1.29-1.61; P < 0.001), presence of diabetes (OR 1.51, 95 % CI 1.30-1.76; P < 0.001), presence of heart failure (OR 1.38, 95 % CI 1.13-1.69; P < 0.005) and living in aged care facilities (OR 1.28, 95 % CI 1.06-1.5; P < 0.05).

CONCLUSION

Inappropriate prescribing of renally cleared drugs is common in older Australians. Intervention studies to improve prescribing of renally cleared drugs in the elderly appear to be warranted.

Adherence with renal dosing recommendations in outpatients undergoing haemodialysis

WHAT IS KNOWN AND OBJECTIVE

Adjustment of drug dosage in patients with end-stage renal disease prevents serious adverse effects, which occur due to the accumulation of drugs or other toxic metabolites. Nevertheless, dosing errors occur most commonly among patients with end-stage renal disease. The aim of this study was to assess the quality of care for end-stage renal disease outpatients using their renal dosing adjustment status.

METHODS

A cross-sectional study was performed using the data collected from 43 South Korean medical institutions via questionnaires. A total of 2428 patients on haemodialysis, who were at least 18 years of age, were included. Among these patients, the study population was confined to patients who were taking medications and required renal dosing adjustments from three therapeutic classes: antihypertensives, antihyperglycaemics and lipid-modifying agents. The study population (n = 828) was prescribed a total of 1097 drug orders for the target drugs. Determination of appropriate dosage adjustment was based on GFR (glomerular filtration rate) using the Modification of Diet in Renal Disease revised 4-variable equation. The primary outcome was non-adherence to drug dosing requirements for end-stage renal disease patients with consideration to their renal function.

RESULTS AND DISCUSSION

Among the study population (n = 828), 469 haemodialysis patients were identified as having drug orders that were adherent to renal dosing recommendations. There were significant differences between the patient groups who received recommendation-adherent and non-adherent drug orders in the characteristics of the medical institutions they visited, causes of chronic renal failure and prevalence of concurrent diabetes mellitus. The primary factor of non-adherence to renal dosing adjustment recommendations was characteristics of medical institutions. Compared to tertiary hospitals, secondary hospitals and primary care clinics were 1·16 and 1·22 times, respectively, more non-adherent in accordance with the multivariate analysis (OR: 1.16, 95% CI: 1.02-1.20, OR: 1.22, 95% CI: 1·00-1·36, respectively).

WHAT IS NEW AND CONCLUSIONS

Dosing error is one of the most common problems among patients with renal failure. To decrease the dosing errors, an improvement needs to be made in medical institutions. This can be accomplished by implementing the clinical decision support systems that educate physicians on appropriate renal dosing and help them prescribe appropriate drug dosages.

Use of Renally Inappropriate Medications in Older Veterans: A National Study

OBJECTIVES

To determine how many ambulatory older adults with chronic kidney disease receive medications that are contraindicated or dosed excessively given their level of renal function.

DESIGN

Cross-sectional retrospective study.

SETTING

U.S. Department of Veterans Affairs (VA) clinics.

PARTICIPANTS

Individuals aged 65 and older with a creatinine clearance (CrCl) of 15 to 49 mL/min (N = 83,850; mean age 80; 96% male).

MEASUREMENTS

Forty medications that require dose adjustment or are contraindicated in people with impaired renal function were examined. Medication use and CrCl (calculated using the Cockroft-Gault equation) were assessed using VA pharmacy, laboratory, and other data sources as of October 2007.

RESULTS

Thirteen percent of older veterans with a CrCl of 30 to 49 mL/min and 32% of those with a CrCl of 15 to 29 mL/min received one or more drugs that were contraindicated or prescribed at an excessive dose given the individual's level of renal function. The strongest risk factor for renally inappropriate prescribing was number of medications used; the risk of receiving renally inappropriate medications was 5.5 times as high (95% confidence interval = 5.1-5.9) in older adults taking 10 or more medications as in those taking one to three medications. Ranitidine, allopurinol, and metformin together accounted for 76% of renally misprescribed medications in individuals with a CrCl of 30 to 49 mL/min. Glyburide, ranitidine, gemfibrozil, carvedilol, and allopurinol accounted for 47% of renally misprescribed drugs for individuals with a CrCl of 15 to 29 mL/min.

CONCLUSION

Inappropriate prescribing of renally cleared medications is common in ambulatory older veterans, with only a few medications accounting for most of these prescribing problems.

Drug-Induced Nephrotoxicity and Dose Adjustment Recommendations: Agreement Among Four Drug Information Sources

Hospitalized patients require the use of a variety of drugs, many of which individually or in combination have the potential to cause kidney damage. The use of potentially nephrotoxic drugs is often unavoidable, and the need for dose adjustment should be evaluated. This study is aimed at assessing concordance in information on drug-induced nephrotoxicity and dose adjustment recommendations by comparing four drug information sources (DRUGDEX^®, UpToDate^®, Medscape^® and the Brazilian Therapeutic Formulary) using the formulary of a Brazilian public hospital. A total of 218 drugs were investigated. The global Fleiss’ kappa coefficient was 0.265 for nephrotoxicity (p < 0.001; CI 95%, 0.211–0.319) and 0.346 for recommendations (p < 0.001; CI 95%, 0.292–0.401), indicating fair concordance among the sources. Anti-infectives and anti-hypertensives were the main drugs cited as nephrotoxic by the different sources. There were no clear definitions for qualitative data or quantitative values for dose adjustments among the four information sources. There was no advice for dosing for a large number of the drugs in the international databases. The National Therapeutic Formulary offered imprecise dose adjustment recommendations for many nephrotoxic drugs. Discrepancies among information sources may have a clinical impact on patient care and contribute to drug-related morbidity and mortality.

Use of renal risk drugs in patients with renal impairment

BACKGROUND

Renal impairment often goes unrecognised until the most advanced stages. Patients with renal impairment use a variety of drugs and the pharmacokinetics and drug effects are prone to change.

OBJECTIVE

Describe drug related problems in a population of patients with renal impairment, investigate possible risk factors, and investigate whether the clinical pharmacist can propose relevant measures to solve the problems.

SETTING

The internal medicine department at Innlandet Hospital Trust Gjøvik, Norway.

METHOD

A prospective study enrolling patients (≥18 years) with moderate and severe renal impairment, i.e. with glomerular filtration rate of 30-59 and 15-29 ml/min/1.73 m(2), respectively, and using at least one drug. The clinical pharmacist reviewed the patients' drug regimen with focus on drug related problems, related to renal function. Problems identified were discussed with the multidisciplinary team, or directly with the physician.

MAIN OUTCOME MEASURE

The number of drug related problems.

RESULTS

The results are based on data from 79 patients, 21 with severe and 58 with moderate renal impairment. Most patients, 92.4 %, used 5 or more drugs; in average 10.2 (range 2-27). In total, 88 drug related problems were identified in 49 patients, i.e. in 62 %. The most frequently occurring problems were incorrect dose (45.5 %) and inappropriate drug (41.0 %). There was a significant correlation between both the degree of renal impairment and the number of drugs, and the number of drug related problems. The acceptance rate of the clinical pharmacist's interventions was 95.7 %. The drugs most frequently associated with drug related problems were metformin, benzylpenicillin and furosemide.

CONCLUSION

Drug related problems often occur in patients with renal impairment. Incorrect drug dose and inappropriate drug choice according to the patients' renal function were the most common problems. Patients with the most complex drug treatment, i.e. with increasing degree of renal impairment and increasing number of drugs, are at greater risk of drug related problems. The high acceptance rate for the pharmacist's interventions supports the inclusion of a clinical pharmacist in the multidisciplinary treatment team to increase awareness and optimisation of the drug treatment in this patient group.

Retrospective evaluation of potentially inappropriate prescribing in hospitalized patients with renal impairment

BACKGROUND/AIMS

Patients with chronic kidney disease require appropriate adjustment of nephrotoxic and renally cleared medications to ensure safe and effective pharmacotherapy. It is currently unclear how often appropriate medication selection and dosage adjustment occurs in practice. Therefore, this study aimed to evaluate the extent of potentially inappropriate prescribing (PIP) (the use of a contraindicated medication or inappropriately high dose according to the renal function) in patients with renal impairment from admission through to discharge from the Royal Hobart Hospital (RHH), Tasmania, Australia; to evaluate the medications most commonly implicated in PIP; and the factors associated with PIP in renal impairment.

METHODS

Medical records of 251 patients consecutively admitted to the RHH aged 40 years and above, with a creatinine clearance of ≤60 mL/min, and hypertension and/or diabetes mellitus in their medical history, were reviewed. PIP was assessed using the Australian Medicines Handbook and/or product information.

RESULTS

Of the 251 patients, 81 (32.3%) were receiving a total of 116 potentially inappropriate medications (PIMs) at the time of admission. The number of patients receiving PIMs (81 vs. 44, p<0.001 chi-square test) as well as the total number of PIMs (116 vs. 63, p<0.001 Wilcoxon signed rank test) were significantly decreased at discharge. Metformin was the most common PIM at admission. However, PIP of metformin was reduced by approximately 50% by discharge. Logistic regression analysis revealed two significant independent risk factors for PIP: a higher number of medications at admission increased risk of PIP (OR 1.1, 95% CI 1.02-1.18, p=0.010), and higher initial estimated glomerular filtration rate (eGFR) decreased the risk of PIP (OR 0.9, 95% CI 0.96-0.99, p=0.011).

CONCLUSIONS

Despite the limitations of lack of body weight documentation and lack of clear guidelines for dosage adjustment based on the eGFR, PIP in patients with renal impairment is common and admission to the hospital was associated with a significant reduction in PIP. More recognition of chronic kidney disease in the community and strategies to alert clinicians of the need for dosage adjustment in renal impairment are warranted.

Renal drug dosing recommendations: evaluation of product information for brands of the same drug

OBJECTIVES

To review the product information (PI) for various brands of the same generic drugs and investigate the extent to which information is currently available on dosing in renal impairment and the concordance between the dosing recommendations for the same generic drug.

METHOD

The Monthly Index of Medical Specialities (MIMS) was examined for 28 generic drugs recommended to be used with caution in renal impairment. For each generic drug all available brands listed as having solid oral dosage form were recorded. For each identified brand, the current PI was consulted and data referring to renal impairment was collated. The dissimilarity between these PI regarding the renal dosage recommendation was determined.

RESULTS

There was generally a lack of detailed information in the PI on the use of drugs in patients with renal impairment. The majority of PI documents (88 of 155 PI; 57%) provided quantitative dosage recommendations, but this was often not detailed enough to help users to make an informed decision. For 37 PI documents (24%), an altered dosage regimen was proposed without a quantifiable measure of renal function reported in the dose recommendation. The renal function severity category terms used and the associated quantitative values were also not consistent. It was observed that the recommendations varied among different brands of hydromorphone, morphine, oxycodone, tramadol, metformin and topiramate.

CONCLUSION

The reporting of renal function quantification methods, and associated dosage recommendations, in PI requires standardisation to ensure optimal drug dosing. Regularly updating of PI is also necessary.