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Drug-related deaths by region, sex, and age group per 100 injecting drug users in Scotland, 2000-01.

BACKGROUND: In 2000 and 2001, there were 292 and 332 drug-related deaths in Scotland, respectively. Of the 332 people who died in 2001, 65 were of female sex, 80 were younger than 25 years, and 112 were older than 34 years. We assessed the effect of region, sex, and age group on drug-related deaths in Scotland per 100 injecting drug users. METHODS: We used published regional estimates of current injecting drug users (n=22805), their sex (30% female) and age distribution (8% older than 34 years in mid-1990s), or corresponding data for problem drug users (21% older than 34 years in 2000) to compare observed with expected drug-related deaths by region, sex, and age group per 1000 population or per 100 injecting drug users. FINDINGS: Regional population-based expectations fitted poorly to observed drug-related deaths, but those based on injecting drug users fitted tolerably. Drug-related deaths in 2001 per 100 injecting drug users were significantly lower in female (0.9 [95% CI 0.6-1.1]) than in male drug users (1.5; 1.3-1.7). They were between two and six times more frequent per 100 injecting drug users older than 34 years than younger than 25 years, depending on whether current injecting drug users' age distribution was assumed to be the same as problem drug users' or as injecting drug users' in the mid-1990s (2.1 [1.7-2.5] or 5.3 [4.3-6.3], respectively). INTERPRETATION: Older and male injecting drug users were at highest risk of drug-related death. Injecting drug users' age distribution should be assessed and compared across countries.

Adolescent↗

An 8-year study of multiple influences on drug use and drug use consequences.

Multiple long-term influences on young adult drug use and abuse were tested within an interactionist perspective using latent-variable causal models. Intrapersonal influences included early drug use and social conformity. Proximal interpersonal influences were captured by perceived peer drug use, perceived adult drug use, and family disruption. More distal influences included perceptions of community approval or disapproval for drug use. Outcome measures included not only use of drugs but also disruptive drug use (getting high at work or school) and self-admitted problems with drugs. Data were obtained from 654 participants at three equally spaced time points during an 8-year longitudinal study that began when the subjects were in junior high school. Confirmatory factor analyses were used to test the adequacy of the hypothesized measurement model. Subsequently, a structural equation, or path model, was used to examine the across-time relations among the latent and manifest variables. Stability effects were found for all repeatedly measured latent variables across the 4-year spans. Social conformity strongly influenced other latent variables across time. Early drug use and perceived adult drug use were prominent predictors of young adult drug use, whereas prior drug use predicted disruptive drug use and a lack of social conformity predicted problems with drug use. Early adult alcohol use predicted later disruptive drug use and problems with drug use. Perceived adult drug use generally influenced later alcohol use, whereas peer drug use influenced later cannabis and hard-drug use. Implications for prevention and treatment using a multicausal interactionist perspective are discussed.

Adult↗

Role of drug metabolism in drug discovery and development.

Metabolism by the host organism is one of the most important determinants of the pharmacokinetic profile of a drug. High metabolic lability usually leads to poor bioavailability and high clearance. Formation of active or toxic metabolites will have an impact on the pharmacological and toxicological outcomes. There is also potential for drug-drug interactions with coadministered drugs due to inhibition and/or induction of drug metabolism pathways. Hence, optimization of the metabolic liability and drug-drug interaction potential of the new chemical entities are some of the most important steps during the drug discovery process. The rate and site(s) of metabolism of new chemical entities by drug metabolizing enzymes are amenable to modulation by appropriate structural changes. Similarly, the potential for drug-drug interactions can also be minimized by appropriate structural modifications to the drug candidate. However, the optimization of the metabolic stability and drug-drug interaction potential during drug discovery stage has been largely by empirical methods and by trial and error. Recently, a lot of effort has been applied to develop predictive methods to aid the optimization process during drug discovery and development. This article reviews the role of drug metabolism in drug discovery and development.

Animals↗

Lymphocyte reactivity to ex-vivo drug antigens in drug-induced hepatitis.

The diagnosis of drug-induced hepatitis is usually based on clinical criteria, with emphasis on both the temporal relationship between drug intake and liver injury and the exclusion of alternative causes. In vitro tests of lymphocyte sensitization to drugs are considered to have a low sensitivity. We investigated the possibility of detecting lymphocyte reactivity to drugs in drug-induced hepatitis by analyzing the lymphocyte proliferative responses to ex-vivo drug or metabolite antigens to improve the sensitivity of the in vitro test. Lymphocyte proliferative responses to five different concentrations of the drug and to ex-vivo drug antigens (serum collected from normal subjects after the ingestion of the drugs) were analyzed in 25 patients with a clinical diagnosis of drug-induced hepatitis, 27 healthy subjects and 10 individuals with a recent exposure to the same drugs without development of adverse drug reactions. In seven of the 25 patients, lymphocyte reactivity to drugs was detected (28%). The use of sera collected from healthy volunteers after drug intake (ex-vivo drug antigens) and the addition of a prostaglandin inhibitor to the cultures allowed the detection of lymphocyte sensitization in seven additional cases, increasing the detection ability from 28% to 56%. We suggest that the use of ex-vivo drug antigens may represent a significant contribution to the identification of the drug involved in cases of drug-induced hepatitis.

Adult↗

A calorimetric study on diflunisal release from poly(lactide-co-glycolide) microspheres by monitoring the drug effect on dipalmitoylphosphatidylcholine liposomes: temperature and drug loading influence.

Diflunisal release from poly-Lactide-co-Glycolide (50:50, 34,000 MW) microspheres loaded with two different amounts of drug (2.5 +/- 0.5% and 10 +/- 0.5% w/w) was monitored by following the effects exerted by the drug on the thermotropic behavior of dipalmitoylphosphatidylcholine unilamellar vesicles at different temperatures. The effects of the drug released from the microspheres on the thermotropic behavior of lipid aqueous dispersion containing different molar ratios of drug was detected by differential scanning calorimetry and was compared with the effects exerted by the free Diflunisal. Diflunisal affects mainly the temperature (Tm) of the transition characteristic of phospholipid vesicles as model biomembrane, causing a shift toward lower values. This shift was modulated by the drug molar fraction with respect to the lipid concentration in the aqueous dispersion. Afterward, calorimetric measurements were performed on suspensions of blank liposomes added to weighed amounts of unloaded and differently Diflunisal-loaded microspheres as well as free powdered Diflunisal after incubation for increasing times at three different temperatures (25, 37, and 50 degrees C). The Tm shifts of the lipid bilayer, caused by the drug released from polymeric system as well as by the free drug during incubation periods, were compared with that caused by free drug increasing molar fractions dispersed directly on the membrane, employed as a calibration curve to obtain the fraction of drug released. This in vitro study suggests that the kinetic process involved in drug release is influenced by the amount of drug loaded in the microspheres as well as by the temperature acting on drug solubility and membrane disorder. This drug release model, monitored by the calorimetric technique shows that a) the poly-Lactide-co-Glycolide microspheres are a good delivery system able to sustain the drug release; b) the differential scanning calorimetry technique applied on the drug interaction with biomembranes constitutes a good tool to follow the drug release; 3) this model, representing an innovative alternative in vitro model, should be used to determine the different kinetics involved in the drug transfer from a drug delivery system to a membrane as uptake site.

1,2-Dipalmitoylphosphatidylcholine↗

Assessment of the quality and quantity of drug-drug interaction studies in recent NDA submissions: study design and data analysis issues.

This report investigates the quality and quantity of drug-drug interaction studies in recent new drug applications (NDAs). Eighty-nine studies contained in 14 NDAs submitted between December 1995 and November 1996 to the U.S. Food and Drug Administration (FDA) were reviewed. The results indicated that the median number of clinical drug-drug interaction studies per NDA was 6, almost double that of a 1994-1995 survey. In vitro metabolism data were present in 70% of the submissions. More than 50% of the submissions contained interaction studies using a battery of drugs (cimetidine, digoxin, or warfarin) without optimal use of the in vitro metabolism or in vivo mass balance data. Various study designs using a median number of 12 subjects were employed in the evaluation of drug-drug interactions. Some of the important study design factors such as dose size, dosing regimen, dosing duration, and timing of coadministration were considered, although not consistently, by the sponsors in their study design. Seventy-five percent of the studies used normal, healthy male subjects, and 25% used patients for whom the new molecular entities were intended. In 33% of the studies, female subjects were also recruited. Although the majority (80%) of the submissions still used p-values to determine the significance of drug interactions, 30% used a more relevant equivalence approach with 90% confidence intervals for key pharmacokinetic and/or pharmacodynamic parameter ratios to assess the extent of drug interactions. Overall, 82% of the studies concluded no interaction. Although population pharmacokinetic analysis can be a useful tool in studying drug-drug interactions, only 21% of the submissions used this approach. In summary, this assessment reveals that the quantity and quality of drug-drug interaction studies in NDAs have improved over the years. These improvements, as well as others that can be implemented, should result in more informative labeling and better patient care. FDA guidance for industry dealing with the design, analysis, and labeling language of in vivo metabolic drug-drug interactions has been developed to assist sponsors and FDA reviewers with these issues.

Clinical Trials as Topic↗

Clinical-pharmacological strategies to assess drug interaction potential during drug development.

Drug interactions in patients receiving multiple drug regimens are a constant concern for the clinician. With the increased availability of new drugs and their concomitant use with other drugs, there has been a rise in the potential for adverse drug interactions as demonstrated by the recent withdrawals of newly marketed drugs because of unacceptable interaction profiles. Therefore, the interaction potential of a new compound has to be assessed in detail, starting with preclinical in vitro and in vivo studies at candidate selection and continuously followed up through preclinical and clinical development. Since formal in vivo studies of all possible drug interactions are neither practicable nor suggestive, a careful selection of a limited number of drug combinations to be investigated in vivo during the development phase is indicated. Based on knowledge of pharmacokinetic and biopharmaceutical properties, a well balanced link between in vitro investigations and carefully selected in vivo interaction studies allows full assessment of the potential of a new drug to cause clinically relevant pharmacokinetic drug-drug interactions, prediction of a lack of interactions and derivation of the proper dose recommendations. Clinical pharmacology plays a number of key roles within the process of collecting information on drug interactions during preclinical and clinical development: addressing issues and/or favourable properties to be expected, thus contributing to the scientific assessment of development potential; setting up a rational in vivo drug-drug interaction programme; performing early mechanistic studies to link in vitro with in vivo information (employing 'cocktail' approaches if possible); reviewing co-medication sections for clinical trials; and conducting labelling-oriented interaction studies, after proof of concept. The fact that interactions can occur between various active substances should by itself be a conclusive argument against unnecessary polypharmacy. Prescribing fewer drugs on a rational basis can reduce the risk of adverse effects secondary to drug interactions and may help to improve the quality of drug treatment and to save costs.

Drug Approval↗

Models for assessing the relationship between drug concentration and drug effect in performance horses.

The actions of most drugs are dependent upon achieving adequate plasma concentrations. Plasma concentrations are influenced by the degree to which a drug is absorbed, distributed, metabolized and excreted. Pharmacokinetic assessment reflects changes in these variables as a function of time. Pharmacodynamics refers to specific drug effects or mechanisms of drug action. Individual drug pharmacokinetics provides information on which to base a therapeutic dose, route of administration and dosing interval. However, not all drug actions temporally correlate with plasma kinetics. To resolve this discrepancy, pharmacodynamic models of drug action have been developed. In this review several pharmacodynamic models of anti-inflammatory and central nervous system effects are discussed in relationship to individual drug pharmacokinetics in the horse. The use of appropriate statistical models can minimize error and maximize the detection of drug effects over time. Data are presented showing the value of pharmacodynamic models in assessing and predicting the onset, peak and duration of drug action. Penetration of drugs into inflamed tissue or the brain may not temporally correlate with plasma kinetics. Therefore, drug kinetics in tissues or compartments associated with a particular effect may be a better predictor of efficacy than plasma concentrations. Recent studies have shown that exercise can affect drug disposition and influence both pharmacokinetics and pharmacodynamics. In competitive athletes, plasma or urine concentrations of drugs are determined to regulate use. Some jurisdictions are advocating the establishment of specific drug thresholds based upon plasma or urine concentrations. However, drug effects may occur during low or undetectable plasma concentrations. Urine concentrations are often dissociated in time from those in plasma. Therefore, the use of appropriate pharmacodynamic models, and the exercising horse, can complement plasma pharmacokinetics in determining drug efficacy and drug thresholds.

Animals↗

Drug utilization pattern of antiepileptic drugs and traditional Chinese medicines in a general hospital in Taiwan - a pharmaco-epidemiologic study.

OBJECTIVE: Studies on antiepileptic drug utilization are important for the optimization of drug therapy and drug control. The present study was to evaluate the drug utilization pattern of standard antiepileptic drugs and traditional Chinese medicines (TCMs) in the treatment of different types of epilepsy in a general hospital in Taiwan. METHOD: The epileptic patients under antiepileptic drug treatment at Veterans General Hospital-Taipei were considered in the analysis. Current diagnosis was obtained by the neurologist in charge of the patient. All patients were interviewed by standard questionnaire designed to provide specific information on the types of antiepileptic drugs and details of their use. The questionnaire also sought to determine whether TCMs were used, and whether patients were using TCMs in combination with hospital standard treatment. The results were analysed by descriptive statistics. RESULTS: 729 patients with epilepsy definitely diagnosed were analysed in the study. 445 patients (61.04%) were prescribed with one antiepileptic drug. Combinations of two antiepileptic drugs were prescribed to 261 patients (35.80%), and combinations of three or more antiepileptic drugs to 23 patients (3.16%). A total of 1039 antiepileptic drugs was prescribed, corresponding to an average 1.42 drugs per patient. The most frequently prescribed antiepileptic drug was carbamazepine (56.93%), followed by phenytoin (31.96%), valproate (30.73%) and clonazepam (14.13%). Among the 729 epileptic patients, 83.68% used standard antiepileptic drugs alone, 16.32% used antiepileptic drugs in combination with TCMs. CONCLUSION: Monotherapy is the type of therapy most frequently used in all types of seizures. The selection of antiepileptic drugs is based on efficacy for specific seizure types and epileptic syndromes. The most frequently prescribed antiepileptic drug was carbamazepine, followed by phenytoin, valproate and clonazepam. As some of the patients used TCMs for treatment of epilepsy even when scientific medicine has been provided, further studies on the possible interactions between TCMs and antiepileptic drugs are in progress.

Adult↗

Polypharmacy and possible drug-drug interactions among diabetic patients receiving home health care services.

OBJECTIVES: In this study, we examined the drug regimens of diabetic patients receiving home health care services to measure the prevalence of polypharmacy and to assess the likelihood of drug-drug interactions, a consequence of polypharmacy. DESIGN: The sample consisted of 139 diabetic patients who received home health care services from one home health agency in a large mid-Atlantic city. The data were collected from March 1, 1998 to September 30, 1999. Information regarding medications was collected by the home health nurse during the initial home visit and was recorded on the medication sheet in the patient's clinical record. Any changes in medications were noted on the medication sheets. METHODS: We identified all systemic medications prescribed for 139 home health patients. To assess drug-drug interactions, we used Micromedex formulary DRUG-REAX System. OUTCOMES: We calculated (1) the number of systemic medications taken, and (2) the number of possible severe, moderate, and mild drug-drug interactions. RESULTS: We found that the average number of medications taken was 8.9 (SD 3.4) prescribed medications per day. Our results show that 38.8% of the patients in the sample could potentially be subject to at least one severe drug-drug interaction. Nearly all of the patients (92.8%) were at risk for moderate drug-drug interactions, and 70.5% could have mild drug- drug interactions. CONCLUSION: We conclude that polypharmacy is a concern for home health care patients with diabetes and the potential for drug-drug interactions is substantial. Our results indicate that the drug regimens of diabetic patients should be monitored systematically to avoid adverse events such as hospitalization. Family practitioners and home health care takers are in a unique position to identify polypharmacy and to modify drug regimens.

Aged↗

Does random urine drug testing reduce illicit drug use in chronic pain patients receiving opioids?

BACKGROUND: Prescription drug abuse and illicit drug use are common in chronic pain patients. Adherence monitoring with screening tests, and urine drug testing, periodic monitoring with prescription monitoring programs, has become a common practice in recent years. Random drug testing for appropriate use of opioids and use of illicit drugs is often used in pain management practices. Thus, it is expected that random urine drug testing will deter use of illicit drugs, and also improve compliance. OBJECTIVES: To study the prevalence of illicit drug use in patients receiving opioids for chronic pain management and to compare the results of illicit drug use with the results from a previous study. DESIGN: A prospective, consecutive study. SETTING: Interventional pain management practice setting in the United States. METHODS: A total of 500 consecutive patients on opioids, considered to be receiving stable doses of opioids supplemental to their interventional techniques, were studied by random drug testing. Testing was performed by rapid drug screen. Results were considered positive if one or more of the monitored illicit drugs including cocaine, marijuana (THC), methamphetamine or amphetamines were present. RESULTS: Illicit drug use was evident in 80 patients, or 16%, with marijuana in 11%, cocaine in 5%, and methamphetamine and/or amphetamines in 2%. When compared with previous data, the overall illicit drug use was significantly less. Illicit drug use in elderly patients was absent. CONCLUSION: The prevalence of illicit drug abuse in patients with chronic pain receiving opioids continues to be a common occurence. This study showed significant reductions in overall illicit drug use with adherence monitoring combined with random urine drug testing.

Adult↗

Developing drug-use profiles from drug-charge records.

The potential for developing a drug-use profile from drug-charge records was studied at an 830-bed community hospital. Patient drug charges were reviewed retrospectively for one year (1975) to identify: (1) which key drugs accounted for a high percentage of cost and usage; (2) where key drugs were used within the hospital; (3) how they were used; and (4) who were the chief prescribers. Of the drugs used, 8% accounted for 80% of total drug product costs. Seven drug groups (10% of the total drug groups) appeared in the top 10 of both drug cost and quantity categories. Six individual drugs also appeared in the top 10 of both categories. According to cost, cephalosporin antibiotics were ranked first among drug groups but were sixth according to quantity. Analgesics-antipyretics were ranked first among drug groups by quantity and second by cost. Cephalothin was ranked first among individual drugs by cost and was not in the top 10 in quantity. Diazepam was ranked first among individual drugs by quantity and third by cost. Patients' drug-charge records can be used effectively to generate drug-use profiles for ongoing drug use review, quality assurance and cost containment programs.

California↗

History of drug exposure as a determinant of drug self-administration.

Drug self-administration is controlled, in part, by the subject's history of drug exposure. Although a history of drug administration is not necessary for many drugs to function as reinforcers, prior exposure can increase the likelihood that certain drugs, such as ethanol, will maintain behavior. While it has been demonstrated that physiological dependence is not necessary for a drug to function as a reinforcer, the conditions under which such dependence is maintained can control the later self-administration of the drug. Once drug-maintained behaviors are established, the particular drug that maintains behavior can influence the initial pattern of intake of a new drug and thus the dose of that drug that will maintain behavior. Additionally, under certain conditions, similarity between the discriminative stimulus effects of the drug that previously maintained behavior and those of a new drug can increase the likelihood that the new drug will function as a reinforcer. Finally, stimuli that have been paired with drug administration can powerfully control later drug-maintained behavior, the direction of such control being determined by the conditions under which such pairing occurred. In summary, both the type of drug with which a subject has experience as well as the contingencies governing that experience contribute to subsequent drug self-administration.

Animals↗

Expression of multidrug resistance-associated protein in NIH/3T3 cells confers multidrug resistance associated with increased drug efflux and altered intracellular drug distribution.

Multidrug resistance is a major obstacle to cancer treatment. Using an expression cDNA library transfer approach to elucidating the molecular basis of non-P-glycoprotein-mediated multidrug resistance, we previously established that expression of multidrug resistance protein (MRP), an ATP-binding cassette superfamily transporter, confers multidrug resistance (G. D. Kruh et al., Cancer Res., 54: 1649-1652, 1994). In the present study, we generated NIH/3T3 MRP transfectants without using chemotherapeutic drugs to facilitate the pharmacological analysis of the MRP phenotype. MRP transfectants displayed increased resistance to several lipophilic drugs, including doxorubicin, daunorubicin, etoposide, actinomycin D, vincristine, and vinblastine. However, increased resistance was not observed for Taxol, a drug for which transfection of MDR1 confers high levels of resistance. Verapamil increased the sensitivity of MRP transfectants relative to control transfectants, but reversal was incomplete for doxorubicin and etoposide, the drugs for which MRP conferred the highest resistance levels. For the latter two drugs, MRP transfectants, which were approximately 8- and approximately 10-fold more sensitive than control cells in the absence of verapamil, exhibited 3.8- and 3.3-fold relative sensitization with 10 microM verapamil, respectively, but remained approximately 2 and approximately 3-fold more resistant than control cells. Analysis of drug kinetics using radiolabeled daunorubicin revealed decreased accumulation and increased efflux in MRP transfectants. Confocal microscopic analysis of intracellular daunorubicin in MRP transfectants was consistent with reduced intracellular drug concentrations, and also revealed an altered pattern of intracellular drug distribution characterized by the initial accumulation of drug in a perinuclear location, followed by the development of a punctate pattern of drug scattered throughout the cytoplasm. This pattern was suggestive of a process of drug sequestration, possibly followed by vesicle transport. Both increased drug efflux and perinuclear drug accumulation are consistent with the reported localization of MRP in plasma and cytosolic membranes (N. Krishnamachary and M. S. Center, Cancer Res., 53: 3658-3663, 1993; M. J. Flens et al., Cancer Res., 54: 4557-4563, 1994). These results thus indicate that the drug specificity of MRP is quite similar to that of MDR1, but also suggest potential differences in Taxol specificity and the level of verapamil sensitivity. In addition, these results indicate that MRP functions to extrude drug from the cell, but additionally suggest the intriguing possibility that drug sequestration contributes to drug resistance by protecting cellular targets and/or contributing to drug efflux.

3T3 Cells↗

Fatal adverse drug events: the paradox of drug treatment.

OBJECTIVE: Study patient characteristics, morbidity patterns and drug regimens associated with fatal adverse drug events (FADEs) amongst medical department inpatients. DESIGN: An observational, descriptive study using aggregated medical records, autopsies and pre and postmortem drug analyses. SETTING: A department of internal medicine at a Norwegian county hospital. SUBJECTS: All patients dying in the department over a 2-year period. RESULTS: The incidence of FADEs were 18.2% (133/732). Compared with non-FADE cases, FADE cases were older, used more drugs both on admission and at death, and had higher comorbidity (P < 0.001). Drugs suspected to cause or contribute to fatal outcome were mainly those used for treating chronic pulmonary diseases (terbutaline, theophylline), antithrombotic drugs (aspirin, warfarin, heparines) and drugs for treating coronary heart disease and heart failure (e.g. diuretics, nitrates, angiotensin converting enzymes (ACE) inhibitors, calcium channel blockers). Bronchodilatory drugs, antithrombotic drugs and cardiovascular drugs account for 26, 31 and 30 FADE cases, respectively. Patients dying from gastrointestinal diseases had the highest relative FADE occurrence (42%), cancer patients the lowest occurrence (4%). Serious drug-drug and drug-disease interactions were frequently suspected. Various degrees of inappropriateness in choice of drug, dosage or administration route were seen in 50% of FADE cases. CONCLUSIONS: This study shows a high incidence of FADEs associated with high age, high comorbidity and polypharmacy, and partly to inappropriate drug prescribing or use. Treatments frequently associated with FADEs were bronchodilatory treatment of patients with both chronic obstructive lung disease and coronary heart disease, vasodilatory treatment in patient with endstage heart failure and the combination of several antithrombotic drugs. A systematic strategy is needed to avoid unnecessary adverse drug events (ADEs).

Adult↗

Prevalence of potentially severe drug-drug interactions in ambulatory patients with dyslipidaemia receiving HMG-CoA reductase inhibitor therapy.

BACKGROUND: Drug-drug interactions (DDIs) are a well known risk factor for adverse drug reactions. HMG-CoA reductase inhibitors ('statins') are a cornerstone in the treatment of dyslipidaemia and patients with dyslipidaemia are concomitantly treated with a variety of additional drugs. Since DDIs are associated with adverse reactions, we performed a cross-sectional study to assess the prevalence of potentially critical drug-drug and drug-statin interactions in an outpatient adult population with dyslipidaemia. METHODS: Data from patients with dyslipidaemia treated with a statin were collected from 242 practitioners from different parts of Switzerland. The medication list was screened for potentially harmful DDIs with statins or other drugs using an interactive electronic drug interaction program. RESULTS: We included 2742 ambulatory statin-treated patients (mean age +/- SD 65.1 +/- 11.1 years; 61.6% males) with (mean +/- SD) 3.2 +/- 1.6 diagnoses and 4.9 +/- 2.4 drugs prescribed. Of those, 190 patients (6.9%) had a total of 198 potentially harmful drug-statin interactions. Interacting drugs were fibrates or nicotinic acid (9.5% of patients with drug-statin interactions), cytochrome P450 (CYP) 3A4 inhibitors (70.5%), digoxin (22.6%) or ciclosporin (cyclosporine) [1.6%]. The proportion of patients with a potential drug-statin interaction was 12.1% for simvastatin, 10.0% for atorvastatin, 3.8% for fluvastatin and 0.3% for pravastatin. Additionally, the program identified 393 potentially critical non-statin DDIs in 288 patients. CONCLUSIONS: CYP3A4 inhibitors are the most frequent cause of potential drug interactions with statins. As the risk for developing rhabdomyolysis is increased in patients with drug-statin interactions, clinicians should be aware of the most frequently observed drug-statin interactions and how these interactions can be avoided.

Aged↗

Renal failure, drug pharmacokinetics and drug action.

Patients with renal insufficiency often react abnormally to a number of drugs. Small doses that are safe under normal conditions may cause severe and even fatal side-effects. As a consequence, modification of the usual drug dosage of these drugs in required in renal insufficiency. Since the risk of retention concerns only those drugs which are mainly excreted by the kidney, it is possible to establish a mathematical relationship between glomerular filtration rate and the rate of drug elimination. These relationships serve as a basis for the determination of the proper dosage regimen for the individual patient. Such dosage adaptation for intermitten drug administration can be obtained by two methods and a series of compromises between them: (1) increase of the dosage interval without changing the dose, and (2) reduction of the does without changing the frequency of administration. One must however, not only consider inadequate drug elimination but also a number of other factors. Some of these modify the behaviour of the drug, such as hypoalbumineamia, which causes an increase of the unbound portion of the drug; anomalies of the volume of distribution, as found in patients with oedema; metabolic disturbance; alteration of absorption from the gastro-intestinal tract, etc. Other factors are related only indirectly to the pharmacokinetic behaviour of the drug. Frequently, there is an increased sensitivity to the undesirable side-effects of certain drugs in patients with renal insufficiency, causing the level of tolerance to be lowered compared with normal patients. Such an effect probably involves functional or morphological modifications of the drug receptors, or interaction with substance retained in renal insufficiency. Furthermore, drugs may accentuate the consequences of the nephropathy or have increased nephrotoxicity for those with diseased kidneys. It is with these important reservations that a critical analysis of the proposed methods of adapting drug dosage in renal insufficiency is presented. An appendix tabulates the effects of renal insufficiency on the behaviour of 117 drugs. Irrespective of the method used to calculate drug dosage, all patients with renal disease must be monitored closely, particularly for signs of unexpected drug toxicity.

Drug Administration Schedule↗

Are novel drugs more risky for patients than less novel drugs?

The Food and Drug Administration has accelerated the approval of therapeutically novel drugs so that patients have faster access to innovative drug therapies. Little research, however, has examined the variation in risks among therapeutically novel and less novel drugs. Do drugs that represent greater novelty also entail greater risks for patients? This paper uses post-marketing drug safety surveillance data from the FDA to examine the adverse drug reactions (ADRs) associated with novel and less novel drugs. Negative binomial regressions are used to examine the impact of a drug's FDA novelty rating on its ADR count controlling for differences in drug utilization, the conditions being treated, disease characteristics, patient characteristics, drug review times, and year-specific effects. Results show that drugs deemed novel by the FDA are associated with a greater number of serious drug reactions, including those that result in hospitalization and death, than less novel drugs. These results suggest that novel drugs pose greater risk of serious ADRs for patients relative to less novel drugs.

Adverse Drug Reaction Reporting Systems↗