Lack of therapeutic interchangeability of HMG-CoA reductase inhibitors

Formulation and In Vitro Evaluation of Self Microemulsifying Drug Delivery System Containing Atorvastatin Calcium

OBJECTIVE

The aim of this study was to develop a new dosage form as an alternative to the classical tablet forms of atorvastatin calcium (AtrCa). The formulation strategy was to prepare an optimum self micro emulsifying drug delivery system (SMEDDS) to overcome the problem of low solubility of the active substance.

METHODS

In this study, pseudo ternary phase diagrams were plotted determined by the solubility studies. According to the solubility studies; oleic acid was used as the oil phase, Tween 20 and Span 80 were used as the surfactants and ethanol was used as the co-surfactant. SMEDDS formulations were characterized according to pH, electrical conductivity, density, refractive index, viscosity, emulsification time, dispersibility, robustness of dilution stability, droplet size, polidispersity index, zeta potential, transmittance %, cloud point, content quantification %, chemical and physical stability. The lipolysis study was conducted under fed and fasted conditions. In vitro release studies and kinetic evaluation were carried out. Permeability studies were also examined with Caco-2 cell culture.

RESULTS

The droplet size of the optimized formulation did not change significantly in different medias over the test time period. Improved SMEDDS formulation will progress steadily without precipitating along the gastrointestinal tract. Lipolysis studies showed that the oil solution had been exposed to high amount of lipolysis compared to the SMEDDS formulation. The release rate of AtrCa from AtrCa- SMEDDS formulation (93.8%, at 15 minutes) was found as increased when the results were compared with commercial tablet formulation and pure drug. The permeability value of AtrCa from AtrCa- SMEDDS formulation was found higher than pure AtrCa and commercial tablet formulation, approximately 9.94 and 1.64 times, respectively.

CONCLUSION

Thus, lipid-based SMEDDS formulation is a potential formulation candidate for lymphatic route in terms of the increased solubility of AtrCa.

Finding the Balance Between Benefits and Harms When Using Statins for Primary Prevention of Cardiovascular Disease: A Modeling Study

BACKGROUND

Many guidelines use expected risk for cardiovascular disease (CVD) during the next 10 years as a basis for recommendations on use of statins for primary prevention of CVD. However, how harms were considered and weighed against benefits is often unclear.

OBJECTIVE

To identify the expected risk above which statins provide net benefit.

DESIGN

Quantitative benefit-harm balance modeling study.

DATA SOURCES

Network meta-analysis of primary prevention trials, a preference survey, and selected observational studies.

TARGET POPULATION

Persons aged 40 to 75 years with no history of CVD.

TIME HORIZON

10 years.

PERSPECTIVE

Clinicians and guideline developers.

INTERVENTION

Low- or moderate-dose statin versus no statin.

OUTCOME MEASURES

The 10-year risk for CVD at which statins provide at least a 60% probability of net benefit, with baseline risk, frequencies of and preferences for statin benefits and harms, and competing risk for non-CVD death taken into account.

RESULTS OF BASE-CASE ANALYSIS

Younger men had net benefit at a lower 10-year risk for CVD than older men (14% for ages 40 to 44 years vs. 21% for ages 70 to 75 years). In women, the risk required for net benefit was higher (17% for ages 40 to 44 years vs. 22% for ages 70 to 75 years). Atorvastatin and rosuvastatin provided net benefit at lower 10-year risks than simvastatin and pravastatin.

RESULTS OF SENSITIVITY ANALYSIS

Most alternative assumptions led to similar findings.

LIMITATION

Age-specific data for some harms were not available.

CONCLUSION

Statins provide net benefits at higher 10-year risks for CVD than are reflected in most current guidelines. In addition, the level of risk at which net benefit occurs varies considerably by age, sex, and statin type.

PRIMARY FUNDING SOURCE

Swiss Government Excellence Scholarship Office, Béatrice Ederer-Weber Foundation, and North-South Cooperation at the University of Zurich.

Effect of therapeutic interchange on medication reconciliation during hospitalization and upon discharge in a geriatric population

Background

Therapeutic interchange of a same class medication for an outpatient medication is a widespread practice during hospitalization in response to limited hospital formularies. However, therapeutic interchange may increase risk of medication errors. The objective was to characterize the prevalence and safety of therapeutic interchange.

Methods and findings

Secondary analysis of a transitions of care study. We included patients over age 64 admitted to a tertiary care hospital between 2009–2010 with heart failure, pneumonia, or acute coronary syndrome who were taking a medication in any of six commonly-interchanged classes on admission: proton pump inhibitors (PPIs), histamine H₂-receptor antagonists (H2 blockers), hydroxymethylglutaryl CoA reductase inhibitors (statins), angiotensin-converting enzyme (ACE) inhibitors, angiotensin receptor blockers (ARBs), and inhaled corticosteroids (ICS). There was limited electronic medication reconciliation support available. Main measures were presence and accuracy of therapeutic interchange during hospitalization, and rate of medication reconciliation errors on discharge. We examined charts of 303 patients taking 555 medications at time of admission in the six medication classes of interest. A total of 244 (44.0%) of medications were therapeutically interchanged to an approved formulary drug at admission, affecting 64% of the study patients. Among the therapeutically interchanged drugs, we identified 78 (32.0%) suspected medication conversion errors. The discharge medication reconciliation error rate was 11.5% among the 244 therapeutically interchanged medications, compared with 4.2% among the 311 unchanged medications (relative risk [RR] 2.75, 95% confidence interval [CI] 1.45–5.19).

Conclusions

Therapeutic interchange was prevalent among hospitalized patients in this study and elevates the risk for potential medication errors during and after hospitalization. Improved electronic systems for managing therapeutic interchange and medication reconciliation may be valuable.

National Assessment of Statin Therapy in Patients Hospitalized with Acute Myocardial Infarction: Insight from China PEACE-Retrospective AMI Study, 2001, 2006, 2011

Background

Statin therapy is among the most effective treatments to improve short- and long-term mortality after acute myocardial infarction. The use of statin, and the intensity of their use, has not been described in acute myocardial infarction patients in China, a country with a rapidly growing burden of cardiovascular disease.

Methods and Results

Using a nationally representative sample of patients with acute myocardial infarction admitted to 162 Chinese hospitals in 2001, 2006 and 2011, we identified 14,958 patients eligible for statin therapy to determine rates of statin use and the intensity of statin therapy, defined as those statin regimens with expected low-density lipoprotein cholesterol lowering of at least 40%, to identify factors associated with the use of statin therapy. Statin use among hospitalized patients with acute myocardial infarction increased from 27.9% in 2001 to 72.5% in 2006, and 88.8% in 2011 (P<0.001 for trend). Regional variation in statin use correspondingly decreased over time. Among treated patients, those receiving intensive statin therapy increased from 1.0% in 2001 to 24.2% in 2006 to 57.2% in 2011(P<0.001 for trend). Patients without low-density lipoprotein cholesterol measured were less likely to be treated with statin or to receive intensive therapy.

Conclusions

The use of statin therapy has dramatically increased over the past decade in Chinese patients with acute myocardial infarction. However, half of patients still did not receive intensive statin therapy in 2011.Given that guidelines strongly endorse intensive statin therapy for acute myocardial infarction patients, initiatives promoting the use of statin therapy, with attention to treatment intensity, would support further improvements in practice.

Are there any benefits from statin treatment for the septic patient?

Statins have become the most widely used drugs for lowering cholesterol levels worldwide. At least 20% of patients requiring admission to hospital are on established statin therapy, and this proportion is growing each year. Evidence from observational studies and basic science research suggests that statins might be associated with a reduced mortality in sepsis. Randomized trials are producing equivocal results but have not shown the marked improvement in outcome suggested by the observational studies. Continued use in current statin users appears a more fruitful area for future research than statin use de novo as an adjuvant therapy in sepsis. Statin use in patients with pneumonia, acute lung injury or early sepsis warrants further study. International practice of statin use in critically ill patients is variable, and potential toxicity mandates careful monitoring. Further studies are required to address fundamental issues such as efficacy, potential target patient populations, dose, class equivalence and safety.

Changes in low-density lipoprotein cholesterol levels after discharge for acute myocardial infarction in a real-world patient population

Aggressively managing low-density lipoprotein cholesterol (LDL-C) after myocardial infarction (MI) is a cornerstone of secondary prevention. The changes in LDL-C after MI and the factors associated with LDL-C levels are unknown. Therefore, we directly measured fasting LDL-C levels in 797 MI patients from 24 US hospitals from 2005 to 2008. Mean LDL-C levels at discharge, 1 month, and 6 months were 95.1, 81.9, and 87.1 mg/dL, respectively. In a hierarchical, multivariable, repeated measures model, older age, male sex, and hypertension were associated with lower LDL-C levels, whereas self-reported avoidance of health care because of cost was associated with higher LDL-C. Both the presence and intensity of statin therapy at discharge were strongly associated with LDL-C levels, with adjusted mean 6-month changes of -3.4 mg/dL (95% confidence interval (CI): -12.1, 5.3) for no statins; 1.7 mg/dL (95% CI: -4.7, 8.1) for low statins; -10.2 mg/dL (95% CI: -14.5, -6.0) for moderate statins; and -13.9 mg/dL (95% CI: -19.7, -8.0) for intensive statins (P < 0.001). In conclusion, we found that greater reductions in LDL-C levels after MI were strongly associated with the presence and intensity of statin therapy, older age, male sex, hypertension, and better socioeconomic status. These findings support the use of intensive statin therapy in post-MI patients and provide estimates of the expected LDL-C changes after MI in a real-world population.

Patterns and predictors of intensive statin therapy among patients with diabetes mellitus after acute myocardial infarction

Intensive statin therapy is a central component of secondary prevention after acute myocardial infarction (AMI), particularly among high-risk patients, such as those with diabetes mellitus (DM). However, the frequency and predictors of intensive statin therapy use after AMI among patients with DM have not been described. We examined patterns of intensive statin therapy use (defined as a statin with expected low-density lipoprotein cholesterol lowering of >50%) at discharge among patients with AMI with known DM enrolled in a 24-site US registry. Predictors of intensive statin therapy use were evaluated using multivariable hierarchical Poisson regression models. Among 1,300 patients with DM after AMI, 22% were prescribed intensive statin therapy at hospital discharge. In multivariable models, ST-elevation AMI (risk ratio [RR] 1.48, 95% confidence interval [CI] 1.29 to 1.70), insurance for medications (RR 1.28, 95% CI 1.00 to 1.63), and higher low-density lipoprotein cholesterol levels (RR 1.05 per 1 mg/dl, 95% CI 1.02 to 1.07) were independent predictors of intensive statin therapy, whereas higher Global Registry of Acute Coronary Events scores were associated with lower rates of intensive statin therapy (RR 0.94 per 10 points, 95% CI 0.91 to 0.98). In conclusion, only 1 in 5 patients with DM was prescribed intensive statin therapy at discharge after an AMI. Predictors of intensive statin therapy use suggest important opportunities to improve quality of care in this patient population.

Patterns of statin initiation, intensification, and maximization among patients hospitalized with an acute myocardial infarction

BACKGROUND

Intensive statins are superior to moderate statins in reducing morbidity and mortality after an acute myocardial infarction. Although studies have documented rates of statin prescription as a quality performance measure, variations in hospitals' rates of initiating, intensifying, and maximizing statin therapy after acute myocardial infarction are unknown.

METHODS AND RESULTS

We assessed statin use at admission and discharge among 4340 acute myocardial infarction patients from 24 US hospitals (2005-2008). Hierarchical models estimated site variation in statin initiation in naïve patients, intensification in those undergoing submaximal therapy, and discharge on maximal therapy (defined as a statin with expected low-density lipoprotein cholesterol lowering ≥ 50%) after adjustment for patient factors, including low-density lipoprotein cholesterol level. Site variation was explored with a median rate ratio, which estimates the relative difference in risk ratios of 2 hypothetically identical patients at 2 different hospitals. Among statin-naïve patients, 87% without a contraindication were prescribed a statin, with no variability across sites (median rate ratio, 1.02). Among patients who arrived on submaximal statins, 26% had their statin therapy intensified, with modest site variability (median rate ratio, 1.47). Among all patients without a contraindication, 23% were discharged on maximal statin therapy, with substantial hospital variability (median rate ratio, 2.79).

CONCLUSIONS

In a large, multicenter acute myocardial infarction cohort, statin therapy was begun in nearly 90% of patients during hospitalization, with no variability across sites; however, rates of statin intensification and maximization were low and varied substantially across hospitals. Given that more intense statin therapy is associated with better outcomes, changing the existing performance measures to include the intensity of statin therapy may improve care.

Impact of the JUPITER trial on statin prescribing for primary prevention

STUDY OBJECTIVE

As the Justification for the Use of Statins in Prevention: an Intervention Trial Evaluating Rosuvastatin (JUPITER) trial identified a new population of individuals with cholesterol levels below traditional treatment thresholds but with elevated high-sensitivity C-reactive protein (hs-CRP) levels who may benefit from primary prevention with statin therapy, we sought to evaluate the impact of this trial on the incident prescription rates of rosuvastatin alone as well as all statins in a primary prevention population.

DESIGN

Population-based, cross-sectional time-series analysis.

DATA SOURCE

Administrative health care databases in Ontario, Canada.

PATIENTS

A total of 299,809 incident statin users 66 years or older were identified during the study period, from January 1, 2003, to March 31, 2011, who were prescribed statin therapy for primary prevention.

MEASUREMENTS AND MAIN RESULTS

We evaluated the incident rate of rosuvastatin and all statin use during each quarter of the study period. Overall, no significant trends in all incident statin use were observed (p=0.99). Furthermore, no significant differences were observed in incident rates of rosuvastatin (p=0.21) or all statin (p=0.41) use after the publication of the JUPITER trial. Despite the lack of impact of the JUPITER trial on rosuvastatin or all statin utilization, the relative market share of rosuvastatin increased from 9% to 65% over the study period.

CONCLUSION

The publication of the JUPITER trial did not significantly affect trends in overall statin and rosuvastatin prescribing patterns for primary prevention in this study. Increases in the relative market share of rosuvastatin may be attributed to the impact of the pharmaceutical industry on prescribing patterns. Our results highlight the need to further improve the integration of evidence-based prescribing into cost-effective clinical practice.

Comparison of the efficacies of five different statins on inhibition of human saphenous vein smooth muscle cell proliferation and invasion

Statins (HMG-CoA reductase inhibitors) exhibit beneficial effects on the vasculature independently of their cholesterol-lowering properties. These pleiotropic effects underlie the ability of statins to reduce intimal hyperplasia in saphenous vein (SV) bypass grafts by attenuating smooth muscle cell (SMC) invasion and proliferation. Although all statins can effectively lower cholesterol, the pleiotropic effects of individual statins may well differ. We therefore compared the concentration-dependent effects of 4 lipophilic statins (simvastatin, atorvastatin, fluvastatin, and lovastatin) and 1 hydrophilic statin (pravastatin) on the proliferation and invasion of SMC cultured from SV of 9 different patients undergoing coronary artery bypass grafting (CABG). The lipophilic statins inhibited SV-SMC proliferation over a 4-day period with an order of potency of fluvastatin > atorvastatin > simvastatin > lovastatin (IC50 range = 0.07 to 1.77 microM). Similarly, these statins also inhibited SV-SMC invasion through an artificial basement membrane barrier (fluvastatin > atorvastatin > simvastatin >> lovastatin; IC50 range = 0.92 to 26.9 microM). In contrast, the hydrophilic pravastatin had no significant effect on SV-SMC proliferation at concentrations up to 10 microM, nor did it attenuate SV-SMC invasion (up to 30 microM). Our data provide strong evidence that individual statins possess differential pleiotropic effects on SV-SMC function. This may be of clinical relevance in the selection of individual statins for the treatment of CABG patients.

Rosuvastatin in elderly patients

A progressive accumulation of atherosclerotic lesions beginning early in life puts elderly persons at a greater absolute risk of cardiovascular disease and coronary events than other segments of the population. HMG-CoA reductase inhibitor (statin) therapy has been shown to be both efficacious and well tolerated in most elderly patients. Among the statins, rosuvastatin has advantages in treating older patients: at low starting doses it is very efficacious compared with other statins, and thus more likely to enable patients to reach their low-density lipoprotein-cholesterol goals without the need for titration or combination therapy. Lack of clinically significant interactions with most drugs metabolised by cytochrome P450 enzyme 3A4 may also make rosuvastatin safer for patients taking multiple medications. Furthermore, rosuvastatin has shown efficacy in treating patients with many of the co-morbidities common in the elderly, including renal impairment and diabetes mellitus. As yet, however, cardiovascular endpoint data for rosuvastatin are not available.

Rule-based standardised switching of drugs at the interface between primary and tertiary care

INTRODUCTION

Changes in drug treatment are frequently mandatory with hospital admission and discharge because hospital drug formularies are generally restricted to about 3000 drugs as compared to the many times this number - 62,000 in Germany - that are commercially available. Without computerised support, the process involved with switching drugs to a corresponding generic or a therapeutic equivalent is time-consuming and error-prone.

METHODS

We have developed and tested a standardised interchange algorithm for subsequent implementation into a computerised decision support system that switches drugs to the corresponding generic or a therapeutic equivalent if they are not listed on the hospital drug formulary.

RESULTS

The algorithm was retrospectively applied to the medication regimens of 120 patients (774 prescribed drugs containing 886 active ingredients) at their time of admission to surgical wards. Of the prescribed drugs, 52.8% (409/774) were part of the hospital drug formulary, thereby rendering a switch unnecessary. The 365 drugs not listed consisted of 392 active ingredients that were successfully switched to a corresponding generic (84.7%) or a therapeutic equivalent (10.2%). No specific switching procedures were defined for only 2.3% (20/886) of the active ingredients. In these cases, the drugs were either discontinued (4/20) or special drug classes, current diseases or co-medication required manual switching (8/20), or the drugs were continued unchanged and ordered from a wholesaler (8/20).

CONCLUSION

Using a standardised interchange algorithm, pre-admission drug regimens can successfully be switched to drugs on a hospital drug formulary. These findings suggest that a computerised decision support system will likely be useful to support this important practice.

[Drug interchangeability: clinical approach and consumer's point of view]

The rational construction of an essential drug list, considering the patient's need, drug safety, availability and the best cost-benefit ratio, is based on drug safety, efficacy and quality. However, in daily practice, the prescriber's decision is mostly influenced by drug effectiveness, following criteria that increase adherence to the treatment, such as relative drug toxicity, convenience, cost and prescriber's experience. In addition, frequent launching of new molecules for the same therapeutic indication, together with wide publicity targeting prescribers, interferes with the decision-making process. Similarly, the bonuses offered by the industry for over-the-counter drug sales interfere with the consumer's choice. The confrontation between known human biological variability and the knowledge that there is no absolute similarity between drugs of the same therapeutic class, or even generic drugs, has an impact on the prescriber's drug list, which should include the concept of first and second choice drugs. Prescribers' unfamiliarity with these subjects is a determinant factor for irrational drug use: a public health issue. The objective of this study was to introduce to drug prescribers information that can help them building up a rational drug list for their patients, based on the National Health Surveillance Agency (Anvisa) experience of drug regulation.

Targeting enzyme inhibitors in drug discovery

Drugs that function as enzyme inhibitors constitute a significant portion of the orally bioavailable therapeutic agents that are in clinical use today. Likewise, much of drug discovery and development efforts at present are focused on identifying and optimizing drug candidates that act through inhibition of specific enzyme targets. The attractiveness of enzymes as targets for drug discovery stems from the high levels of disease association (target validation) and druggability (target tractability) that typically characterize this class of proteins. In this expert opinion the authors describe the existing practices and future directions in drug discovery enzymology, with emphasis on how a detailed understanding of the catalytic mechanism of specific targets can be used to identify and optimize small-molecule compounds that interact with conformationally distinct forms of the enzyme, thus resulting in high potency, high selectivity inhibitors.

The benefits of statin therapy--what questions remain?

Early hydroxymethylglutaryl-CoA reductase inhibitor (statin) trials provided the first evidence of the benefits of statin therapy in secondary prevention of coronary heart disease (CHD). Outcomes data from more recent trials involving atorvastatin, fluvastatin, lovastatin, pravastatin, and simvastatin, have since expanded the patient population shown to benefit from statin therapy. Current studies are evaluating the benefits of lowering lipid levels with statins to below current goals, as well as examining benefits in special patient populations and evaluating the value of surrogate markers of CHD. Early trials provided a solid foundation of knowledge on the efficacy and safety of statins. Recent and ongoing trials generate new data to resolve remaining questions in the fields of CHD prevention and lipidology.

Statins research unfinished saga: desirability versus feasibility

Drugs in the same class are generally thought to be therapeutically equivalent because of similar mechanisms of action (the so-called "class effect"). However, statins differ in multiple characteristics, including liver and renal metabolism, half-life, effects on several serum lipid components, bioavailability and potency. Some are fungal derivatives, and others are synthetic compounds. The percentage absorption of an oral dose, amount of protein binding, degree of renal excretion, hydrophilicity, and potency on a weight basis is variable. These differences may be even greater in diabetic patients, who may present diabetes-induced abnormalities in P450 isoforms and altered hepatic metabolic pathways. Thus, it is obvious that head-to-head comparisons between different statins are preferable than trial-to-trial comparisons. Such assessments are of utmost importance, especially in cases in which specific populations with a distinct lipid profile and altered metabolic pathways, like diabetics, are studied. It should be specially pinpointed that patients with metabolic syndrome and diabetes constitute also a special population regarding their atherogenic dyslipidemia, which is usually associated with low HDL-cholesterol, hypertriglyceridemia and predominance of small dense LDL-cholesterol. Therefore, these patients may benefit from fibrates or combined statin/fibrate treatment. This policy is not accomplished since in the real world things are more complex. Trials would require very large sample sizes and long-term follow-up to detect significant differences in myocardial infarction or death between two different statins. Moreover, the fact that new compounds are under several phases of research and development represents an additional drawback for performing the trials. Ideally, head-to-head trials regarding clinically important outcomes should be conducted for all drugs. Nonetheless, the desirability of performing such trials, which epitomize modern evidence-based medicine, is frequently superseded by the feasibility dictated by pragmatic and economic circumstances. In the latter case, in absence of solid systematic documentation of comparable health benefits and long-term safety, both researchers and practicing physicians should allude to the weight of scientific endorsement behind the arguments and seek for the possible strengths and weaknesses intrinsic to each specific study. In any case, conclusions based on surrogate endpoints cannot completely substitute head-to-head comparisons regarding patients' outcome.

Simvastatin inhibits MMP‐9 secretion from human saphenous vein smooth muscle cells by inhibiting the RhoA/ROCK pathway and reducing MMP‐9 mRNA levels

Increased matrix metalloproteinase-9 (MMP-9) expression is associated with intimal hyperplasia in saphenous vein (SV) bypass grafts. Recent evidence suggests that HMG-CoA reductase inhibitors (statins) can prevent the progression of vein graft failure. Here we investigated whether statins inhibited MMP-9 secretion from cultured human SV smooth muscle cells (SMC) and examined the underlying mechanisms. SV-SMC from different patients were exposed to phorbol ester (TPA) or PDGF-BB plus interleukin-1alpha (IL-1). MMP-9 secretion and mRNA expression were analyzed using gelatin zymography and RT-PCR, respectively. Specific signal transduction pathways were investigated by immunoblotting and pharmacological inhibition. Simvastatin reduced TPA- and PDGF/IL-1-induced MMP-9 secretion and mRNA levels, effects reversed by geranylgeranyl pyrophosphate and mimicked by inhibiting Rho geranylgeranylation or Rho-kinase (ROCK). MMP-9 secretion induced by PDGF/IL-1 was mediated via the ERK, p38 MAPK, and NFkappaB pathways, whereas that induced by TPA was mediated specifically via the ERK pathway. Simvastatin failed to inhibit activation of these signaling pathways. Moreover, simvastatin did not affect MMP-9 mRNA stability. Together these data suggest that simvastatin reduces MMP-9 secretion from human SV-SMC by inhibiting the RhoA/ROCK pathway and decreasing MMP-9 mRNA levels independently of effects on signaling pathways required for MMP-9 gene expression.

Statins and liver toxicity: a meta-analysis

STUDY OBJECTIVE

To assess the risk of liver function test (LFT) abnormalities with the use of 3-hydroxy-3-methylglutaryl coenzyme A reductase inhibitors (statins) for the treatment of hyperlipidemia.

DESIGN

Meta-analysis of randomized, placebo-controlled trials of statins used for the treatment of hyperlipidemia or for primary or secondary prevention of cardiovascular disease.

SETTING

University research center.

PATIENTS

A total of 49,275 patients from 13 trials.

INTERVENTION

A literature search of published clinical trials was performed in MEDLINE (January 1966-March 2003) and the Cochrane Controlled Trials Registry (first quarter 2003). Studies also were identified from the references of the trials and of published systematic reviews.

MEASUREMENTS AND MAIN RESULTS

For a trial to be included in the meta-analysis, its duration of follow-up had to be at least 48 weeks and the trial had to include at least 400 patients, with at least 200 treated with a statin. Trials conducted in transplant recipients were excluded. The proportion of patients having LFT abnormalities was low in both groups (statins 1.14% vs placebo 1.05%, odds ratio [OR] 1.26, 95% confidence interval [CI] 0.99-1.62, p=0.07). Only fluvastatin was associated with a significant increase in the odds of having LFT abnormalities (fluvastatin 1.13% vs placebo 0.29%, OR 3.54, 95% CI 1.1-11.6, p=0.04) compared with placebo, although this finding was based on only two trials.

CONCLUSIONS

Our results support previous observations that pravastatin, lovastatin, and simvastatin at low-to-moderate doses are not associated with a significant risk of LFT abnormalities. Additional data are required to determine whether other statins have a similar safety profile.

Patients with Alzheimer's disease may be particularly susceptible to adverse effects of statins

In epidemiological, cross-sectional studies, treatment with 3-hydroxy-3-methylglutaryl coenzyme A reductase inhibitors (statins) prevented to a large extent the development of Alzheimer's disease (AD), but the results of randomized, placebo-controlled studies, focused on statin therapy in patients with ischemic heart disease (IHD), are at variance. Nonetheless, data from epidemiological, longitudinal studies in humans as well as studies on transgenic mouse models and cultured neuronal cell lines indicate that cholesterol may contribute to the pathogenesis of AD. Statins have proven therapeutic and preventive effects in IHD and other vascular diseases in man. They generally are well tolerated, but some adverse effects, probably due to antiproliferative and proapoptotic properties of the statins, are matters of concern. AD patients may be extrasusceptible to adverse effects of statins due to preexisting aberrations in signal transduction and energy metabolism in the neurons and a perturbed cholesterol metabolism in the brain. This problem might be addressed in randomized, double-blind studies with statins in AD. The statins differ from each other in several aspects, and they are not considered to be therapeutically interchangeable. It could be fruitful to use both a placebo and two different types of statins, i.e. an essentially hydrophilic statin and a lipophilic statin, in a double-blinded fashion, and to compare the effects on the cognitive decline in AD.

Genetic polymorphisms in cytochrome P450 enzymes: effect on efficacy and tolerability of HMG-CoA reductase inhibitors

Adverse drug reactions are common; they are responsible for a number of debilitating side effects and are a significant cause of death following drug therapy. It is now clear that a significant proportion of these adverse drug reactions, as well as therapeutic failures, are caused by genetic polymorphism, genetically based interindividual differences in drug absorption, disposition, metabolism, or excretion. HMG-CoA reductase inhibitors are generally very well tolerated and easy to administer with good patient acceptance. There are only two uncommon but potentially serious adverse effects related to HMG-CoA reductase inhibitor therapy: hepatotoxicity and myopathy. The occurrence of lethal rhabdomyolysis in patients treated with cerivastatin has prompted concern on the part of physicians and patients regarding the tolerability of HMG-CoA reductase inhibitors. Apart from pravastatin and rosuvastatin, HMG-CoA reductase inhibitors are metabolized by the phase I cytochrome P450 (CYP) superfamily of drug metabolizing enzymes. The best-characterized pharmacogenetic polymorphisms are those within this enzyme family. One of these enzymes, CYP2D6, plays an important role in the metabolism of simvastatin. It has been shown that the cholesterol-lowering effect as well as the efficacy and tolerability of simvastatin is influenced by CYP2D6 genetic polymorphism. Because the different HMG-CoA reductase inhibitors differ, with respect to the degree of metabolism by the different CYP enzymes, genotyping may help to select the appropriate HMG-CoA reductase inhibitor and the optimal dosage during the start of the treatment and will allow for more efficient individual therapy. A detailed knowledge of the genetic basis of individual drug response is potentially of major clinical and economic importance.