Cerivastatin and gemfibrozil-associated rhabdomyolysis

Preincubation Time-Dependent, Long-Lasting Inhibition of Drug Transporters and Impact on the Prediction of Drug-Drug Interactions

Transporter-mediated drug-drug interaction (DDI) is of clinical concern, and the quantitative prediction of DDIs is an indispensable part of drug development. Cell-based inhibition assays, in which a representative probe substrate and a potential inhibitor are coincubated, are routinely performed to assess the inhibitory potential of new molecular entities on drug transporters. However, the inhibitory effect of cyclosporine A (CsA) on organic anion transporting polypeptide (OATP) 1B1 is substantially potentiated with CsA preincubation, and this effect is both long-lasting and dependent on the preincubation time. This phenomenon has also been reported with transporters other than OATP1Bs, but it is considered more prevalent among OATP1Bs and organic cation transporters. Regulatory agencies have also noted this preincubation effect and have recommended that pharmaceutical companies consider inhibitor preincubation when performing in vitro OATP1B1 and OATP1B3 inhibition studies. Although the underlying mechanisms responsible for the preincubation effect are not fully understood, a trans-inhibition mechanism was recently demonstrated for OATP1B1 inhibition by CsA, in which CsA inhibited OATP1B1 not only extracellularly (cis-inhibition) but also intracellularly (trans-inhibition). Furthermore, the trans-inhibition potency of CsA was much greater than that of cis-inhibition, suggesting that trans-inhibition might be a key driver of clinical DDIs of CsA with OATP1B substrate drugs. Although confidence in transporter-mediated DDI prediction is generally considered to be low, the predictability might be further improved by incorporating the trans-inhibition mechanism into static and dynamic models for preincubation-dependent inhibitors of OATP1Bs and perhaps other transporters. SIGNIFICANCE STATEMENT: Preincubation time-dependent, long-lasting inhibition has been observed for OATP1B1 and other solute carrier transporters in vitro. Recently, a trans-inhibition mechanism for the preincubation effect of CsA on OATP1B1 inhibition was identified, with the trans-inhibition potency being greater than that of cis-inhibition. The concept of trans-inhibition may allow us to further understand the mechanism of transporter-mediated DDIs not only for OATP1B1 but also for other transporters and to improve the accuracy and confidence of DDI predictions.

Efficacy and Safety of Fenofibrate-Statin Combination Therapy in Patients With Inadequately Controlled Triglyceride Levels Despite Previous Statin Monotherapy: A Multicenter, Randomized, Double-blind, Phase IV Study

PURPOSE

Residual cardiovascular risk reduction by fenofibrate in patients with high serum triglyceride (TG) levels despite previous statin monotherapy is not well characterized. The purpose of this study was to evaluate the efficacy and safety of a combination of choline fenofibrate and statin in patients with inadequately controlled TG levels despite previous statin monotherapy.

METHODS

This prospective, multicenter, randomized, double-blind study was conducted in Korea. A total of 133 patients with controlled LDL-C but elevated TG levels, already receiving statin monotherapy, were enrolled in the study, which was conducted from July 2018 to December 2019. Patients were randomly assigned to receive combination therapy with choline fenofibrate and statin or statin monotherapy in a 1:1 ratio. After 8 weeks of treatment, the lipid profiles and safety parameters of the patients in the 2 groups were compared.

FINDINGS

The study included 127 patients (64 in the combination group and 63 in the control group) older than 19 years. After 8 weeks of therapy, mean serum TG levels significantly decreased from 269.8 to 145.5 mg/dL (P < 0.0001) in the combination therapy group, whereas no significant changes occurred in the statin monotherapy group (from 271.1 to 280.5 mg/dL). Contrarily, the mean serum HDLC levels significantly increased from 45.0 to 50.4 mg/dL (P = 0.0004) in the combination therapy group, whereas there were no significant changes in the monotherapy group (from 44.3 to 44.7 mg/dL). There were no additional serious adverse events in the combination therapy group compared with the statin monotherapy group.

IMPLICATIONS

The combination therapy using choline fenofibrate and statin was found to be effective in serum TG control and likely tolerable in patients with high TG levels despite statin monotherapy. A larger study, conducted for a longer duration, is needed to evaluate the effectiveness of this combination in reducing cardiovascular risk. ClinicalTrials.gov identifier: NCT03874260.

Screening for Small Molecule Inhibitors of Statin-Induced APP C-terminal Toxic Fragment Production

Alzheimer's disease (AD) is characterized by neuronal and synaptic loss. One process that could contribute to this loss is the intracellular caspase cleavage of the amyloid precursor protein (APP) resulting in release of the toxic C-terminal 31-amino acid peptide APP-C31 along with the production of APPΔC31, full-length APP minus the C-terminal 31 amino acids. We previously found that a mutation in APP that prevents this caspase cleavage ameliorated synaptic loss and cognitive impairment in a murine AD model. Thus, inhibition of this cleavage is a reasonable target for new therapeutic development. In order to identify small molecules that inhibit the generation of APP-C31, we first used an APPΔC31 cleavage site-specific antibody to develop an AlphaLISA to screen several chemical compound libraries for the level of N-terminal fragment production. This antibody was also used to develop an ELISA for validation studies. In both high throughput screening (HTS) and validation testing, the ability of compounds to inhibit simvastatin- (HTS) or cerivastatin- (validation studies) induced caspase cleavage at the APP-D720 cleavage site was determined in Chinese hamster ovary (CHO) cells stably transfected with wildtype (wt) human APP (CHO-7W). Several compounds, as well as control pan-caspase inhibitor Q-VD-OPh, inhibited APPΔC31 production (measured fragment) and rescued cell death in a dose-dependent manner. The effective compounds fell into several classes including SERCA inhibitors, inhibitors of Wnt signaling, and calcium channel antagonists. Further studies are underway to evaluate the efficacy of lead compounds - identified here using cells and tissues expressing wt human APP - in mouse models of AD expressing mutated human APP, as well as to identify additional compounds and determine the mechanisms by which they exert their effects.

Quantitative Analyses of Hepatic OATP-Mediated Interactions Between Statins and Inhibitors Using PBPK Modeling With a Parameter Optimization Method

This study aimed to construct a widely applicable method for quantitative analyses of drug-drug interactions (DDIs) caused by the inhibition of hepatic organic anion transporting polypeptides (OATPs) using physiologically based pharmacokinetic (PBPK) modeling. Models were constructed for pitavastatin, fluvastatin, and pravastatin as substrates and cyclosporin A (CsA) and rifampicin (RIF) as inhibitors, where enterohepatic circulations (EHC) of statins were incorporated. By fitting to clinical data, parameters that described absorption, hepatic elimination, and EHC processes were optimized, and the extent of these DDIs was explained satisfactorily. Similar in vivo inhibition constant (K_i ) values of each inhibitor against OATPs were obtained, regardless of the substrates. Estimated K_i values of CsA were comparable to reported in vitro values with the preincubation of CsA, while those of RIF were smaller than reported in vitro values (coincubation). In conclusion, this study proposes a method to optimize in vivo PBPK parameters in hepatic uptake transporter-mediated DDIs.

Case report of exercise and statin-fibrate combination therapy-caused myopathy in a patient with metabolic syndrome: contradictions between the two main therapeutic pathways

Background

Lifestyle modifications including exercise are beneficial and fundamentally part of the therapy of metabolic syndrome, although in most of the cases medical interventions are also required to reach the target values in the laboratory parameters. Statin and fibrate combination therapy is considered to be safe and effective in dyslipidaemia and metabolic syndrome. However, increased physical activity can enhance the statin and fibrate-associated myopathy. Myositis and the rare but life-threatening rhabdomyolysis are causing a conflict between exercise and statin-fibrate therapy, which is yet to be resolved.

Case presentation

We present a case of a 43-year-old Caucasian man with metabolic syndrome who had the side-effect of exercise and drug-associated myositis. The patient had only transient moderate complaints and rhabdomyolysis could be avoided with the one-month creatine kinase control, a test which is not recommended routinely by the new guidelines.

Conclusions

We would like to turn the spotlight on the possible complications of statin-fibrate therapy and exercise, when strict follow-up is recommended. In this condition high number of patients can be affected and the responsibility of general practitioners is accentuated.

Uptake transporters of the human OATP family: molecular characteristics, substrates, their role in drug-drug interactions, and functional consequences of polymorphisms

Organic anion transporting polypeptides (OATPs, gene family: SLC21/SLCO) mediate the uptake of a broad range of substrates including several widely prescribed drugs into cells. Drug substrates for members of the human OATP family include HMG-CoA-reductase inhibitors (statins), antibiotics, anticancer agents, and cardiac glycosides. OATPs are expressed in a variety of different tissues including brain, intestine, liver, and kidney, suggesting that these uptake transporters are important for drug absorption, distribution, and excretion. Because of their wide tissue distribution and broad substrate spectrum, altered transport kinetics, for example, due to drug-drug interactions or due to the functional consequences of genetic variations (polymorphisms), can contribute to the interindividual variability of drug effects. Therefore, the molecular characteristics of human OATP family members, the role of human OATPs in drug-drug interactions, and the in vitro analysis of the functional consequences of genetic variations in SLCO genes encoding OATP proteins are the focus of this chapter.

Effects of statins on skeletal muscle: a perspective for physical therapists

Hyperlipidemia, also known as high blood cholesterol, is a cardiovascular health risk that affects more than one third of adults in the United States. Statins are commonly prescribed and successful lipid-lowering medications that reduce the risks associated with cardiovascular disease. The side effects most commonly associated with statin use involve muscle cramping, soreness, fatigue, weakness, and, in rare cases, rapid muscle breakdown that can lead to death. Often, these side effects can become apparent during or after strenuous bouts of exercise. Although the mechanisms by which statins affect muscle performance are not entirely understood, recent research has identified some common causative factors. As musculoskeletal and exercise specialists, physical therapists have a unique opportunity to identify adverse effects related to statin use. The purposes of this perspective article are: (1) to review the metabolism and mechanisms of actions of statins, (2) to discuss the effects of statins on skeletal muscle function, (3) to detail the clinical presentation of statin-induced myopathies, (4) to outline the testing used to diagnose statin-induced myopathies, and (5) to introduce a role for the physical therapist for the screening and detection of suspected statin-induced skeletal muscle myopathy.

In vitro evidence for the role of OATP and OCT uptake transporters in drug-drug interactions

BACKGROUND

Transport proteins, for example the drug export pump P-glycoprotein, are important for the absorption, distribution and excretion of drugs. Inhibition and induction of P-glycoprotein efflux function is a well-established mechanism of drug-drug interactions. Alteration of transporter-mediated drug uptake by concomitantly administered drugs may also result in a change in drug pharmacokinetics. These uptake transporter-mediated drug-drug interactions are the focus of this review.

OBJECTIVE

To examine the current in vitro evidence on interactions mediated by OATPs (organic anion transporting polypeptides) and OCTs (organic cation transporters).

METHODS

Comparing data of in vivo observed drug-drug interactions with in vitro analysed alterations in drug transport mediated by the hepatic expressed uptake transporters OATP1B1, OATP1B3 and OCT1 and by the renal expressed OCT2 protein.

RESULTS/CONCLUSIONS

Some of the previously in vivo described drug-drug interactions could be explained by alteration in uptake transporter function demonstrating that inhibition or induction of uptake transporters is a newly recognised mechanism of potential drug-drug interactions.

A randomized placebo-controlled study on the effect of nifedipine on coronary endothelial function and plaque formation in patients with coronary artery disease: the ENCORE II study

AIMS

Endothelial dysfunction and plaque formation are features of atherosclerosis. Inhibition of L-type calcium channels or HMG-CoA pathway improves endothelial function and reduces plaque size. Thus, we investigated in stable coronary artery disease (CAD) the effects of a calcium antagonist on coronary endothelial function and plaque size.

METHODS AND RESULTS

In 454 patients undergoing PCI, acetylcholine (10(-6) to 10(-4) M) was infused in a coronary segment without significant CAD. Changes in coronary diameter were measured and an intravascular ultrasound examination (IVUS) was performed. On top of statin therapy, patients were randomized in a double-blind fashion to placebo or nifedipine GITS 30-60 mg/day and followed for 18-24 months. Blood pressure was lower on nifedipine than on placebo by 5.8/2.1 mmHg (P < 0.001) as was total and LDL cholesterol (4.8 mg/dL; P = 0.495), while HDL was higher (3.6 mg/dL; P = 0.026). In the most constricting segment, nifedipine reduced vasoconstriction to acetylcholine (14.0% vs. placebo 7.7%; P < 0.0088). The percentage change in plaque volume with nifedipine and placebo, respectively, was 1.0 and 1.9%, ns.

CONCLUSION

The ENCORE II trial demonstrates in a multi-centre setting that calcium channel blockade with nifedipine for up to 2 years improves coronary endothelial function on top of statin treatment, but did not show an effect of nifedipine on plaque volume.

Gemfibrozil and its glucuronide inhibit the hepatic uptake of pravastatin mediated by OATP1B1

When pravastatin (40 mg/day) was co-administered with gemfibrozil (600 mg, b.i.d., 3 days) to man, the AUC of pravastatin increased approximately 2-fold. We have clarified that OATP1B1 is a key determinant of the hepatic uptake of pravastatin in humans. Thus, we hypothesized that gemfibrozil and the main plasma metabolites, a glucuronide (gem-glu) and a carboxylic acid metabolite (gem-M3), might inhibit the hepatic uptake of pravastatin and lead to the elevation of the plasma concentration of pravastatin. Gemfibrozil and gem-glu inhibited the uptake of (14)C-pravastatin by human hepatocytes with K(i) values of 31.7 microM and 15.7 microM, respectively and also inhibited pravastatin uptake by OATP1B1-expressing Xenopus laevis oocytes with K(i) values of 15.1 microM and 7.6 microM. Additionally, we examined the biliary transport of pravastatin and demonstrated that pravastatin was transported by MRP2 using both human canalicular membrane vesicles (hCMVs) and human MRP2-expressing vesicles. However, gemfibrozil, gem-glu and gem-M3 did not affect the biliary transport of pravastatin by MRP2. Considering the plasma concentrations of gemfibrozil and gem-glu in humans, the inhibition of OATP1B1-mediated hepatic uptake of pravastatin by gem-glu would contribute, at least in part, to the elevation of plasma concentration of pravastatin by the concomitant use of gemfibrozil.

Inhibition of human organic anion transporter 3 mediated pravastatin transport by gemfibrozil and the metabolites in humans

Coadministration of gemfibrozil (600 mg, b.i.d., 3 days) with pravastatin (40 mg/day) decreased the renal clearance of pravastatin by approximately 40% in healthy volunteers. To investigate the mechanism of this drug-drug interaction in the renal excretion process, we undertook an uptake study of pravastatin using human organic anion transporters (hOATs)-expressing S2 cells. hOAT3 and hOAT4 transported pravastatin in a saturatable manner with Michaelis--Menten constants of 27.7 microM and 257 microM respectively. On the other hand, hOAT1 and hOAT2 did not transport pravastatin. Gemfibrozil and its glucuronide and carboxylic metabolite forms inhibited the uptake of pravastatin by hOAT3 with IC(50) values of 6.8 microM, 19.7 microM and 5.4 microM, respectively. Considering the plasma concentrations of gemfibrozil and its metabolites in humans, the inhibition of hOAT3-mediated pravastatin transport by gemfibrozil and its metabolites would lead to a decrease in the renal clearance of pravastatin in clinical settings.

FLOW CYTOMETRIC EVALUATION OF SYNERGISTIC PRO-APOPTOTIC EFFECTS OF STATINS AND CLOFIBRATES IN IM-9 HUMAN LYMPHOBLASTS

1. In the present study, we evaluated fibrate-mediated potentiation of statin-induced apoptosis in IM-9 human lymphoblasts. 2. The pro-apoptotic effects of statin and fibrate were measured by flow cytometry with biotin-annexin V, followed by addition of avidin-fluorescein isothiocyanate and propidium iodide. Apoptosis was confirmed using karyopyknotic staining, as well as detection of DNA fragmentation and caspase 3 activation. 3. Incubation of IM-9 cells with both 0.1 micromol/L cerivastatin and 200 micromol/L clofibrate had a synergistic effect compared with 0.1 micromol/L cerivastatin alone or 200 micromol/L clofibrate alone. The magnitude of apoptosis induced by various combinations of statins and clofibrate were as follows: cerivastatin (0.1 micromol/L) + clofibrate (200 micromol/L) > atorvastatin (0.1 micromol/L) + clofibrate (200 micromol/L) > pravastatin (100 micromol/L) + clofibrate (200 micromol/L). Other fibrates (bezafibrate and clinofibrate) did not show any synergistic effect. Furthermore, karyopyknotic staining, caspase 3 activation and DNA fragmentation demonstrated synergistic pro-apoptotic effects of statin and fibrate. 4. The results of the present study suggest that simultaneous treatment with statins and clofibrate could provide improved therapeutic efficacy in leukaemia patients.

Pharmacogenetics and pharmacogenomics of cholesterol-lowering therapy

PURPOSE OF REVIEW

To summarize recent findings on pharmacokinetics, pharmacodynamics, drug-drug interactions and influence of lifestyle heterogeneity on adverse events in cholesterol-lowering therapy

RECENT FINDINGS

The prevention of cardiovascular disease is critically dependent on lipid-lowery therapy, including statins, cholesterol absorption inhibitors, fibrates and nicotinic acid. Statins are the most prescribed drugs in lipid lowering therapy with variability in response and almost one third of the patients do not meet their treatment goals. The severe adverse effects of treatment with cerivastatin stimulated the search for new genes and gene variations affecting pharmacokinetics, drug-drug interactions and pharmacodynamics. Moreover, instead of monotherapy, combined therapy of statins with ezetemibe and niacin was considered. This led to the identification of CD13, NPC1L1 and HM74A as new targets and CYP2C8 and glucuronidation enzymes as potential targets for drug-drug interactions. Moreover multiple polymorphic sites and pleiotrophic gene targets were reinvestigated in larger cohorts and the relevant pathogenetic factors start to evolve.

SUMMARY

Statin therapy is widely used and well tolerated by the majority of patients. To further reduce potential adverse effects and to increase efficacy, combined therapy concepts with ezetimibe or niacin are underway.

Evaluation of apoptosis and necrosis induced by statins using fluorescence-enhanced flow cytometry

The purpose of this study was to evaluate the apoptosis and necrosis induced by five kinds of statins in IM-9 human lymphoblasts with fluorescence-enhanced flow cytometry using avidin-biotin complex. IM-9 human lymphoblasts (2 x 10(4) cells/cm2) were seeded into tissue culture plates and incubated with five kinds of statins. Statin-treated cells were first incubated with biotin-annexin V, followed by addition of avidin-FITC and propidium iodide, and then subjected to flow cytometry. The fluorescence intensity was enhanced using an avidin-biotin complex system, resulting in successful separate determination of the statin-induced apoptosis and necrosis by flow cytometry, which enabled us to quantitatively evaluate the statin-induced cell damage. Flow cytometric analysis results in the intensity of statin-induced apoptosis in IM-9 cells as follows: atorvastatin cerivastatin>fluvastatin simvastatin>pravastatin. The intensity of statin-induced necrosis in IM-9 cells was expressed as follows: atorvastatin cerivastatin>fluvastatin simvastatin>pravastatin. The total damage of IM-9 cells induced by five kinds of statins were expressed as the sum of both percentages of apoptosis and necrosis as follows: atorvastatin cerivastatin>fluvastatin simvastatin>pravastatin. Our studies show that fluorescence enhancement with avidin-biotin complex is useful for the identification and quantitation of annexin-positive apoptosis cells and thus, the fluorescence-enhanced flow cytometry was shown to be applicable for screening of statins as new anti-leukemia agents.

Evaluation of drug-drug interaction in the hepatobiliary and renal transport of drugs

Recent studies have revealed the import role played by transporters in the renal and hepatobiliary excretion of many drugs. These transporters exhibit a broad substrate specificity with a degree of overlap, suggesting the possibility of transporter-mediated drug-drug interactions with other substrates. This review is an overview of the roles of transporters and the possibility of transporter-mediated drug-drug interactions. Among the large number of transporters, we compare the Ki values of inhibitors for organic anion transporting polypeptides (OATPs) and organic anion transporters (OATs) and their therapeutic unbound concentrations. Among them, cephalosporins and probenecid have the potential to produce clinically relevant OAT-mediated drug-drug interactions, whereas cyclosporin A and rifampicin may trigger OATP-mediated ones. These drugs have been reported to cause drug-drug interactions in vivo with OATs or OATP substrates, suggesting the possibility of transporter-mediated drug-drug interactions. To avoid adverse consequences of such transporter-mediated drug-drug interactions, we need to be more aware of the role played by drug transporters as well as those caused by drug metabolizing enzymes.

Gemfibrozil and its glucuronide inhibit the organic anion transporting polypeptide 2 (OATP2/OATP1B1:SLC21A6)-mediated hepatic uptake and CYP2C8-mediated metabolism of cerivastatin: analysis of the mechanism of the clinically relevant drug-drug interaction between cerivastatin and gemfibrozil

A serious pharmacokinetic interaction between cerivastatin (CER) and gemfibrozil (GEM) has been reported. In the present study, we examined the inhibitory effects of GEM and its metabolites, M3 and gemfibrozil 1-O-beta-glucuronide (GEM-1-O-glu), on the uptake of CER by human organic anion transporting polypeptide 2 (OATP2)-expressing cells and its metabolism in cytochrome P450 expression systems. Uptake studies showed that GEM and GEM-1-O-glu significantly inhibited the OATP2-mediated uptake of CER with IC(50) values of 72 and 24 microM, respectively. They also inhibited the CYP2C8-mediated metabolism of CER with IC(50) values of 28 and 4 microM, respectively, whereas M3 had no effects. GEM and GEM-1-O-glu minimally inhibited the CYP3A4-mediated metabolism of CER. The IC(50) values of GEM and GEM-1-O-glu for the uptake and the metabolism of CER obtained in the present study were lower than their total, and not unbound, plasma concentrations. However, considering the possibly concentrated high unbound concentrations of GEM-1-O-glu in the liver and its relatively larger plasma unbound fraction compared with GEM itself, the glucuronide inhibition of the CYP2C8-mediated metabolism of CER appears to be the main mechanism for the clinically relevant drug-drug interaction. Previously reported clinical drug interaction studies showing that coadministration of GEM with pravastatin or pitavastatin, both of which are known to be cleared from the plasma by the uptake transporters in the liver, only minimally (less than 2-fold) increased the area under the plasma concentration-time curve of these statins, also supported our present conclusion.

Early detection of drug interactions utilizing a computerized drug prescription handling system-focus on cerivastatin-gemfibrozil

OBJECTIVES

Based on the recent cerivastatin experience, we retrospectively evaluated the effect of notifying a drug alert utilizing a computerized drug-handling system.

METHODS

The evaluation was carried out during three periods: period I corresponded to all prescriptions issued during April, 2001 ("baseline period"), before the Spanish Drug Agency issued alerts on the concomitant therapy with cerivastatin and gemfibrozil; period II (June) corresponded to a time in which a first informative note had been released; and period III (July) after the second warning alert was issued.

RESULTS

Data collected included the reading of 2,693,656 drug prescriptions, 1,937,083 (71.9%) of which contained patient information. Forty-four patients received combined therapy with cerivastatin and gemfibrozil over the three periods, yielding 55 exposures: 27 during the baseline period, and 28 between periods II and III, when the alert bulletins had already been released. Moreover, 41.6% of doctors included in the follow-up repeated the hazardous prescription during those two periods.

CONCLUSIONS

The effect of the informative notes about the risk of prescribing cerivastatin and gemfibrozil concomitantly on doctors' prescribing habits was limited. The system for screening information from drug prescriptions presented herein allows the early detection of drug interactions by identifying the doctors who issue hazardous prescriptions as well as patients at the highest risk of adverse drug reactions, thus allowing a personal feedback with both of them.

Safety considerations for statins

PURPOSE OF REVIEW

The hydroxymethyl glutaryl coenzyme A reductase inhibitors or statins offer important benefits for the large populations of individuals at high risk for coronary heart disease. These drugs have a good safety profile. Nevertheless, differences in physicochemical and pharmacokinetic properties between statins may translate into significant differences in long-term safety. This review focuses on long-term adverse effects related to statin use, namely hepatotoxicity and myopathy. Moreover, the most common drugs used in combination with statins in long-term therapies are analyzed in terms of possible drug/drug interactions affecting the safety of statins.

RECENT FINDINGS

The withdrawal of cerivastatin from the global market in 2001, because of severe cases of rhabdomyolysis, highlighted concerns regarding the safety of the entire class. Afterwards, the role of statins and their interactions with other drugs in precipitating this condition have been carefully reviewed. In approximately 60% of the total number of cases, statin-related rhabdomyolysis was found to be related to drug/drug interactions. Recently, all cases of fatal rhabdomyolysis associated with statin use have been reported to the US Food and Drug Administration. This has shown that fatal rhabdomyolysis among statin users is a rare event, the reporting rates being much less than one death per million prescriptions in the case of all statins except cerivastatin.

SUMMARY

The safety and tolerability of the available statins support their use as the first-line treatment of patients at high risk for coronary heart disease, since the clinical benefits greatly outweigh the small risk of myopathy. Nevertheless, clinicians should be aware of the adverse effects possibly related to statin therapy, particularly in patients at high risk for coronary heart disease and requiring long-term multiple-drug therapies.

Lack of therapeutic interchangeability of HMG-CoA reductase inhibitors

OBJECTIVE

To review relevant literature and provide an opinion on the class effect of hydroxymethylglutaryl coenzyme A reductase inhibitors (statins).

DATA SOURCES

Primary and review articles were identified by MEDLINE search (1990-July 2002).

STUDY SELECTION AND DATA EXTRACTION

Editorials, studies, and review articles related to the class effect or therapeutic interchangeability of statins were reviewed. Also included was information that is relevant to this topic.

DATA SYNTHESIS

Although statins share common main actions, they may have clinically important differences in terms of efficacy and safety. At fixed or allowable dosages, rosuvastatin, atorvastatin, and simvastatin produced greater low-density lipoprotein cholesterol-lowering effects compared with other statins. Some statins have shown reduction in either cardiovascular and/or total mortality. Statins also differ in their structure, pharmacokinetics, potency, and rate of metabolism, any or all of which may have clinical significance. Although inconclusive, subtle differences in nonlipid effects of some statins may have contributed to positive benefits observed in clinical studies. As a result of drug-related deaths, cerivastatin was withdrawn voluntarily from the market, which may raise the question whether there is therapeutic interchangeability (due to class effect) among statins.

CONCLUSIONS

Despite the competition for market share and strategies attempting to identify differences in therapeutic value, few head-to-head comparisons between statins have been performed. The limited, available data suggest that statins are not therapeutically interchangeable.

Rhabdomyolysis associated with cerivastatin: six cases within 3 months at one hospital

Rhabdomyolysis is an uncommon complication associated with 3-hydroxy-3-methylglutaryl coenzyme A reductase inhibitors. We observed six cases of cerivastatin-associated rhabdomyolysis: two patients developed acute renal failure requiring hemodialysis, and one patient died. Four of the patients had impaired renal function, and five were prescribed drugs with the potential to interact with cerivastatin. Also, five of the six patients presented with symptoms of rhabdomyolysis 3-4 weeks after starting cerivastatin therapy.

3-Hydroxy-3-methylglutaryl coenzyme A reductase inhibitors and rhabdomyolysis: considerations in the renal failure patient

An intense debate has developed as to the risk-benefit ratio of 3-hydroxy-3-methylglutaryl coenzyme A reductase inhibitors (statins) following the withdrawal of cerivastatin. The development of rhabdomyolysis in cerivastatin-treated patients should have surprised few since myotoxicity is an accepted class effect of statins. What has sprung from the cerivastatin experience though is a concern for other members of this class. Such misgivings, although understandable, are ill advised. Without question, differences exist in the risk of rhabdomyolysis occurrence amongst the various statins. In this regard, pravastatin and fluvastatin are least likely to produce rhabdomyolysis, which, in part, relates to the fact they are not metabolized by the cytochrome P450 3A4 pathway. When muscle damage occurs with statins it is most often the result of a drug-drug interaction rather than a specific adverse response to statin monotherapy. Such drug-drug interactions increase plasma concentrations of a statin and thereby increase the risk of myotoxicity. A growing consensus exists which supports an expanded use of statins in a range of patient groups including the renal failure patient. Polypharmacy and altered drug metabolism increase the risk of myotoxicity, albeit to an ill-defined degree, in this population. Many factors should enter into the choice of a statin in the multiply medicated renal failure patient.

Rhabdomyolysis and statin therapy: relevance to the elderly

A recent debate has emerged as to the risk-benefit ratio of 3-hydroxy-3-methylglutaryl coenzyme A (HMG-CoA) reductase inhibitors (statins). This debate has centered on the withdrawal of the HMG-CoA reductase inhibitor cerivastatin (Baycol). Its withdrawal was prompted by an unacceptably high rate of rhabdomyolysis associated with its use. The development of rhabdomyolysis in cerivastatin-treated patients surprised few, since myotoxicity is a class effect with HMG-CoA reductase inhibitors. What has sprung from the cerivastatin experience, though, is the concept of "guilt by association"; thus, other members of this class are now viewed in a similarly negative light. Such misgivings are understandable, but to a degree may be ill-advised, since differences exist in the risk and therefore the rate of rhabdomyolysis occurrence among the various HMG-CoA reductase inhibitors. In this regard, pravastatin and fluvastatin are least likely to provoke muscle cell damage, which, at least in part, relates to their not being metabolized by the cytochrome P-450 (CYP) 3A4 pathway. When muscle damage does occur with HMG-CoA reductase inhibitors, it is commonly the result of drug-drug interactions rather than a specific adverse response to HMG-CoA reductase inhibitor monotherapy. Such drug-drug interactions inevitably result in higher plasma concentrations of an HMG-CoA reductase inhibitor and thereby an increased risk of myotoxicity. A growing consensus supports an expanded use of HMG-CoA reductase inhibitors in elderly patients. Polypharmacy and altered drug metabolism both put the elderly patient at increased risk of myotoxicity when drugs in the HMG-CoA reductase inhibitor class are administered. Physicians must take many factors into account when selecting a member of the HMG-CoA reductase inhibitor class, particularly as relates to their use in the multiply medicated elderly patient.