Gender differences in adverse drug reactions

Sex, age, and genetics in anesthesia

PURPOSE OF REVIEW

Pharmacology is one of the corner stones of anesthesia. Outcome of anesthesia is related, in part, to both pharmacodynamics and pharmacokinetics of anesthetic drugs. Recent developments have indicated that among individuals, major differences exist in pharmacological effects. In this regard, sex, age, and genetic profile are increasingly considered to be of importance.

RECENT FINDINGS

For a number of anesthetic drugs, it has been demonstrated that sex differences influence their effects and thus can alter the outcome of anesthesia. Also other genetically determined differences than sex are important.

SUMMARY

In the future, it is expected that an individual's pharmacological needs will be based on age, sex, and genomics.

Sex differences in treatment patterns of six chronic diseases: an analysis from the German statutory health insurance

OBJECTIVE

The goal of this study was to investigate gender-specific differences in prevalence, healthcare costs, and treatment patterns in the German Statutory Health Insurance (SHI).

METHODS

The study analyzed administrative claims data of over 26 million insured with respect to prevalence and cost of illness of six chronic diseases. Insured were identified using the ATC code for medication prescription and ICD-9 code for diagnosis. The influences of gender, age, and comorbidity on cost differences were analyzed via multivariate regression analysis.

RESULTS

Adjusted for age and comorbidity, gender had a significant influence on both hospital and medication spending. Hospital costs on average were 17.1% (95% CI 14.1; 20.2) higher for men compared with women. Medication spending for men exceeded that for women on average by 13.8% (95% CI 10.9; 16.7). The diagnoses with the highest prevalence were hypertension and heart failure. Women had a higher prevalence of diabetes, coronary artery disease (CAD), heart failure, and hypertension. Medication costs were higher for men in three of five diagnoses and comparable for two diagnoses (diabetes and asthma). Women received more medication prescriptions than men, but on average prescriptions for men were 14%-26% more expensive than prescriptions for women. Regarding treatment patterns men were treated with different drug classes in cardiovascular disease (CVD) compared with women. Total medication spending stratified by diagnosis was highest for diabetes.

CONCLUSIONS

Gender differences for costs and prescribing patterns for chronic diseases vary disease specifically, but generally men had higher inpatient costs and more expensive medication prescriptions, whereas women had higher numbers of prescriptions.

Women encounter ADRs more often than do men

BACKGROUND

Several publications indicate that the female gender experiences a higher incidence of adverse drug reactions (ADRs) than does the male gender. The reasons, however, remain unclear. Gender-specific differences in the pharmacokinetic and pharmacodynamic behaviour of drugs could not be identified as an explanation. The aim of this study was to analyse ADR risk with respect to gender, age and number of prescribed drugs.

METHODS

A prospective multicenter study based on intensive pharmacovigilance was conducted. Information on patient characteristics and evaluated ADRs was stored in a pharmacovigilance database--KLASSE.

RESULTS

In 2,371 patients (1,012 female subjects), 25,532 drugs were prescribed. In 782 patients, at least one ADR was found. A multivariate regression analysis adjusting for age, body mass index (BMI) and number of prescribed drugs showed a significant influence of female gender on the risk of encountering ADRs [odds ratio (OR) 1.596, confidence interval (CI) 1.31-1.94; p < 0.0001). Dose-related ADRs (51.8%) were the dominant type in female subjects. Comparing system organ classes of the World Health Organisation (SOC-WHO), cardiovascular (CV) ADRs were particularly frequent in female subjects (OR 1.92, CI 1.15-3.19; p = 0.012).

CONCLUSION

Our data confirm the higher risk of ADRs among female subjects compared with a male cohort. Several explanations were investigated. No single risk factor could be identified.

Gender differences in pharmacological response

Female sex has been shown to be a risk factor for clinically relevant adverse drug reactions. Is the increased risk due to sex differences in pharmacokinetics, in pharmacodynamics, or did females receive more medications and higher mg/kg doses than males? Recent studies suggest that all of the above may play a role. Generally, males weigh more than females, yet few drugs are dosed based on body weight. Drug concentrations are dependent on the volume of distribution (Vd) and clearance (Cl). Both parameters are dependent on body weight for most drugs independent of sex differences. Females have a higher percent body fat than males which can affect the Vd of certain drugs. Renal clearance of unchanged drug is decreased in females due to a lower glomerular filtration. Sex differences in activity of the cytochrome P450 (CYP) and uridine diphosphate glucuronosyltransferase (UGT) enzymes and renal excretion will result in differences in Cl. There is evidence for females having lower activity of CYP1A2, CYP2E1, and UGT; higher activity of CYP3A4, CYP2A6, and CYP2B6; and no differences in CPY2C9 and CYP2D6 activity. Pharmacodynamic changes can affect both the desired therapeutic effect of a drug as well as its adverse effect profile. The most widely reported sex difference is the higher risk in females for drug-induced long QT syndrome, with two-thirds of all cases of drug-induced torsades occurring in females. Females also have a higher incidence of drug-induced liver toxicity, gastrointestinal adverse events due to NSAIDs, and allergic skin rashes. In conclusion, at the minimum, it is important to take into account size and age as well as co-morbidities in determining the appropriate drug regiment for females, as well as males. There are still large gaps in our knowledge of sex differences in clinical pharmacology and significantly more research is needed.

Sex differences in the relationship between amiodarone use and the need for permanent pacing in patients with atrial fibrillation

BACKGROUND

Amiodarone use was associated with an increased need for pacemaker insertion in a retrospective study of patients with atrial fibrillation (AF) and prior myocardial infarction. The aims of this study were to determine prospectively whether amiodarone increases the need for pacemakers in a general population of patients with AF and whether this effect is modified by sex.

METHODS

The study included 1005 patients with new-onset AF who were enrolled in the Fibrillation Registry Assessing Costs, Therapies, Adverse events, and Lifestyle (FRACTAL). Multivariable Cox regression models, including time-dependent covariates accounting for medication exposure, were used to evaluate the risk of pacemaker insertion associated with amiodarone use.

RESULTS

Amiodarone use was associated with an increased risk of pacemaker insertion (hazard ratio [HR], 2.01; 95% confidence interval [CI], 1.08-3.76) after adjustment for age, sex, atrial flutter, coronary artery disease, heart failure, and hypertension. The effect of amiodarone use was modified by sex, with a significant risk in women but not in men (HR, 4.69; 95% CI, 1.99-11.05 vs HR, 1.05; 95% CI, 0.42-2.58 [P = .02]). This interaction remained significant after adjustment for weight, body mass index, weight-adjusted amiodarone dose, and use of other antiarrhythmic or rate control drugs.

CONCLUSION

The risk of bradyarrhythmia requiring pacemaker insertion associated with amiodarone use for AF is significantly greater in women than in men, independent of weight or body mass index.

Gender differences in kidney function

Sex hormones influence the development of female (F) and male (M) specific traits and primarily affect the structure and function of gender-specific organs. Recent studies also indicated their important roles in regulating structure and/or function of nearly every tissue and organ in the mammalian body, including the kidneys, causing gender differences in a variety of characteristics. Clinical observations in humans and studies in experimental animals in vivo and in models in vitro have shown that renal structure and functions under various physiological, pharmacological, and toxicological conditions are different in M and F, and that these differences may be related to the sex-hormone-regulated expression and action of transporters in the apical and basolateral membrane of nephron epithelial cells. In this review we have collected published data on gender differences in renal functions, transporters and other related parameters, and present our own microarray data on messenger RNA expression for various transporters in the kidney cortex of M and F rats. With these data we would like to emphasize the importance of sex hormones in regulation of a variety of renal transport functions and to initiate further studies of gender-related differences in kidney structure and functions, which would enable us to better understand occurrence and development of various renal diseases, pharmacotherapy, and drug-induced nephrotoxicity in humans and animals.

Rash from Antiepileptic Drugs: Influence by Gender, Age, and Learning Disability

PURPOSE

Cutaneous adverse reactions from antiepileptic drugs (AEDs) are common, but have received little scientific attention from a clinical point of view. We wanted to study the incidence of skin reactions of current AEDs and to explore their relation to clinical parameters such as gender, age, and learning disability.

METHODS

Consecutive patients with epilepsy were studied retrospectively. A detailed survey of medical records concerning all treatment with AEDs was performed.

RESULTS

A total of 663 patients were included with altogether 2,567 exposures to 15 different AEDs. Skin reactions were found in 14% of the patients and in 5% of the exposures. Ninety-seven percent of the reactions occurred to either carbamazepine (CBZ, 11%), phenytoin (PHT, 8%), lamotrigine (LTG, 8%), oxcarbazepine (8%), or phenobarbital (2%). Skin reactions developed significantly more often in females than in males (19% vs. 8%), and significantly less often in patients with learning disability than in other patients (7% vs. 16%). These differences were significant for CBZ, PHT, and LTG when analyzed separately. Females displayed higher rash frequency during the reproductive years, while men experienced less frequent rash in the same phase of life.

CONCLUSIONS

Fertile females have a higher risk for skin reactions compared to males, probably due to hormonal factors. Patients with learning disability appeared to have a lower risk than other patients in this study. Hygiene factors may possibly be underlying.

A systematic review of the quality of homeopathic pathogenetic trials published from 1945 to 1995

BACKGROUND

The quality of information gathered from homeopathic pathogenetic trials (HPTs), also known as 'provings', is fundamental to homeopathy. We systematically reviewed HPTs published in six languages (English, German, Spanish, French, Portuguese and Dutch) from 1945 to 1995, to assess their quality in terms of the validity of the information they provide.

METHODS

The literature was comprehensively searched, only published reports of HPTs were included. Information was extracted by two reviewers per trial using a form with 87 items. Information on: medicines, volunteers, ethical aspects, blinding, randomization, use of placebo, adverse effects, assessments, presentation of data and number of claimed findings were recorded. Methodological quality was assessed by an index including indicators of internal and external validity, personal judgement and comments of reviewers for each study.

RESULTS

156 HPTs on 143 medicines, involving 2815 volunteers, produced 20,538 pathogenetic effects (median 6.5 per volunteer). There was wide variation in methods and results. Sample size (median 15, range 1-103) and trial duration (mean 34 days) were very variable. Most studies had design flaws, particularly absence of proper randomization, blinding, placebo control and criteria for analysis of outcomes. Mean methodological score was 5.6 (range 4-16). More symptoms were reported from HPTs of poor quality than from better ones. In 56% of trials volunteers took placebo. Pathogenetic effects were claimed in 98% of publications. On average about 84% of volunteers receiving active treatment developed symptoms. The quality of reports was in general poor, and much important information was not available.

CONCLUSIONS

The HPTs were generally of low methodological quality. There is a high incidence of pathogenetic effects in publications and volunteers but this could be attributable to design flaws. Homeopathic medicines, tested in HPTs, appear safe. The central question of whether homeopathic medicines in high dilutions can provoke effects in healthy volunteers has not yet been definitively answered, because of methodological weaknesses of the reports. Improvement of the method and reporting of results of HPTs are required.

REFERENCES

References to all included RCTs are available on-line at.

Gender differences in aspirin use among adults with coronary heart disease in the United States

BACKGROUND

Aspirin reduces mortality for men and women with coronary heart disease (CHD). Previous research suggests women with acute coronary syndromes receive less aggressive care, including less frequent early administration of aspirin. The presence of gender differences in aspirin use for secondary prevention is less clear.

OBJECTIVE

To determine if a gender difference exists in the use of aspirin for secondary prevention among individuals with CHD.

DESIGN

We analyzed data from the nationally representative 2000-2002 Medical Expenditure Panel Surveys to determine the prevalence of regular aspirin use among men and women with CHD.

PARTICIPANTS

Participants, 1,869, 40 years and older who reported CHD or prior myocardial infarction.

RESULTS

Women were less likely than men to use aspirin regularly (62.4% vs 75.6%, p < .001) even after adjusting for demographic, socioeconomic and clinical characteristics (adjusted OR = 0.62, 95% CI, 0.48-0.79). This difference narrowed but remained significant when the analysis was limited to those without self-reported contraindications to aspirin (79.8% vs 86.4%, P = .002, adjusted OR = 0.68, 95% CI, 0.48-0.97). Women were more likely than men to report contraindications (20.5% vs 12.5%, P < .001). Differences in aspirin use were greater between women and men with private health insurance (61.8% vs 79.0%, P < .001, adjusted OR = 0.48, 95% CI, 0.35-0.67) than among those with public coverage (62.5% vs 70.7%, P = .04, adjusted OR = 0.74, 95% CI, 0.50-1.11) (P < .001 for gender-insurance interaction).

CONCLUSION

We found a gender difference in aspirin use among patients with CHD not fully explained by differences in patient characteristics or reported contraindications. These findings suggest a need for improved secondary prevention of cardiovascular events for women with CHD.

Diagramming patients' views of root causes of adverse drug events in ambulatory care: an online tool for planning education and research

OBJECTIVE

Diagram patients' views of the causes of adverse drug events (ADEs) in ambulatory care, examine characteristics of causes reported by patients, and identify those that have been studied in the medical and social science literatures.

METHODS

Twenty-two primary care patients were interviewed using a root cause analysis approach. Diagrams derived from interviews were consolidated and displayed online as a composite interactive causal diagram. Patient-reported causes were compared to evidence in the social science and medical literatures.

RESULTS

Patients ascribed 164 causes to ADEs occurring through eight major pathways, including medication nonadherence, prescriber-patient miscommunication, patient medication error, failure to read medication label/insert, polypharmacy, patient characteristics, pharmacist-patient miscommunication, and self medication. Most frequently reported causes were intrapsychic and interpersonal in nature. Most patient-reported causes have been studied, however, several practical and motivational antecedents lack research.

CONCLUSION

Conducting root cause analysis with patients reveals multiple logically linked aspects of medication safety in community settings that merit further research and consideration in patient and prescriber education.

PRACTICE IMPLICATIONS

This causal diagram provides a broadly accessible planning tool for reducing ambulatory ADEs by showing a comprehensive picture of potential causes, identifying causal factors supported by evidence, and disclosing likely consequences of change efforts. Also, patient-centered medication safety strategies should address psychological and practical barriers patients face in their everyday lives.

Physician and patient factors associated with the prescribing of medications for sleep difficulties that are associated with high abuse potential or are expensive: an analysis of data from the National Ambulatory Medical Care Survey for 1996-2001

OBJECTIVE

This study evaluated the association between various socioeconomic and clinical factors relating to patients and physicians and the prescribing of medications that have a high abuse potential or are expensive for the treatment of sleep difficulties in a nationally representative sample of outpatient physician visits in the United States.

METHODS

This cross-sectional study used data from the National Ambulatory Medical Care Survey from 1996-2001. Patients aged > or =18 years who received treatment for sleep difficulties in US outpatient settings over this period were included in the study sample. Office visits were considered related to insomnia/sleep difficulties if relevant International Classification of Diseases, Ninth Revision, diagnosis codes were recorded and if insomnia was reported as the reason for the visit or any medication with a primary indication for insomnia was prescribed. Medications associated with dependence and withdrawal symptoms were categorized as having a high abuse potential. Medications were considered expensive if the average wholesale price of 100 tablets was > or =$150 (ie, the 75th percentile of the total cost of all medications prescribed for sleep disorders only). The data were subjected to multivariate logistic regression analysis.

RESULTS

From 1996 through 2001, 2966 unweighted patient visits for insomnia/sleep difficulty were identified, representing approximately 94.6 million weighted observations in the overall US population; pharmacotherapy only was prescribed at 48% (45 million) of these visits. Medications with abuse potential were prescribed at 53% (24 million) of visits. Among visits at which pharmacotherapy was prescribed, visits by male patients were 39% less likely than visits by female patients to result in a prescription for a medication with abuse potential (odds ratio [OR] = 0.61; 95% CI, 0.45-0.81). Visits by patients with psychiatric comorbidities were 80% more likely to be associated with receipt of a prescription for a medication with abuse potential than were visits by patients with no such comorbidities (OR = 1.80; 95% CI, 1.31-2.47). Expensive medications were prescribed at 25% (15 million) of visits involving some pharmacotherapy. Patients aged > or =65 years were 44% less likely to receive a prescription for an expensive medication than was the reference group, patients aged 18 to 34 years (OR = 0.56; 95% CI, 0.35-0.90). Hispanic patients were 56% less likely to receive a prescription for an expensive medication than were non-Hispanic patients (OR = 0.44; 95% CI, 0.22-0.88).

CONCLUSIONS

This study found an increased probability of female patients with sleep difficulties receiving a medication with high abuse potential in outpatient settings in the United States from 1996 through 2001. In addition, there was a possible association between the age and ethnicity of patients with insomnia/sleep difficulties and the prescribing of expensive medications for sleep difficulties.

Cardiovascular drug therapy in women

Cardiovascular disease has been the leading cause of morbidity and mortality in American women; yet, until recently, there was no mandate to specifically include women in clinical trials of the major cardiovascular drugs. Despite new regulations, there is still a lack of readily available data for the clinician to use when planning drug therapy for women, as many of the drugs in use today were developed and tested prior to the new regulations being in effect. The purpose of this article is to provide advanced practice nurses with the most current information on the use of cardiovascular drugs in women. Information on the unique biological features of women is first presented to provide background material for subsequent sections. This is followed by an explanation of pharmacokinetic processes in women to include information on absorption, distribution, and clearance of drugs. A brief review of the effects of the phases of the menstrual cycle on drug therapy is given and then issues related to the profound physiologic changes in pregnancy and subsequent effects on drug therapy are reviewed. An analysis of the strength of the available evidence on drug therapies in women from the major trials on acute coronary syndromes, heart failure, dyslipidemia, atrial fibrillation, and hypertension is provided. Finally, implications for practice, including recommendations for drug prescription, are summarized.

Adverse events among patients in a behavioral treatment trial for heroin and cocaine dependence: effects of age, race, and gender

Safety monitoring is a critical element of clinical trials evaluating treatment for substance dependence, but is complicated by participants' high levels of medical and psychiatric comorbidity. This paper describes AEs reported in a large (N = 286), 29-week outpatient study of behavioral interventions for heroin and cocaine dependence in methadone-maintained outpatients. A total of 884 AEs were reported (3.1 per patient, 0.12 per patient-week), the most common being infections (26.8%), gastrointestinal (20.5%), musculoskeletal (12.3%), and general (10%) disorders. Serious AEs were uncommon (1.6% of total). Female participants reported significantly higher rates of AEs (incidence density ratio, IDR = 1.38, p < 0.0001); lower rates of AEs were reported by African Americans (IDR = 0.73, p<0.0001) and participants over age 40 reported lower rates of AEs (IDR = 0.84, p = 0.0095). AE incidence was not associated with the study intervention or with psychiatric comorbidity. Further work is needed to adapt AE coding systems for behavioral trials for substance dependence; the standard Medical Dictionary for Regulatory Activities, International Federation of Pharmaceutical Manufacturers Associations (MedDRA) coding system used in this report did not contain a separate category for one of the most common types of AE, dental problems. Nonetheless, the data reported here should help provide a context in which investigators and IRBs can interpret the patterns of AEs they encounter.

Gender-specific expression of liver organic anion transporters in rat

BACKGROUND

Sex differences in drug pharmacokinetics have been well recognized and gender has been considered a risk factor for adverse events to medications. The aim of this study was to investigate the effect of gender on the expression of hepatocellular transport proteins involved in uptake and secretion of organic anions in rat.

MATERIALS AND METHODS

Expression of the rat liver organic anion transporting polypeptides (Oatps) and multidrug resistance proteins (Mrps) was analysed by reverse transcription polymerase chain reaction (RT-PCR), immunoblot analysis and immunofluorescence microscopy in male and female rats. Regulation of these transport proteins in response to the steroid dehydroepiandrosterone (DHEA) was investigated.

RESULTS

In untreated rats, protein expression significantly differed between genders being higher (Mrp2, Mrp3), comparable [Oatp1a1 (Oatp1); Oatp1b2 (Oatp4)] or lower [Oatp1a4 (Oatp2)] in female than in male rat. DHEA treatment over 3 days (100 mg d(-1)) led to a further increase in Mrp3 expression only in female rats. Mrp2 expression was not influenced by DHEA treatment. Oatp1a1 and Oatp1b2 were significantly down-regulated after DHEA treatment in both male and female rats. In contrast, Oatp1a4 was down-regulated in male rats only.

CONCLUSIONS

In rat, liver transport proteins of the Oatp and Mrp family are expressed and regulated in a gender-specific manner according to sexual differences in the hepatic metabolism of steroids and drugs. These findings may partly explain the well-known sex differences in hepatic handling of organic anions.

Hydrochlorothiazide-Induced Noncardiogenic Pulmonary Edema: An Underrecognized Yet Serious Adverse Drug Reaction

Noncardiogenic pulmonary edema is a rare but potentially life-threatening complication of hydrochlorothiazide therapy. We describe three patients who developed this serious adverse reaction. A 64-year-old woman developed dypsnea and hypotension within 60 minutes of taking a single dose of hydrochlorothiazide 25 mg. She was admitted to the critical care unit with acute respiratory failure and subsequent multiple-organ dysfunction. The second patient was a 56-year-old woman who experienced sudden onset of shortness of breath that developed 10 minutes after taking a single dose of hydrochlorothiazide 25 mg. The third was a 59-year-old woman who developed sudden onset of shortness of breath, nausea, vomiting, and diarrhea after her first dose of hydrochlorothiazide-triamterene. All three women had a history of a similar, albeit minor, reaction to a thiazide diuretic. Review of the literature identified 36 additional cases of noncardiogenic pulmonary edema after thiazide use. The patients developed symptoms 10-150 minutes after ingestion of hydrochlorothiazide or another thiazide. Symptoms can occur on first exposure to the drug or in patients taking the drug intermittently. Of interest, 90% of documented cases occurred in women. With the increasing use of thiazide diuretics in the treatment of hypertension, clinicians need to be aware of the possible association of these drugs with the development of noncardiogenic pulmonary edema.

Epidemiology, Comparative Methods of Detection, and Preventability of Adverse Drug Events

BACKGROUND

Adverse drug events (ADEs) continue to be of concern to all health professionals. Even serious ADEs are underreported in all patient-care environments.

OBJECTIVE

To discover the incidence and the best detection methods and preventability for ADEs at Al Qassimi Hospital, a 360-bed facility in the United Arab Emirates.

METHODS

During the first and fourth quarters of 2003, data collection for ADEs was limited to spontaneous reporting. During the second and third quarters, active monitoring for ADEs took place in the adult, pediatric medical, and intensive care wards. ADEs were assessed for causality using the Naranjo algorithm and for severity and preventability. The incidence of ADEs was calculated and the detection methods were compared.

RESULTS

The incidence of ADEs detected through surveillance was significantly higher (p < 0.001) than for ADEs reported spontaneously for both inpatients (3.592 vs 0.068/100 patient days) and outpatients (0.299 vs 0.022/100 patient visits). Most ADEs were judged to be of mild to moderate severity. About 56% of ADEs were judged definite or probable and, of these, 13.8% were consistently judged preventable. The most prevalent drugs implicated were central nervous system (23.6%), antiinfective (17.1%), and cardiovascular (16.5%) agents. The best ADE detection method was using physicians' notes.

CONCLUSIONS

Active surveillance for ADEs, with the aid of ADE trigger alerts, yields a significantly higher number of reports than spontaneous reporting. Such surveillance is useful in identifying areas where improvements in the safe use of drugs can be made.

Sex and racial differences in pharmacological response: where is the evidence? Pharmacogenetics, pharmacokinetics, and pharmacodynamics

The Food and Drug Administration (FDA) reviewed 300 new drug applications between 1995 and 2000. Of the 163 that included a sex analysis, 11 drugs showed a >40% difference in pharmacokinetics between males and females, which was listed on the product label, yet no dosing recommendations were made based on sex. Female sex has been shown to be a risk factor for clinically relevant adverse drug reactions. Would simply dosing females based on their different pharmacokinetics decrease the incidence of adverse events? The answer is not known. Sex-dependent pharmacodynamic effects have been identified. The role of pharmacokinetics vs. pharmacodynamics is unclear, as is the impact of pharmacogenetics on both. This review highlights a few specific examples in each area in which sex differences in pharmacokinetics and pharmacodynamics are important and provides recommendations for additional needed research.

Socio-demographic factors related to the prevalence of adverse drug reaction at hospital admission in an elderly population

To identify and to measure the association between socio-demographic factors and the prevalence of adverse drug reaction at hospital admission in an elderly population, we carried out a cross-sectional study on a sample of 19,070 patients of the Gruppo Italiano di Farmacoepidemiologia nell'Anziano data base (Italy). The following socio-demographic variables were considered as independent variables: gender, age, education, living arrangement, widowhood/widowerhood, and alcohol and tobacco habit. We estimated the association of these variables with diagnosis of any adverse drug reaction at hospital admission. We used a logistic regression model to obtain estimates of this association, taking into account hepatic and renal diseases, number of diseases, number of drugs used, albumin index (indicator of nutritional condition) and cognitive function. Out of the 19,070 patients included in our study, 878 (4.3%) were diagnosed with an adverse drug reaction at admission. The multivariate analysis shows that none of the socio-demographic variables and health habits considered are associated with adverse drug reactions at admission. A worse nutritional condition of the subject (OR = 1.39; 95% CI: 1.17-1.64), the number of drugs consumed in the month previous to the admission (OR = 1.74; 95% CI: 1.47-2.08) and the presence of renal disease (OR = 1.76; 95% CI: 1.41-2.55) are associated with ADR at hospital admission. Our results suggest that special attention should be paid to avoid adverse drug reactions in elderly people with nutritional problems, renal failure or those who are using two drugs or more. Additional precautions should be taken with people with cognitive impairment, because of their reduced capacity to report their symptoms.

Effect of a Simple Dose-Escalation Schedule on Tramadol Tolerability

OBJECTIVE

To assess the effect of a very simple dose-escalation schedule on tramadol tolerability in clinical practice. This schedule consists of starting treatment with sustained-release tramadol 50mg twice daily, and escalating the dose around 7 days later to 100mg twice daily.

METHODS

Data from 1925 outpatients with non-malignant chronic pain were collected in this multicentre, prospective, comparative, non-randomised, open, observational study.

RESULTS

A total of 1071 patients (55.6%) were included in the dose-escalation group (50mg group) and 854 patients (44.4%) in the control group (sustained-release tramadol 100mg twice daily; 100mg group). The proportion of patients who interrupted tramadol treatment due to the occurrence of adverse reactions was significantly lower in the 50mg group (5.6%) than in the 100mg group (12.6%) [p = 0.001]. In line with this, the proportion of patients who experienced at least one adverse reaction was significantly lower in the 50mg group (18.4%) than in the 100mg group (30.4%) [p = 0.001] and, interestingly, the two most frequently reported adverse reactions, nausea and dizziness, were found with a significantly lower frequency in the 50mg group (p < 0.001). Multivariate analysis showed that the risk of safety-related treatment cessations was 2.3 times higher in the 100mg group than in the 50mg group, and 2.2 times higher in females than in males. The two treatments were equally effective in reducing pain intensity (p = 0.121), measured as a reduction in pain score obtained by means of a visual analogue scale.

CONCLUSION

The instauration of tramadol treatment, starting with sustained-release 50mg capsules twice daily and escalating the dose some days later to 100mg twice daily, was shown to be an effective and easy way to improve tramadol tolerability in clinical practice, whilst maintaining its analgesic efficacy.

A meta-analysis of randomized controlled studies on the effects of extended-release niacin in women

The present meta-analysis pooled data from 5 double-blind, placebo-controlled studies in 432 patients with dyslipidemia treated with various doses of extended-release niacin. Data were analyzed for possible gender differences in response to treatment. At all doses, mean decreases in low-density lipoprotein cholesterol were greater in women than in men; differences were significant at doses of 1,000 mg (6.8% vs 0.2%, p = 0.006), 1,500 mg (11.3% vs 5.6%, p = 0.013), 2,000 mg (14.8% vs 6.9%, p = 0.010), and 3,000 mg (28.7% vs 17.7%, p = 0.006). Decreases in triglyceride levels also tended to be greater in women than in men but reached significance only at the 1,500-mg dose (28.6% vs 20.4%, p = 0.040). No similar trends or significant gender differences were noted in levels of lipoprotein(a) and high-density lipoprotein cholesterol. This meta-analysis confirms that women respond as well as men, and possibly slightly better, to treatment with extended-release niacin and that it is a safe and effective treatment option for women with dyslipidemia.

Adverse drug reactions as cause of hospital admissions: results from the Italian Group of Pharmacoepidemiology in the Elderly (GIFA)

OBJECTIVES

To determine the prevalence of adverse drug reaction (ADR)-related hospital admissions in an older population, to describe the most common clinical manifestations and drugs most frequently responsible for ADR-related hospital admissions, and to identify independent factors predictive of these ADRs.

DESIGN

Multicenter pharmacoepidemiology survey conducted between 1988 and 1997.

SETTING

Eighty-one academic hospitals throughout Italy.

PARTICIPANTS

Twenty-eight thousand four hundred eleven patients consecutively admitted to participating centers during the survey periods.

MEASUREMENTS

For each suspected ADR at admission, a physician, who coded description, severity, and potentially responsible drugs, completed a questionnaire.

RESULTS

Mean age +/- standard deviation of the patients was 70 +/- 16. One thousand seven hundred four ADRs were identified upon hospital admission. In 964 cases (3.4% of all admissions), ADRs were considered to be the cause of these hospital admissions. Of these, 187 ADRs were coded as severe. Gastrointestinal complaints (19%) represented the most common events, followed by metabolic and hemorrhagic complications (9%). The drugs most frequently responsible for these ADRs were diuretics, calcium channel blockers, nonsteroidal antiinflammatory drugs, and digoxin. Female sex (odds ratio (OR) = 1.30, 95% confidence interval (CI) = 1.10-1.54), alcohol use (OR = 1.39, 95% CI = 1.20-1.60), and number of drugs (OR = 1.24, 95% CI = 1.20-1.27 for each drug increase) were independent predictors of ADR-related hospital admissions. For severe ADRs, age (OR = 1.50, 95% CI = 1.01-2.23 for age 65-79 and OR = 1.53, 95% CI = 1.00-2.33 for age > or =80, respectively), comorbidity (OR = 1.12, 95% CI = 1.05-1.20 for each point in the Charlson Comorbidity Index), and number of drugs (OR = 1.18, 95% CI = 1.11-1.25 for each drug increase) were the only predisposing factors.

CONCLUSIONS

The most important determinant of risk for ADR-related hospital admissions in older patients is number of drugs being taken. When considering only severe ADRs, risk is also related to age and frailty.

Adverse drug reactions: current issues and strategies for prevention and management

Adverse drug reactions (ADRs) are common, frequently serious and cause considerable morbidity and mortality. In addition to human costs, ADRs place considerable economic burden on society and already-stretched healthcare systems. Much work has been done to determine potential causes, commonly responsible drugs and susceptible patient groups. To this end, various national pharmacovigilance schemes exist to collate information about ADRs. Despite this, levels of ADR reporting are universally poor, with ADRs remaining a significant clinical problem. Therefore, more effective dissemination and implementation of available knowledge is needed, together with better use of the systems already in place. Local ADR centres and teams, in close liaison with national centres, appear to be an important part of this process and need to be developed within healthcare systems. In addition, there is now evidence to suggest that better use of informatics will help to facilitate this, together with wider availability of electronic notes and greater use of computer-prescribing. Although advancing technology may help to make the use of medicines safer, more effective and more specific in the future, investment to develop informatics infrastructure and local ADR teams is now needed in our healthcare systems.

Do women have more adverse drug reactions?

Up to 5% of all hospital admissions are the result of adverse drug reactions (ADRs). Identifying those factors which may predispose to ADRs is essential for risk management. Amongst the known risk factors for adverse reactions are increasing age, polypharmacy, liver and renal disease as well as being female. Female patients have a 1.5- to 1.7-fold greater risk of developing an ADR, including adverse skin reactions, compared with male patients. The reasons for this increased risk are not entirely clear but include gender-related differences in pharmacokinetic, immunological and hormonal factors as well as differences in the use of medications by women compared with men. Women generally have a lower lean body mass, a reduced hepatic clearance, have differences in activity of cytochrome P450 (CYP) enzymes (40% increase in CYP3A4, varied decrease in CYP2D6, CYP2C19 and CYP1A2), and metabolize drugs at different rates compared with men. Other important factors include conjugation, absorption, protein binding and renal elimination, which may all have some gender-based differences. However, how these differences result in an increased risk of ADRs is not clear. There are pharmacodynamic differences between men and women, seen particularly with cardiac and psychotropic medications. There is no doubt that chlorpromazine, fluspirilene and various antipsychotics appear more effective in women than men for the same dosage and plasma concentration. Similarly, women are at increased risk of QT prolongation with certain anti-arrhythmic drugs compared with men even at equivalent serum concentrations. The mechanisms are unknown. Increasingly the evidence is that idiosyncratic drug reactions, particularly cutaneous reactions, appear to have an immunological etiology. It is possible that gender difference in T cell activation and proliferation account for this as well as the increased prevalence of skin diseases such as systemic lupus erythematosus and photosensitivity. Whatever the mechanism(s), it is important to be aware that gender is a significant factor in ADRs.

Drug therapy and adverse drug reactions to terbutaline in obstetric patients: a prospective cohort study in hospitalized women

BACKGROUND: Adverse drug reactions (ADR's) could be expected more frequently in pregnant women. This study was performed in order to identify ADR's to tocolytic drugs in hospitalised pregnant women. METHODS: A prospective cohort study was performed in two General Hospitals of the Instituto Mexicano del Seguro Social (IMSS) in Mexico City. Two hundred and seven women undergoing labor, premature labor, threatened abortion or suffering any obstetric related disease were included. Drug prescription and signs and symptoms of any potential ADR were registered daily during the hospital stay. Any potential ADR to tocolytic drugs was evaluated and classified by three of the authors using the Kramer's algorithm. RESULTS: Of the 207 patients, an ADR was positively classified in 25 cases (12.1%, CI95% 8.1 to 17.5%). All ADR's were classified as minor reactions. Grouping patients with diagnosis of threatened abortion, premature labor or under labor (n= 114), 24 ADR's were related to terbutaline, accounting for a rate of 21.1 ADR's per 100 obstetric patients. Obstetric patients suffering an ADR were older than obstetric patients without any ADR. However, the former received less drugs/day x patient-1 and had a shorter hospital stay (p < 0.05) whereas the dose of terbutaline was similar between the two groups. Terbutaline inhibited uterine motility in women with and without any ADR at a similar rate, 70 and 76% respectively (x2 = 0.07; p = 0.8). CONCLUSION: Terbutaline, used as a tocolytic drug, was related to a high frequency of minor ADRs and to a high rate of effcicacy.

Task force report: future research needs for the prevention and management of immune-mediated drug hypersensitivity reactions

Immune-mediated drug hypersensitivity reactions (IDHR) have a significant impact on clinical practice, drug development, and public health. However, research to understand IDHR mechanisms and to develop diagnostic and predictive tests has been limited. To stimulate more research, a task force with representatives from the key stakeholders (research clinicians, regulatory scientists, and immunotoxicologists from the pharmaceutical industry) was assembled to identify critical data gaps and opportunities and to make recommendations on how to overcome some of the barriers to IDHR research and address research needs. It is hoped that this report will act as a springboard for future discussions and progress toward increased funding and development of organizational structures for IDHR research.

Is gender a risk factor for adverse drug reactions? The example of drug-induced long QT syndrome

Drug-induced torsade de pointes is a rare life-threatening adverse drug reaction (ADR) which is strongly influenced by gender. Drugs that prolong cardiac repolarisation include antiarrhythmics, gastrokinetics, antipsychotics, antihistamines and antibacterials. Such drugs share the potential to block cardiac voltage-gated potassium channels, particularly the rapid component (I(Kr)) of the delayed rectifier potassium current (I(K)). By doing so, such drugs usually, but not always, prolong the QT interval. Even if the electrocardiographic signs are subdued, the underlying blockade of I(Kr) current may precipitate the occurrence of arrhythmia. Women are perceived to be more prone to ADRs than men. Such a propensity may result from gender-associated differences in drug exposure, in the number of drugs prescribed (polypharmacy), in drug pharmacology, as well as from possible differences in the way the adverse event is perceived. A prolonged QT interval on the electrocardiogram (time that elapses from the onset of the cardiac ventricular depolarisation to the completion of its repolarisation) is associated with the occurrence of torsade de pointes and related ventricular arrhythmias. The QT interval is influenced by heart rate, autonomic nervous system, electrolyte disturbances and above all, drugs that block potassium channels. Two-thirds of the cases of drug-induced torsade de pointes occur in women. Therefore, this adverse effect represents a perfect example of gender differences impairing women's health. Clinical and experimental studies show that female gender is associated with a longer corrected QT interval at baseline and a greater response to drugs that block I(Kr), both of which facilitate the emergence of arrhythmia. This results most likely from a specific regulation of ionic channel expression (potassium, calcium, etc) by sex steroids, even though nongenomic effects may play a role as well. Estrogens facilitate bradycardia-induced prolongation of the QT interval and the emergence of arrhythmia whereas androgens shorten the QT interval and blunt the QT response to drugs. Hence, underlying genetic defects of potassium channels that may be asymptomatic in normal conditions, may precipitate drug-induced arrhythmia in women more frequently than in men. Even in the presence of a drug that mildly blocks I(Kr) and seldom prolongs the QT interval, women are still more prone to drug-induced torsade de pointes, due to their reduced cardiac 'repolarisation reserve'. This is an important aspect of I(Kr) blockade to be aware of during the development of new drugs.

Sex differences in nevirapine rash

Nevirapine is a nonnucleoside reverse transcriptase inhibitor (NNRTI) that has the most common treatment limiting side effect of rash. Severe rash has been observed in 3% of patients taking nevirapine in clinical trials, 85% of whom were men. In a multicenter, retrospective cohort study of all patients who received nevirapine over a 5-year period, severe rash was noted in 9 of 95 women and 3 of 263 men (risk ratio [RR], 8.31; 95% confidence interval [CI], 2.3-30.0; P=.005). Women were more likely to discontinue nevirapine therapy because of rash (RR, 4.5; 95% CI, 1. 9-10.5; P=.0005). After adjusting for age and baseline CD4 cell count in multivariate analysis, women had a 7-fold increase in risk for severe rash and were 3.5 times more likely to discontinue nevirapine therapy. In women of reproductive age for whom contraception may occur, nevirapine remains the NNRTI of choice. Recognition of sex differences in this severe adverse event will be important in prescribing nevirapine.

Drug-related problems in hospitalised patients

Drug-related problems include medication errors (involving an error in the process of prescribing, dispensing, or administering a drug, whether there are adverse consequences or not) and adverse drug reactions (any response to a drug which is noxious and unintended, and which occurs at doses normally used in humans for prophylaxis, diagnosis or therapy of disease, or for the modification of physiological function). Furthermore, adverse drug events can be defined as an injury--whether or not causally-related to the use of a drug. Drug-related problems are relatively common in hospitalised patients and can result in patient morbidity and mortality, and increased costs. In order to get an overview of studies on drug-related problems in hospitalised patients, with specific attention to the incidence of drug-related problems and their costs, to the possibilities of prevention and to the effect of these interventions, we performed a literature search. Incidences of medication errors reported in studies vary widely. The range of reported incidences of adverse drug reactions is even wider. These wide ranges can be largely explained by the different study methods and definitions used. Problems related to drug therapy may be averted by preventive interventions. Several possibilities for prevention exist, especially for the prevention of medication errors. Prescribing, transcription and interpretation errors can be reduced by using computerised physician order entry. Together with the use of automated dispensing systems and bar-code technology, this will aid in the reduction of both dispensing and administration errors. Education of nursing staff involved in the process of drug distribution is another important measure for preventing medication errors. Finally, the introduction of systems for the early detection of adverse drug reactions may help to reduce problems related to drug therapy. Identifying risk factors that contribute to the development of adverse drug reactions, may aid in the prevention of these reactions.