Drug-drug interactions in a geriatric outpatient cohort: prevalence and relevance

Personalized medicine and opioid analgesic prescribing for chronic pain: opportunities and challenges

Use of opioid analgesics for pain management has increased dramatically over the past decade, with corresponding increases in negative sequelae including overdose and death. There is currently no well-validated objective means of accurately identifying patients likely to experience good analgesia with low side effects and abuse risk prior to initiating opioid therapy. This paper discusses the concept of data-based personalized prescribing of opioid analgesics as a means to achieve this goal. Strengths, weaknesses, and potential synergism of traditional randomized placebo-controlled trial (RCT) and practice-based evidence (PBE) methodologies as means to acquire the clinical data necessary to develop validated personalized analgesic-prescribing algorithms are overviewed. Several predictive factors that might be incorporated into such algorithms are briefly discussed, including genetic factors, differences in brain structure and function, differences in neurotransmitter pathways, and patient phenotypic variables such as negative affect, sex, and pain sensitivity. Currently available research is insufficient to inform development of quantitative analgesic-prescribing algorithms. However, responder subtype analyses made practical by the large numbers of chronic pain patients in proposed collaborative PBE pain registries, in conjunction with follow-up validation RCTs, may eventually permit development of clinically useful analgesic-prescribing algorithms.

PERSPECTIVE

Current research is insufficient to base opioid analgesic prescribing on patient characteristics. Collaborative PBE studies in large, diverse pain patient samples in conjunction with follow-up RCTs may permit development of quantitative analgesic-prescribing algorithms that could optimize opioid analgesic effectiveness and mitigate risks of opioid-related abuse and mortality.

Old and new antirheumatic drugs and the risk of hepatotoxicity

Given the high prevalence of the use of medications in daily practice and the large number of people taking antirheumatic agents, the risk of drug-drug interactions and of hepatotoxicity is of concern. Both old and new compounds show such a risk. Nonsteroidal antinflammatory drugs are widely used drugs with potential adverse hepatic reactions. Nonsteroidal antinflammatory drugs are responsible for an important aliquot of transaminase elevation in the general population. Genetic susceptibility to diclofenac hepatotoxicity has promoted the knowledge about drug-specific, class-specific reactions. Some drugs (sulfasalazine, azathioprine, and leflunomide) may cause acute liver injury, whereas other compounds (methotrexate) may cause chronic liver damage as the result of the interaction among drug, host and environmental factors. The tumor necrosis factor-alpha inhibitor, infliximab, is associated with typical drug-induced autoimmune hepatitis. Also, the other biological disease-modifying antirheumatic drugs are not free of potential hepatotoxicity. The diagnosis of drug-induced liver injury follows the exclusion of other causes, involves a temporal relationship between drug exposure and adverse event, and should consider the potential participation of the underlying rheumatic disease to event occurrence. This article also includes data regarding hepatotoxicity from our outclinic patients receiving biological disease-modifying antirheumatic drugs.

How many potential drug-drug interactions cause adverse drug reactions in hospitalized patients?

BACKGROUND

Potential drug-drug interactions (DDIs) are frequent in drug prescription but clinically significant are the ones which can result in changes of therapeutic effect of one of the two drugs or in adverse drug reactions (ADRs). The aim of this study was to assess the potential DDIs as well as the DDIs which cause adverse drug reactions (ADRs) in an internal medicine department hospitalized patients.

METHODS

The prospective study included all patients admitted between November 2010 and January 2011 in an internal medicine ward. Information on patients' demographics and their medication use history was obtained from each patient by interview. In addition, medical history, medication use during hospitalization, and relevant laboratory and clinical data were obtained from medical records. Potential DDIs were identified using the Thomson Micromedex program. Each patient was monitored during the hospitalization period in order to detect the ADRs resulting from DDI's if present.

RESULTS

Three hundred and five patients were enrolled in this study during 3 months. Of 1279 potential DDIs, Fourteen led to 13 ADRs out of which 8 were serious and caused hospital admission or prolongation of hospitalization. There was a statistically significant association between ADRs related to DDIs and the presence of ATC (Anatomical Therapeutic Chemical) C medication during hospitalization and the length of hospital stay, in the multivariate analysis.

CONCLUSION

Awareness of the most commonly occurring DDIs should be raised by the utilization of drug-drug interaction guides in the Romanian clinical practice which can help prescribers and pharmacists prevent DDI related ADRs.

Long-term tolerability of topical diclofenac sodium 1% gel for osteoarthritis in seniors and patients with comorbidities

Background

Adverse events associated with nonsteroidal anti-inflammatory drugs (NSAIDs) used to treat knee and hand osteoarthritis may be more frequent in certain patient populations. Topical NSAIDs, such as diclofenac sodium 1% gel (DSG), have equivalent efficacy and fewer adverse events compared with oral NSAIDs. This post hoc analysis assessed the long-term tolerability of DSG in elderly patients and patients with an elevated risk of gastrointestinal, cardiovascular, and renal adverse events.

Methods

Patients ≥ 35 years of age with knee osteoarthritis applied DSG (4 g) to one or both knees for 12 weeks during either of two primary studies and for 9 months during a long-term extension study. Other patients entered the long-term extension study directly and applied DSG for 12 months. Safety was assessed by reported adverse events. Subpopulations were defined based on age, or the comorbidities of hypertension, type 2 diabetes mellitus, and cerebrovascular or cardiovascular disease.

Results

The safety population consisted of 947 patients who received at least one dose of DSG during the primary or extension study. Patients aged < 65 years (68.2%) and ≥65 years (67.2%) experienced any adverse event at similar rates. The percentage of patients who experienced any adverse event was similar between patients with and without hypertension (65.5% versus 69.7%, respectively), type 2 diabetes mellitus (64.0% versus 68.2%), or cerebrovascular or cardiovascular disease (61.9% versus 68.5%). Among the 15 patients with all three comorbidities, the percentage of patients with any adverse event (53.3%) was less than that of patients who did not have all three comorbidities (68.0%).

Conclusion

These results suggest that long-term DSG treatment is safe in patient subpopulations with an elevated risk of NSAID-related adverse events, such as the elderly and those with the comorbidities of hypertension, type 2 diabetes mellitus, and cerebrovascular or cardiovascular disease.

A review of pharmacotherapy for chronic low back pain with considerations for sports medicine

Up to 30% of athletes experience low back pain (LBP) depending on sport type, sex, training intensity and frequency, and technique. United States clinical guidelines define back pain as chronic if it persists for ≥ 12 weeks, and subacute if it persists 4 to < 12 weeks. Certain sports injuries are likely to lead to chronic pain. Persistent or chronic symptoms are frequently associated with degenerative lumbar disc disease or spondylolytic stress lesions. Exercise therapy is widely used and is the most conservative form of treatment for chronic LBP (cLBP). Pharmacotherapies for cLBP include acetaminophen, nonsteroidal anti-inflammatory drugs, and opioids. Acetaminophen is a well-tolerated first-line pharmacotherapy, but high-dose, long-term use is associated with hepatic toxicity. Nonsteroidal anti-inflammatory drugs can be an effective second-line option if acetaminophen proves inadequate but they have well-known risks of gastrointestinal, cardiovascular, and other systemic adverse effects that increase with patient age, dose amount, and duration of use. The serotonin-norepinephrine reuptake inhibitor, duloxetine, has demonstrated modest efficacy and is associated with systematic adverse events, including serotonin syndrome, which can be dose related or result from interaction with other analgesics. Opioids may be an effective choice for moderate to severe pain but also have significant risks of adverse events and carry a substantial risk of addiction and abuse. Because the course of cLBP may be protracted, patients may require treatment over years or decades, and it is critical that the risk/benefit profiles of pharmacotherapies are closely evaluated to ensure that short- and long-term treatments are optimized for each patient. This article reviews the clinical evidence and the guideline recommendations for pharmacotherapy of cLBP.

Inhibitory metabolic drug interactions with newer psychotropic drugs: inclusion in package inserts and influences of concurrence in drug interaction screening software

BACKGROUND

Food and Drug Administration (FDA) regulations mandate that package inserts (PIs) include observed or predicted clinically significant drug-drug interactions (DDIs), as well as the results of pharmacokinetic studies that establish the absence of effect.

OBJECTIVE

To quantify how frequently observed metabolic inhibition DDIs affecting US-marketed psychotropics are present in FDA-approved PIs and what influence the source of DDI information has on agreement between 3 DDI screening programs.

METHODS

The scientific literature and PIs were reviewed to determine all drug pairs for which there was rigorous evidence of a metabolic inhibition interaction or noninteraction. The DDIs were tabulated noting the source of evidence and the strength of agreement over chance. Descriptive statistics were used to examine the influence of source of DDI information on agreement among 3 DDI screening tools. Logistic regression was used to assess the influence of drug class, indication, generic status, regulatory approval date, and magnitude of effect on agreement between the literature and PI as well as agreement among the DDI screening tools.

RESULTS

Thirty percent (13/44) of the metabolic inhibition DDIs affecting newer psychotropics were not mentioned in PIs. Drug class, indication, regulatory approval date, generic status, or magnitude of effect did not appear to be associated with more complete DDI information in PIs. DDIs found exclusively in PIs were 3.25 times more likely to be agreed upon by all 3 DDI screening tools than were those found exclusively in the literature. Generic status was inversely associated with agreement among the DDI screening tools (odds ratio 0.11; 95% CI 0.01 to 0.89).

CONCLUSIONS

The presence in PIs of DDI information for newer psychotropics appears to have a strong influence on agreement among DDI screening tools. Users of DDI screening software should consult more than 1 source when considering interactions involving generic psychotropics.

Medication management among home-dwelling older patients with chronic diseases: possible roles for community pharmacists

OBJECTIVE

To describe medication management among home-dwelling older adults. These data should allow us to identify potential problems and to indicate target areas for community pharmacist intervention.

DESIGN

Cross-sectional observational study.

SETTING

Community pharmacies (n=86) in Belgium.

PARTICIPANTS

Home-dwelling older adults using at least one chronic medicine (n=338).

MEASUREMENTS

Data on drug use were taken from the electronic pharmacy databases, while drug adherence was measured by pill count, self-report and estimation by GP and pharmacist. Drug knowledge and practical drug management capacity were assessed by patient interview and questionnaire, respectively.

RESULTS

The study population (n=338) used a median of 5 chronic drugs per patient. Half of our sample (n=169) used psychotropic medication chronically, mainly benzodiazepines. In 100 patients (29.6%) at least one drug-drug interaction of potential clinical significance was observed. The overall mean adherence per patient was very high (98.1%), but 39.6% of individuals was underadherent with at least one medication. Seventy-six % of patients had an acceptable knowledge of the indication for at least 75% of their medication. In nearly 15 % of the study population cognitive impairment was suspected by the mini-cog test. The participants reported several practical problems with drug taking: difficulties with vision (32.0%), blister opening (12.1%), tablet swallowing (14.8%), tablet splitting (29.7% [represents % of patients who have to split tablets]) and distinction between different drug packages (23.4%).

CONCLUSION

This study identified the following aspects of medication management by home-dwelling older adults that could be improved by pharmaceutical care services: (i) assistance of cognitively impaired patients, (ii) management of practical drug taking problems, (iii) DDI screening, (iv) drug adherence, and (v) chronic benzodiazepine use.

Impact of the drug-drug interaction database SFINX on prevalence of potentially serious drug-drug interactions in primary health care

PURPOSE

To investigate the impact of the integration of the drug-drug interaction database SFINX into primary health care records on the prevalence of potentially serious drug-drug interactions.

METHODS

The study was a controlled before-and-after study on the prevalence of potential drug-drug interactions before and after the implementation of SFINX at 15 primary healthcare centres compared with 5 centres not receiving the intervention. Data on dispensed prescriptions from health care centres were retrieved from the Swedish prescribed drug register and analysed for September-December 2006 (pre-intervention) and September-December 2007 (post-intervention). All drugs dispensed during each 4 month period were regarded as potentially interacting.

RESULTS

Use of SFINX was associated with a 17% decrease, to 1.81 × 10(-3) from 2.15 × 10(-3) interactions per prescribed drug-drug pair, in the prevalence of potentially serious drug-drug interactions (p = 0.042), whereas no significant effect was observed in the control group. The change in prevalence of potentially serious drug-drug interactions did not differ significantly between the two study groups. The majority of drug-drug interactions identified were related to chelate formation.

CONCLUSION

Prescriptions resulting in potentially serious drug-drug interactions were significantly reduced after integration of the drug-drug interaction database SFINX into electronic health records in primary care. Further studies are needed to demonstrate the effectiveness of drug-drug interaction warning systems.

Adverse drug reactions caused by drug-drug interactions in elderly outpatients: a prospective cohort study

PURPOSE

Although the prevalence of drug-drug interactions (DDIs) in elderly outpatients is high, many potential DDIs do not have any actual clinical effect, and data on the occurrence of DDI-related adverse drug reactions (ADRs) in elderly outpatients are scarce. This study aimed to determine the incidence and characteristics of DDI-related ADRs among elderly outpatients as well as the factors associated with these reactions.

METHODS

A prospective cohort study was conducted between 1 November 2010 and 31 November 2011 in the primary public health system of the Ourinhos micro-region, Brazil. Patients aged ≥60 years with at least one potential DDI were eligible for inclusion. Causality, severity, and preventability of the DDI-related ADRs were assessed independently by four clinicians using validated methods; data were analysed using descriptive analysis and multiple logistic regression.

RESULTS

A total of 433 patients completed the study. The incidence of DDI-related ADRs was 6 % (n = 30). Warfarin was the most commonly involved drug (37 % cases), followed by acetylsalicylic acid (17 %), digoxin (17 %), and spironolactone (17 %). Gastrointestinal bleeding occurred in 37 % of the DDI-related ADR cases, followed by hyperkalemia (17 %) and myopathy (13 %). The multiple logistic regression showed that age ≥80 years [odds ratio (OR) 4.4; 95 % confidence interval (CI) 3.0-6.1, p < 0.01], a Charlson comorbidity index ≥4 (OR 1.3; 95 % CI 1.1-1.8, p < 0.01), consumption of five or more drugs (OR 2.7; 95 % CI 1.9-3.1, p < 0.01), and the use of warfarin (OR 1.7; 95 % CI1.1-1.9, p < 0.01) were associated with the occurrence of DDI-related ADRs. With regard to severity, approximately 37 % of the DDI-related ADRs detected in our cohort necessitated hospital admission. All DDI-related ADRs could have been avoided (87 % were ameliorable and 13 % were preventable). The incidence of ADRs not related to DDIs was 10 % (n = 44).

CONCLUSIONS

The incidence of DDI-related ADRs in elderly outpatients is high; most events presented important clinical consequences and were preventable or ameliorable.

Adverse drug reactions caused by drug-drug interactions reported to Croatian Agency for Medicinal Products and Medical Devices: a retrospective observational study

Aim

To analyze potential and actual drug-drug interactions reported to the Spontaneous Reporting Database of the Croatian Agency for Medicinal Products and Medical Devices (HALMED) and determine their incidence.

Methods

In this retrospective observational study performed from March 2005 to December 2008, we detected potential and actual drug-drug interactions using interaction programs and analyzed them.

Results

HALMED received 1209 reports involving at least two drugs. There were 468 (38.7%) reports on potential drug-drug interactions, 94 of which (7.8% of total reports) were actual drug-drug interactions. Among actual drug-drug interaction reports, the proportion of serious adverse drug reactions (53 out of 94) and the number of drugs (n = 4) was significantly higher (P < 0.001) than among the remaining reports (580 out of 1982; n = 2, respectively). Actual drug-drug interactions most frequently involved nervous system agents (34.0%), and interactions caused by antiplatelet, anticoagulant, and non-steroidal anti-inflammatory drugs were in most cases serious. In only 12 out of 94 reports, actual drug-drug interactions were recognized by the reporter.

Conclusion

The study confirmed that the Spontaneous Reporting Database was a valuable resource for detecting actual drug-drug interactions. Also, it identified drugs leading to serious adverse drug reactions and deaths, thus indicating the areas which should be in the focus of health care education.

Pain Management in the Elderly: An FDA Safe Use Initiative Expert Panel's View on Preventable Harm Associated with NSAID Therapy

Optimization of current pain management strategies is necessary in order to reduce medication risks. Promoting patient and healthcare provider education on pain and pain medications is an essential step in reducing inadequate prescribing behaviors and adverse events. In an effort to raise awareness on medication safety, the FDA has launched the Safe Use Initiative program. The program seeks to identify areas with the greatest amount of preventable harm and help promote new methods and practices to reduce medication risks. Since the establishment of the program, FDA's Safe Use initiative staff convened a panel of key opinion leaders throughout the medical community to address pain management in older adults (≥65 years of age). The aim of the expert panel was to focus on areas where significant risk occurs and where potential interventions will be feasible, implementable, and lead to substantial impact. The panel suggested one focus could be the use of NSAIDs for pain management in the elderly.

Polypharmacy and food-drug interactions among older persons: a review

Polypharmacy is generally defined as the use of 5 or more prescription medications on a regular basis. The average number of prescribed and over-the-counter medications used by community-dwelling older adults per day in the United States is 6 medications, and the number used by institutionalized older persons is 9 medications. Almost all medications affect nutriture, either directly or indirectly, and nutriture affects drug disposition and effect. This review will highlight the issues surrounding polypharmacy, food-drug interactions, and the consequences of these interactions for the older adult.

Epidemiology and characteristics of adverse drug reactions caused by drug-drug interactions

INTRODUCTION

Drug-drug interactions (DDIs) arise in numerous different ways, involving pharmacokinetic or pharmacodynamic mechanisms. Adverse drug reactions are a possible consequence of DDIs and health operators are often unaware of the clinical risks of certain drug combinations. Many papers on drug interactions have been published in recent years, but most of them focused on potential DDIs while few studies have been conducted on actual interactions.

AREAS COVERED

This paper reviews the epidemiology of actual DDIs in outpatients as well as in hospital settings and in spontaneous reporting databases. The incidence of actual DDIs is consistently lower than that of potential DDIs. However, the absolute number of patients involved is high, representing a significant proportion of adverse drug reactions. The importance of risk factors such as age, polypharmacy and genetic polymorphisms is also evaluated. The relevance and efficacy of tools for recognizing and preventing DDIs are discussed.

EXPERT OPINION

Potential DDIs far outnumber actual drug interactions. The potential for an adverse interaction to occur is often theoretical, and clinically important adverse effects occur only in the presence of specific risk factors. Several studies have shown the efficacy of computers in early detection of DDIs. However, a correct risk-benefit evaluation by the prescribing physician, together with a careful clinical, physiological and biochemical monitoring of patients, is essential. Future directions of drug interaction research include the increasing importance of pharmacogenetics in preventing DDIs and the evaluation of interactions with biological drugs.

Topical nonsteroidal anti-inflammatory drugs for management of osteoarthritis in long-term care patients

Osteoarthritis is common in patients ≥65 years of age. Although nonsteroidal anti-inflammatory drugs (NSAIDs) are often prescribed for osteoarthritis pain, they pose age-related cardiovascular, renal, and gastrointestinal risks. Two topical NSAIDs, diclofenac sodium 1% gel (DSG) and diclofenac sodium 1.5% in 45.5% dimethylsulfoxide solution (D-DMSO), are approved in the US for the treatment of osteoarthritis pain. Topical NSAIDs have shown efficacy and safety in knee (DSG, D-DMSO) and hand (DSG) osteoarthritis. Analyses of data from randomized controlled trials of DSG in hand and knee osteoarthritis demonstrate significant improvement of pain and function in both younger patients (<65 years) and older patients (≥65 years) and suggest good safety and tolerability. However, long-term safety data in older patients are limited. Topical NSAIDs can ease medication administration and help address barriers to pain management in older patients, such as taking multiple medications and inability to swallow, and are a valuable option for long-term care providers.

Prescribing quality for older people in Norwegian nursing homes and home nursing services using multidose dispensed drugs

PURPOSE

To examine and compare the quality of drug prescribing for older patients in nursing homes and home nursing services.

METHODS

Cross-sectional study comprising 11,254 patients aged ≥ 65 years in nursing homes (n = 2986) and home nursing services (n = 8268). Potentially inappropriate medications were identified by using the Norwegian General Practice criteria and drug-drug interactions through a Norwegian Web-based tool. The impact of care setting on exposure to selected drug groups, potentially inappropriate medications, and drug interactions was calculated, adjusting for patients' age, gender, and number of drugs used.

RESULTS

Patients in nursing homes and home nursing services used on average 5.7 (SD = 2.6) multidose dispensed regular drugs. Twenty-six percent used at least one potentially inappropriate medication, 31% in nursing homes and 25% in home nursing services, p < .001. Concomitant use of three or more psychotropic and/or opioid drugs was the criterion most commonly identified in nursing homes (18%) and home nursing services (9%), p < .001. Compared with nursing homes, more patients in home nursing services used cardiovascular drugs and fewer patients used psychotropic drugs. Altogether, 8615 drug-drug interactions were identified in 55% of patients, 48% in nursing homes and 57% in home nursing services, p < .001.

CONCLUSIONS

There are significant differences in the quality of drug prescribing in nursing homes compared with home nursing services. Explanations as to why these differences exist need to be further explored.

The NSAID dilemma: managing osteoarthritis in high-risk patients

For decades, evidence-based data and reported experience have warned that the common chronic oral nonsteroidal anti-inflammatory drug (NSAID) therapy for osteoarthritis (OA) in elderly patients is ultimately dangerous. Elderly patients with OA are at heightened risk for developing serious gastrointestional and cardiovascular adverse events, including gastrointestinal bleeding, myocardial infarction, and stroke. Prescribing NSAIDs, especially in an elderly population, continues to be discouraged because of these significant risks. A dilemma exists for individuals who need the established efficacy associated with oral NSAIDs but who are at increased risk for serious adverse events associated with these agents. The goal of this clinical review was to evaluate the risks versus benefits of current options in the treatment of OA. This review found that topical NSAIDs seem to be the safest choice among all options to mitigate gastrointestinal and cardiovascular risks and should be considered prior to the initiation of oral nonselective or cyclooxygenase (COX)-2-selective NSAIDs for individuals presenting with a localized expression of OA. Further research is needed to evaluate and compare these therapies in treating both pain and inflammation effectively while mitigating safety risks in high-risk populations.

Polypharmacy, aging and potential drug-drug interactions in outpatients in Taiwan: a retrospective computerized screening study

BACKGROUND

Polypharmacy is common in outpatients and has been identified as a major risk factor for drug-drug interactions (DDIs), which are an important cause of adverse drug reactions. There has been a rapid increase in the number of elderly patients worldwide. However, there have been few studies quantifying the impact of both patient age and the number of concomitant drugs prescribed on the probability of potential DDIs per person in general outpatients.

OBJECTIVE

To assess the extent to which polypharmacy and aging are associated with potential DDIs in outpatients at a medical centre in Taiwan.

METHODS

The medications of 81,650 outpatients who visited a medical centre in Taiwan between January 2004 and March 2004 were retrospectively screened for potential DDIs using a computerized drug-interaction program. The main inclusion criteria were a minimum of two drug prescriptions and duration of use of 14 or more days. We also analysed the DDI pattern, which included severity, level of documentation and onset of potential DDIs, and assessed the impact of the number of drugs prescribed and of aging on the prevalence of potential DDIs per person.

RESULTS

The prevalence of potential DDIs was 25.6% (20,902 of 81,650). The mean ± SD age of the 20,902 patients with potential DDIs was 57.5 ± 16.5 years, and 47.6% of these patients were male. The mean ± SD number of prescribed drugs in patients with potential DDIs was 5.8 ± 2.4, and 67.7% of these patients were prescribed more than four drugs. The majority (55.7%) of DDIs were of the C2 pattern (severity: moderate; documentation: probable). The prevalence of potential DDIs increased in a linear mode with increasing age (p < 0.001) and with the number of drugs prescribed (p < 0.001); furthermore, in addition to being independently associated with potential DDIs, these two factors interacted to increase the risk further.

CONCLUSIONS

This study showed that approximately one-quarter of 81,650 outpatients who visited a medical centre in Taiwan over a period of 3 months in 2004 had potential DDIs. We observed independent increases in potential DDIs per person in association with aging and increasing number of prescribed drugs. Furthermore, a significant interaction between these two factors was observed: the effect of aging on the prevalence of potential DDIs increased as the number of prescribed drugs increased. Potential DDIs in outpatients can be reduced by minimizing the number of drugs prescribed following careful consideration of both their benefits and risks, particularly in the aging population.

Identifying adverse drug reactions associated with drug-drug interactions: data mining of a spontaneous reporting database in Italy

BACKGROUND

Drug-drug interactions (DDIs) are an important cause of adverse drug reactions (ADRs). Many studies have recently considered this issue, but most of them focus only on potential interactions and are often related to the hospital setting. A spontaneous reporting database could be a valuable resource for detection of ADRs associated with DDIs; however, data in the literature are limited.

OBJECTIVE

To detect those patients treated with potentially interacting drugs and the cases where reported adverse reactions are a possible consequence of DDIs, using an Italian spontaneous reporting database.

METHODS

The data were obtained from a database containing all reports of suspected ADRs from five Italian regions (January 1990 to December 2007) that are the main contributors to the Italian spontaneous reporting system. All reports containing at least two drugs, reported as being suspected of causing the ADR or as concomitant medication, were selected and a list of drug pairs was drawn up. We performed a search to verify which drug pairs are considered a potential DDI, using the Internet version of the DRUGDEX(R) system. For each report containing a potential DDI, we verified whether the description of the adverse reaction corresponded to the interaction effect.

RESULTS

The database contained 45 315 reports, of which 17 700 (39.1%) had at least two reported drugs. We identified 5345 (30.2%) reports with potential DDIs, and in 1159 (21.7%) of these reports a related ADR was reported. The percentage of reports with potential DDIs increased in relation to the number of concomitantly administered drugs, ranging from 9.8% for two drugs to 88.3% for eight or more drugs. The percentages of serious or fatal reports of ADRs associated with a DDI were significantly higher than other reports analysed. The mean age, percentage of male patients and the mean number of drugs were also significantly higher in reports with DDIs than in other reports. In 235 of 1159 reports (20.3%), both interacting drugs were recognized as suspect by the reporter. This percentage varies in relation to the drugs involved, ranging from 2% to about 65%. The most frequently reported interaction was digoxin and diuretics, but no fatal ADRs were reported with this combination. The combination of anticoagulant and antiplatelet agents was responsible for the greatest number of serious reactions and deaths.

CONCLUSIONS

This study validates that spontaneous reporting, despite its limitations, can be an important resource for detecting ADRs associated with the concomitant use of interacting drugs. Moreover, our data confirm that DDIs could be a real problem in clinical practice, showing that more than one in five patients exposed to a potential DDI experienced a related ADR.

Changes in under-treatment after comprehensive geriatric assessment: an observational study

BACKGROUND

Under-treatment is frequently present in geriatric patients. Because this patient group often suffer from multiple diseases, polypharmacy (defined as the concomitant chronic use of five or more drugs) and contraindications to indicated drugs may also frequently be present.

OBJECTIVE

To describe the prevalence of under-treatment with respect to frequently indicated medications before and after comprehensive geriatric assessment (CGA) and the prevalence of contraindications to these medications.

PATIENTS AND METHODS

The geriatric outpatients evaluated in this study had previously been included in a prospective descriptive study conducted in 2004. Demographic data, medical history, co-morbidity and medication use and changes were documented. The absence of drugs indicated for frequently under-treated conditions before and after CGA was compared. Under-treatment was defined as omission of drug therapy indicated for the treatment or prevention of 13 established diseases or conditions known to be frequently under-treated. Co-morbid conditions were independently classified by two geriatricians, who determined whether or not a condition represented a contraindication to use of these drugs.

RESULTS

In 2004, 807 geriatric outpatients were referred for CGA. Of these, 548 patients had at least one of the 13 selected diseases or conditions. Thirty-two of these patients were excluded from the analysis, leaving 516 patients. Before CGA, 170 of these patients were under-treated (32.9%); after CGA, 115 patients (22.3%) were under-treated. Contraindications were present in 102 of the patients (19.8%) and were more frequent in under-treated patients. After CGA, mean drug use and the prevalence of polypharmacy increased. Although 393 drugs were discontinued after CGA, the overall number of drugs used increased from 3177 before CGA to 3424 after CGA. Five times more drugs were initiated for a new diagnosis than for correction of under-treatment.

CONCLUSIONS

Under-treatment is significantly reduced after CGA. Patients with contraindications to indicated medicines are more frequently under-treated. CGA leads to an increase in polypharmacy, mainly because of new conditions being diagnosed and despite frequent discontinuation of medications.

[A hazard scale for severe interactions: a tool for establishing prioritising strategies to improve the safety of the prescription in family medicine]

OBJECTIVE

To effectively locate the drugs most implicated in severe interactions as a basis of designing actions to improve patient safety in Primary Care.

DESIGN

Cross-sectional study of prescriptions using the Primary Care computerised medical records database (OMI-PC).

SETTING

Murcia (Spain) Health Areas I, VI, VII and IX (723,664 inhabitants).

PARTICIPANTS

There are 362,271 patients over 14 years-old available in the OMI-PC and are assigned to a doctor who uses the OMI-PC regularly.

MAIN MEASUREMENTS

We analysed the drugs that each patient could be taking, looking for severe interactions. We constructed a severe interaction hazard scale (e-PIG) calculating [1] the probability that a non-selected patient may be taking a particular drug and [2] the probability that a drug may produce a severe interaction. With this, we estimated the risk of producing a severe interaction for each drug, which was converted into a 5 point logarithmic scale.

RESULTS

We found 83,138 patients (22.9%) at risk (they took 2 or more drugs). We identified 466,940 prescriptions providing 939 drugs and 5,597 severe interactions (prevalence 5.8%). In these, 167 drugs were involved, of which e-PIG identified 5 (3%) with an extreme value: omeprazole, diazepam, acenocoumarol, ibuprofen and calcium.

CONCLUSIONS

e-PIG is a logarithmic expression of the risk that prescribing a particular drug may produce a severe interaction in a determined setting and time. Its monitoring could become a prioritisation element that may assist the design of strategies for improving the safety of the use of drugs.

Geriatric drug therapy: neglecting the inevitable majority

Demographic evolution will considerably increase the number of people aged 65 years and beyond in the coming decades. The elderly not only represent the most heterogeneous population, but also are a major user group for prescribed medicines, a predominance that will continue to further increase. Medicines and medication management are much more complex and challenging in the elderly and can only be addressed through a multidisciplinary approach. There is strong evidence that the elderly are able to properly manage their medication; however, their medications require different features than the standard medications used by adults. The elderly are exposed to several chronic disease conditions and their treatments, as well as experience age-related changes and limitations that need to be reflected in their medication management strategies. Geriatric drug therapy remains a multidisciplinary task. The health care industry, physicians, pharmacists, nurses and care givers provide and guide the patient's therapy according to individual needs, while the health care system and regulatory authorities build the necessary framework of support and resources.Any realistic and significant enhancement to the elderly patients' medicines and medication management needs to be addressed by all disciplines and stakeholders involved since the absence of any of the stakeholders in the overall process negatively impacts the achievable enhancement in geriatric drug therapy.

Adverse drug reactions detected by stimulated spontaneous reporting in an internal medicine department in Romania

BACKGROUND

It is generally recognized that adverse drug reactions (ADRs) represent a major concern of health systems in terms of early recognition, proper management and prevention. The aims of this study were to identify the most frequent ADRs recognized by the attending physicians, study their nature and target these ADRs in order to take future preventive measures.

METHODS

A prospective study was conducted over a 12-month period in an internal medicine department using stimulated spontaneous reporting for identifying ADRs. All ADRs reported by physicians were followed up to the patient's discharge and evaluated by an independent group of pharmacologists. Causality, severity and preventability were assessed.

RESULTS

Of the 1854 admissions, 112 ADRs in 94 patients (5.07%) were validated from the total of 118 ADRs reported. The overall incidence of serious ADRs in the hospitalized patients was 4.7%. According to the MedDRA classification, the most frequent ADRs affected the gastrointestinal system, followed by metabolic and vascular systems. The drugs most frequently involved were cardiovascular agents, anticoagulants and NSAIDs. Drug interactions were responsible for 25.9% of ADRs. According to the selected preventability scale, 40.18% ADRs were classified as 'potentially preventable' and 9.82% 'definitely preventable'. Most of the ADRs were 'type A' reactions and as such could have been avoided simply by adjusting the doses or by avoiding drug interactions.

CONCLUSIONS

Serious ADRs in hospitalized patients are common and often preventable. Preventing strategies should target drug prescription. Adequate training regarding pharmacology and optimization of drug therapy might help reduce ADRs' morbidity and mortality.

Implications of opioid analgesia for medically complicated patients

Opioid analgesics have an established role in the management of postoperative pain and cancer pain, and are gaining acceptance for the management of moderate to severe chronic noncancer pain, most notably chronic low back pain and osteoarthritis, that does not respond to other interventions. Many patients with chronic pain have co-morbid medical conditions that may complicate opioid therapy. Selecting the appropriate opioid requires knowledge of how individual opioids differ with respect to metabolism and interaction with concurrent medications, as well as the reasons why specific medical conditions may influence their efficacy and tolerability. Polypharmacy is a common complicating condition in the elderly and in patients with psychiatric illness, cancer, cardiovascular disease, diabetes mellitus or other chronic illnesses. Polypharmacy, though often necessary for patients with multiple medical conditions, also multiplies the risk of drug interactions. Pharmacokinetic drug interactions can increase or reduce exposure to the opioid or concurrent medications, reducing efficacy and/or tolerability and increasing toxicity. Pharmacodynamic interactions can enhance the depressive effects of opioids, compromising safety. Patients with impaired renal or hepatic function may have difficulty clearing or metabolizing opioids and concurrent medications, leading to increased risk of adverse events. Patients with cardiovascular, cerebrovascular or respiratory disease (including smokers of >/=2 packs/day with no other diagnosis) may be more susceptible to respiratory depression, bradycardia and hypotension with any opioid, and a few specific opioids pose additional risks. Patients with cerebrovascular disease, dementia, brain injury or psychiatric illness are more susceptible to opioid effects on the CNS, which can include euphoria, cognitive impairment and sedation. Appropriate opioid selection may mitigate these effects. Even in older patients, addiction, abuse and misdirection of prescribed opioids are of concern. Higher risk exists for patients with psychiatric illness, history of substance abuse, and identifiable substance abuse risk factors. Screening for abuse potential and vigilant patient monitoring should be routine. Opioids differ in their ability to produce euphoria, based on opioid receptor agonism, but substance abusers may be more influenced by availability, familiarity and cost factors. Consequently, opioid selection has limited influence on abuse potential but can facilitate ease of monitoring. This review provides an overview of opioid use in medically complicated patients and recommendations on how to optimize analgesia while avoiding adverse events and drug interactions in the clinical setting. Articles cited in this review were identified via a search of EMBASE and PubMed. Articles selected for inclusion discussed characteristics of specific opioids and general physiological aspects of opioid therapy in important patient populations.

Prevalence and typology of potential drug interactions occurring in primary care patients

PURPOSE

To investigate the prevalence and types of potential drug interactions in primary care patients to detect risky prescriptions as an essential condition to design intervention policies leading to an improvement in patient safety.

METHODS

Cross-sectional descriptive study.

SETTING

Two areas in Spain comprising 715,661 inhabitants.

PATIENTS

430,525 subjects with electronic medical records and assigned to a family doctor regularly updating them.

RESULTS

On a random day, 29.4% of the population was taking medication. Of these, 73.9% were at risk of suffering interactions, and these were found in 20.6% of them. The amount of interactions was higher among people with chronic conditions, the elderly, females and polymedicated patients. From the total of interactions, 55.1% belonged to the highest clinical relevance 'A' level, and 28.3% should have been avoided. The active ingredients primarily involved were hydrochlorothiazide and ibuprofen and, when focusing on those that should be avoided, omeprazole and acenocoumarol. The most frequent 'A' interaction that should be avoided was between non-conjugated excreted benzodiazepines and proton-pump inhibitors, followed by some NSAIDs and diuretics.

CONCLUSIONS

1 in 20 Spanish citizens is currently undergoing a potential drug interaction, including a high rate of clinically relevant ones that should be avoided. These results confirm the existence of a serious safety issue that should be approached and where all parties involved (physicians, health services, medical societies and patients) must do our bit to improve. Health services should foster the implementation of prescription alert systems linked with electronic medical records including clinical data.

Drug-drug interactions in general hospital and psychiatric hospital in-patients prescribed psychotropic medications

Abstract Objectives. Drug-drug interactions (DDIs) present a serious, ever increasing clinical problem. Previous studies identified DDIs among psychiatric inpatients prescribed psychotropics, but none have focused on psychotropics prescribed to General Hospital inpatients. This study aimed to identify: putative drug-drug interactions; mechanisms; potential seriousness among patients prescribed psychotropes in both psychiatric and general hospital inpatients settings. We hypothesised that potential interactions per person would be greater in General Hospital inpatients on psychotropics, due to polypharmacy. Method. We surveyed psychotropic prescribing in hospital wards in a public sector mental health organisation and a 500-bed general hospital. Ward pharmacists collected drug prescription data. A computer based protocol evaluated DDIs. Results. A total of 7.4% of General Hospital inpatients and 100% of Psychiatric Unit inpatients surveyed were prescribed psychotropic medication. The General Hospital group had significantly more potential interactions per person (3.0) than Psychiatric inpatients (1.3) (P<0.05). There were significantly more potentially serious interactions in the general hospital group (P<0.025). Conclusions. DDIs affect those prescribed psychotropics in both General and Psychiatric Hospitals. The General Hospital patients had a higher number per person and more serious potential interactions, yet are often poorly served by psychiatric services, suggesting that liaison psychiatrists have a role in physician education and DDI assessment.

Registered nurses' medication management of the elderly in aged care facilities

BACKGROUND

Data on adverse drug reactions (ADRs) showed a rising trend in the elderly over 65 years using multiple medications.

AIM

To identify registered nurses' (RNs) knowledge of medication management and ADRs in the elderly in aged care facilities; evaluate an education programme to increase pharmacology knowledge and prevent ADRs in the elderly; and develop a learning programme with a view to extending provision, if successful.

METHOD

This exploratory study used a non-randomized pre- and post-test one group quasi-experimental design without comparators. It comprised a 23-item knowledge-based test questionnaire, one-hour teaching session and a self-directed learning package. The volunteer sample was RNs from residential aged care facilities, involved in medication management. Participants sat a pre-test immediately before the education, and post-test 4 weeks later (same questionnaire). Participants' perceptions obtained.

FINDINGS

Pre-test sample n = 58, post-test n = 40, attrition rate of 31%. Using Microsoft Excel 2000, descriptive statistical data analysis of overall pre- and post-test incorrect responses showed: pre-test proportion of incorrect responses = 0.40; post-test proportion of incorrect responses = 0.27; Z-test comparing pre- and post-tests scores of incorrect responses = 6.55 and one-sided P-value = 2.8E-11 (P < 0.001).

CONCLUSION AND IMPLICATIONS

Pre-test showed knowledge deficits in medication management and ADRs in the elderly; post-test showed statistically significant improvement in RNs' knowledge. It highlighted a need for continuing professional education. Further studies are required on a larger sample of RNs in other aged care facilities, and on the clinical impact of education by investigating nursing practice and elderly residents' outcomes.

Development of CRIteria to assess appropriate Medication use among Elderly complex patients (CRIME) project: rationale and methodology

Pharmacological treatment of complex older adults with comorbidities, multiple impairments in function, cognition, social status and geriatric syndromes represents a challenge for prescribing physicians and often results in a high rate of iatrogenic illnesses. Clinical guidelines are commonly used to indicate appropriate prescription, but they are often based on the results of clinical trials that are conducted on young subjects with a low level of complexity. Therefore, the recommendations of clinical guidelines may be difficult to apply to older complex adults. In this paper we present the rationale and methodology of the Development of CRIteria to assess appropriate Medication use among Elderly complex patients (CRIME) project, a study aimed at producing recommendations to evaluate the appropriateness of pharmacological prescription in older complex patients, translating the recommendations of clinical guidelines to this type of patient. A literature search will be performed to integrate and revise the recommendations of disease-specific guidelines on the pharmacological treatment of patients with common chronic conditions. New recommendations will be provided and approved in a consensus meeting of international experts. Both data from randomized controlled trials and observational studies will be used to meet this aim. Recommendations provided by the CRIME project are not meant to replace existing clinical guidelines, but they may be used to help physicians in the prescribing process. Once completed these recommendations should be validated in interventional studies.

Polypharmacy in older adults with cancer

The definition of "polypharmacy" ranges from the use of a large number of medications; the use of potentially inappropriate medications, which can increase the risk for adverse drug events; medication underuse despite instructions to the contrary; and medication duplication. Older adults are particularly at risk because they often present with several medical conditions requiring pharmacotherapy. Cancer-related therapy adds to this risk in older adults, but few studies have been conducted in this patient population. In this review, we outline the adverse outcomes associated with polypharmacy and present polypharmacy definitions offered by the geriatrics literature. We also examine the strengths and weaknesses of these definitions and explore the relationships among these definitions and what is known about the prevalence and impact of polypharmacy.

Sedative load among long-term care facility residents with and without dementia: a cross-sectional study

BACKGROUND AND OBJECTIVE

People with cognitive impairment are particularly susceptible to adverse drug events linked to sedative and psychotropic drugs. A model to calculate sedative load has been developed to quantify the cumulative effect of taking multiple drugs with sedative properties. The objective of this study was to describe the sedative load and use of sedative and psychotropic drugs among long-term care facility residents with and without dementia.

METHODS

Cross-sectional data were collected from all 53 long-term care wards in Helsinki, Finland, in September 2003. Of the 1444 eligible residents, consent to participate was obtained for 1087 (75%) residents. Medication and diagnostic data were available for 1052 residents. All drugs were classified using the Anatomical Therapeutic Chemical (ATC) classification system. Sedative load was calculated for each resident using a previously published four-group model.

RESULTS

Of the 1052 residents, 781 (74.2%) were determined to have dementia. Residents with and without dementia had a similar sedative load (mean 3.0 vs 2.7, p = 0.267), but residents with dementia were taking fewer drugs than residents without dementia (mean 6.7 vs 7.4, p = 0.011). Residents with dementia were more frequent users of antipsychotics (42.8% vs 32.8%, p = 0.004), but less frequent users of antidepressants (35.6% vs 46.1%, p = 0.002) and sedative-hypnotics (22.8% vs 27.7%, p = 0.003) than residents without dementia. The most frequently used primary sedatives among people with dementia were temazepam (n = 122, 15.6%), oxazepam (n = 98, 12.5%) and lorazepam (n = 95, 12.2%). The most frequently used drugs with sedation as a prominent adverse effect or preparations with a sedating component among people with dementia were citalopram (n = 183, 23.4%), risperidone (n = 155, 19.8%) and olanzapine (n = 73, 9.3%).

CONCLUSIONS

Residents with dementia were less frequent users of sedative-hypnotic drugs than residents without dementia. However, residents with and without dementia had a similar sedative load. Clinicians should be aware of the extent to which all individual drugs, not only those prescribed for intentional sedation, contribute to a resident's sedative load. The very high rates of sedative and psychotropic use observed in long-term care facility residents highlight the need for new strategies to optimize drug use.

Potential drug-drug interactions and radiodiagnostic procedures: an in-hospital survey

OBJECTIVES

To evaluate the type, frequency, severity and predictors of potential Drug-Drug Interactions (DDIs) in a cohort of patients undergoing radiodiagnostic procedures.

SETTING

Eight Radiology wards located in Tuscany (Italy).

METHODS

All participants exposed to at least two medications were included in the analysis. DDIs were grouped according to their severity as 'minor', 'moderate' or 'major'. A logistic model was used to estimate Odds Ratios and 95% Confidence Intervals for all predictors of potential DDI.

MAIN OUTCOME MEASURES

Type and predictors of potential DDI in a cohort of patients undergoing radiodiagnostic procedures.

RESULTS

One-thousand-and-two subjects (57.6% females; mean age: 67.3 +/- 12.2) entered the analysis, and 46.1% of them incurred in a potential DDI (78.9% 'moderate' in severity). The combination of allopurinol and ACE-inhibitors was the most frequent (21/153) among major potential DDIs, while steroids were involved in all cases of potential DDI due to premedication. Co-morbidity, number of co-medications, advanced age and premedication use increased the risk of potential DDI; a protective role was found for positive history of allergy. When the analysis was restricted to subjects with premedication (n = 93), only 12.9% of them reported a potential DDI directly attributable to premedication drugs.

CONCLUSIONS

Among patients undergoing radiological examination, types and predictors of potential DDIs appeared in agreement with other kind of in-hospital populations. Premedication revealed to be a proxy predictor for potential DDIs. Considering the poor capability of the prescriber in recognizing interactions, their systematic evaluation (using an informatics tool) in patients undergoing radiological examination might be helpful in preventing the occurrence of clinically relevant DDIs.

Predicting the clinical relevance of drug interactions from pre-approval studies

Drug interactions (DIs) may result in adverse drug events that could be prevented, but in many cases the available information on potential DIs is not easily transferable to clinical practice. The majority of studies date from preclinical or premarketing phases, using animals or human-derived sources that may not accurately reflect the growing clinical complexity of high-risk populations, such as the elderly, women, children, patients with chronic disease, polytherapy and impaired organ functions. Thus, at the time of approval of a new drug the information in the summary of product characteristics refers to potential DIs, but lacks specific management recommendations and is of limited clinical utility. Therefore, we set out to review in vitro and in vivo methods to predict and quantify potential DIs, to see whether these studies could help the physician tackle daily problems of the assessment and choice of combined drug therapies, and to propose, from a clinical point of view, how premarketing studies could be improved so as to help the physician at the patient's bedside. Preclinical and premarketing study design needs to be improved to make information easily accessible and clinically transferable. Studies should also take into account appropriate sample size, duration, co-morbidity, number of coadministered drugs, within- and between-subject variability, specific at-risk populations and/or drugs with a relatively narrow therapeutic window, and clinical endpoints. After premarketing development in situations where there is potential high risk of serious adverse events, specific phase IV studies (and/or active pharmacovigilance studies) should be required to monitor and quantitatively assess their clinical impact.

[Using information technology to improve drug safety in primary care]

PURPOSE

To help family doctors to detect and prevent problems related to drug-drug interactions in order to attain a higher quality prescription and an improvement in patient safety.

METHODS

Uncontrolled study of an intervention based on quality evaluation and improvement methods.

SETTING

Two health areas in Murcia Region (Spain).

PATIENTS

Subjects appointed to 139 family doctors regularly using electronic clinical records (including doctors who were producing over 100 electronic prescriptions per week: 188,953 subjects and 334.088 prescriptions at the start, and 202,988 subjects and 335.198 prescriptions at the end of study).

INTERVENTION

(1) A software able to collect patients who had clinically important drug-drug interactions those that should be avoided (BOT I+II) was designed. (2) A report on these interactions was drawn up and delivered periodically to every single doctor, including patient identification and information on the drugs involved, possible consequences, and recommendations about what to do. (3) Clinical and educative sessions given by a trained pharmacist were carried out in doctors' health centre coinciding with their delivery.

RESULTS

Drug-drug interactions pre-intervention: prevalence 1.29%; by patient at risk 6.57%; by doctor 20.2. Post-intervention: prevalence 1.06% (improvement 17.6%, P<.000001), by patient at risk 5.17% (improvement 21.4%, P<.000001), by doctor 17.7 (improvement 12.1, P<.001).

CONCLUSIONS

Developing this technology leads to progress in patient safety, therefore it should be extended to all our family doctors. Other technologies such as an electronic alert when prescribing should be considered, particularly for either higher frequency or important consequences interactions.

Discrepancies in reported drug use in geriatric outpatients: relevance to adverse events and drug-drug interactions

BACKGROUND

Increased age is associated with polypharmacy. Polypharmacy is a risk factor for severe adverse drug reactions (ADRs) and is associated with an increased risk of mortality.

OBJECTIVES

The main goal of the current study was to describe the frequency and relevancy of discrepancies in drug use in Dutch geriatric outpatients as reported by the patients and their caregivers, documented by the referring general practitioner (GP), and registered by the public pharmacy. The frequency of medication discrepancy adverse patient events (MDAPEs) was also recorded. In addition, possible contributing factors-such as increasing age, cognitive status and depressive symptoms, the number of medications used, the number of physicians visited by the patient, and the presence of a caregiver to supervise medication use-were studied.

METHODS

This was a prospective descriptive study conducted at the geriatric outpatient clinic of a teaching hospital. Between January 1 and May 1, 2005, consecutive patients were included if they were aged >65 years, reported use of > or =1 medication, and if they could understand the goals and consequences of participating in the study. The medications described by geriatric patients and their caregivers were compared with the drugs listed by their GP. The pharmacies of the referred patients were asked to send a description of the drugs distributed in the 6 months preceding the patient's visit to the geriatric outpatient clinic. The classification of ADRs and undertreatment as clinically relevant was done by study investigators who were blinded for the presence of discrepancy.

RESULTS

A total of 120 outpatients were included. The mean (SD) age of the study patients was 82.3 (6.8) years; 71.7% were women. Of the 120 patients, 113 patients (94.2%) reported taking >1 drug and 88 (73.3%) were prescribed > or =4 drugs. At least 1 discrepancy between the medication lists of the patients, GP, or pharmacy was present in 104 of the 120 patients (86.7%). In 90 patients (75.0%), there was > or =1 discrepancy between the medication reported by the patient and the GP. Patients with > or =1 discrepancy reported taking a higher mean number of drugs and had more prescribing physicians in addition to their GP. Twenty-nine patients (24.2%) experienced an MDAPE involving the use of drugs the GP had not correctly described in the letter of referral. The pharmacy was unaware of the use of medication involved in an MDAPE in 2 patients.

CONCLUSIONS

Geriatricians should assume that the medication lists supplied by GPs are incomplete or incorrect, and be aware that in approximately 25% of patients, symptoms may be caused by medication use inaccurately described in the referral. Reports by the community pharmacy may supply valuable additional information. Because there are also discrepancies between patients and pharmacies, medication use from a database-with data from prescribing physicians and pharmacy systems-will still have to be confirmed by the patient.

[Self-medication and the elderly. The reality of the home medicine cabinet]

OBJECTIVE

To estimate the prevalence of self-medication in the elderly, to describe the characteristics of self-medication and home medicine cabinets.

DESIGN

Cross-sectional descriptive study.

SETTING

An urban primary health care (PHC) centre in Spain.

PARTICIPANTS

A total of 240 patients 75 years of age or older.

MAIN MEASUREMENTS

A structured questionnaire filled in by home care nurses from April to June 2006. Self-medication was classified into 4 sub-groups: pharmacological or herbal, exclusively pharmacological, exclusively herbal and pharmacological and herbal. The study variables were: age, sex, living alone, number of chronic diseases, number of chronic prescriptions and medicine cabinet characteristics (drugs accumulation, expired drugs, chronic drugs out of prescription, location of medicine chest and periodic review). Other variables were: drug types, source, and acute/chronic reason for self-medication.

RESULTS

Self-medication frequency was 31,2% (95% CI, 26-36), with 22.9% (95% CI, 17.5-27.5) being pharmacological and 15.4% (95% CI, 23.1-17.3), herbal. The drugs most used in self-medication were analgesics (30.9%) and cold remedies (27.2%). The pharmacy was the most usual source (49.3%). A total of 41.6% contained drugs that were out of chronic prescription, and 34.4% accumulated more than three boxes of the same medication.

CONCLUSIONS

There is a significant prevalence of self-medication among the elderly. Accumulating drugs in homes is a very extensive practice. Pharmacists and PHC professionals need to be trained in the responsible use of chronic and self-medication. Although self-care has to be encouraged, PHC professionals must make their patients aware of the harmful effects of self-medication.

Use of drugs that act on the cytochrome P450 system in the elderly

OBJECTIVES

The objective of this study was to analyze medications that act on the cytochrome P450 (CYP450) enzymatic system and are used daily by non-institutionalized elderly individuals.

METHODS

A cross-sectional population-based study of elderly individuals (> or = 60 years old) was conducted. All continuously used medications with hepatic metabolism via CYP450 that are classified as substrates, inducers or inhibitors were considered. For the analysis, elderly individuals were stratified according to age groups, and hepatic metabolism activity due to daily alcohol consumption and smoking were considered.

RESULTS

Elderly individuals (396 in total: 222 women and 174 men) between 60 and 95 years of age (mean: 72.1) were assessed. Use of drugs that act on CYP450 was identified in 61.6% of the subjects. Drug use was observed among 16.2% of the subjects: three drugs among 9.8% and four or more among 6.3% of the subjects. The metabolic activities of the drugs used were classified as substrates (58.8%), inhibitors (14.9%), and inducers (4.3%). The main drugs used were beta-blockers and statins (as substrates), proton pump inhibitors and fluoxetine (as inhibitors), and prednisone and carbamazepine (as inducers).

CONCLUSIONS

The results demonstrate that the elderly use high levels of medications that act on CYP450, thereby increasing the risk of drug interactions in a group that is already vulnerable to adverse drug effects.