Myopathy Associated With HMG-CoA Reductase Inhibitors (Statins): A Series of 10 Patients and Review of the Literature

High-dose atorvastatin therapy progressively decreases skeletal muscle mitochondrial respiratory capacity in humans

BACKGROUNDWhile the benefits of statin therapy on atherosclerotic cardiovascular disease are clear, patients often experience mild to moderate skeletal myopathic symptoms, the mechanism for which is unknown. This study investigated the potential effect of high-dose atorvastatin therapy on skeletal muscle mitochondrial function and whole-body aerobic capacity in humans.METHODSEight overweight (BMI, 31.9 ± 2.0) but otherwise healthy sedentary adults (4 females, 4 males) were studied before (day 0) and 14, 28, and 56 days after initiating atorvastatin (80 mg/d) therapy.RESULTSMaximal ADP-stimulated respiration, measured in permeabilized fiber bundles from muscle biopsies taken at each time point, declined gradually over the course of atorvastatin treatment, resulting in > 30% loss of skeletal muscle mitochondrial oxidative phosphorylation capacity by day 56. Indices of in vivo muscle oxidative capacity (via near-infrared spectroscopy) decreased by 23% to 45%. In whole muscle homogenates from day 0 biopsies, atorvastatin inhibited complex III activity at midmicromolar concentrations, whereas complex IV activity was inhibited at low nanomolar concentrations.CONCLUSIONThese findings demonstrate that high-dose atorvastatin treatment elicits a striking progressive decline in skeletal muscle mitochondrial respiratory capacity, highlighting the need for longer-term dose-response studies in different patient populations to thoroughly define the effect of statin therapy on skeletal muscle health.FUNDINGNIH R01 AR071263.

Amiodarone-Induced Multi-Systemic Toxicity Involving the Liver, Lungs, Thyroid, and Eyes: A Case Report

Objectives

Amiodarone is widely used to treat arrhythmia. However, amiodarone is known for its severe toxicity to the liver, lungs, and thyroid. Amiodarone causes liver damage ranging from asymptomatic serum aminotransferase elevation to hepatic failure requiring liver transplantation. Although amiodarone toxicity has been reported, its simultaneous multi-organ toxicity is not well-known. Here, we introduce a novel case of multi-systemic amiodarone toxicity involving the liver, lungs, thyroid, and eyes.

Case Presentation

A 61-year-old woman visited the emergency room due to general weakness, nausea, visual disturbance, heat intolerance, and a non-productive cough. The patient had been using clopidogrel and amiodarone due to underlying atrial fibrillation. The total level of bilirubin was 0.71 mg/dL, aspartate aminotransferase was 358 U/L, alanine aminotransferase was 177 U/L, and prothrombin time was 27.1 s. Computed tomography showed diffuse increased liver intensity and scattered hyperattenuated nodular consolidations in both lungs. Transthoracic needle lung biopsy revealed fibrinoid interstitial inflammation with atypical change of type II pneumocytes and intra-alveolar foamy macrophages. In addition, the thyroid-stimulating hormone level was <0.008 μIU/mL, and free thyroxine was 4.67 ng/dL. The thyroid scan showed diffuse homogenous intake of technetium-99 m pertechnetate in both thyroid lobes. The ophthalmologic exam detected bilateral symmetrical corneal deposits in a vortex pattern. With these findings, we could diagnose amiodarone-induced hepatic, pulmonary, thyroid, and ophthalmologic toxicity. Liver function was restored after cessation of amiodarone, and thyroid function was normalized with methimazole administration. However, due to aggravated lung consolidations, systemic steroid treatment was administered, and improvement was seen 1 week after, at the follow-up exam. As her symptoms improved, she was discharged with a plan of steroid administration for 3 to 6 months.

Conclusions

This case implies the possibility of multi-systemic amiodarone toxicity. Thus, the toxicity of amiodarone to multiple organs must be monitored. Prompt cessation of the drug should be considered upon diagnosis.

Voriconazole- induced severe hypokalemic rhabdomyolysis: A case report

We report a child who presented with lower limb weakness and inability to walk, laboratory confirmed severe hypokalemia with typical electrocardiogram changes, and evidence of rhabdomyolysis while on voriconazole treatment for Pseudallescheria boydii soft tissue infection. Although voriconazole is a well-tolerated antifungal agent, hypokalemia is a well-known, yet uncommon side effect associated with its use. Furthermore, hypokalemic-rhabdomyolysis has not been reported with voriconazole use alone. Maintaining the clinical suspicion about the potential association between voriconazole and hypokalemic-rhabdomyolysis can lead to prompt recognition and intervention.

The safety of ezetimibe and simvastatin combination for the treatment of hypercholesterolemia

INTRODUCTION

In the light of the most recent and stricter dyslipidemia treatment guidelines, the need for combination hypolipidemic therapy is increasing. Ezetimibe plus simvastatin is available as a fixed dose therapy offering an efficient hypolipidemic treatment choice. Based on the positive results of the IMProved Reduction of Outcomes: Vytorin Efficacy International Trial (IMPROVE-IT) trial, the use of this drug combination is expected to increase in the next years.

AREAS COVERED

This review discusses the current evidence regarding the safety of ezetimibe/simvastatin combination. Current evidence regarding possible associated side effects (musculoskeletal, gastrointestinal, endocrine, hematological, renal, ophthalmologic, allergic, malignancy) and drug interactions of this combination is thoroughly discussed.

EXPERT OPINION

Ezetimibe and simvastatin treatment, either as a single pill or the combined use of the individual compounds, offers limited additional risk compared with simvastatin monotherapy and comprises a safe and efficient choice for dyslipidemia treatment in high-risk and diabetic patients.

Non-traditional dosing of statins in statin-intolerant patients-is it worth a try?

In this manuscript, three manifestations of statin intolerance will be covered. The first, myopathy, is mostly subjective with variable complaints of myalgias often worsened by exercise, muscle cramping or weakness, and at times associated with a biomarker, elevations in creatine kinase (CK). A rare but serious manifestation can be rhabdomyolysis. The second, liver toxicity, is associated with reversible biochemical increases in transaminases and rarely other liver function tests. Finally, statin-related central nervous system (CNS) toxicity typically defined as cognitive impairment is quite rare and appears to be idiosyncratic. Statin dose alternatives will then be discussed and highlighted in the setting of the new cholesterol-lowering guidelines. Non-statin lipid-altering therapies as well as other alternative therapies will also be reviewed.

Outcomes of statin myopathy after statin withdrawal

OBJECTIVE

To study the outcomes of statin myopathy after statin withdrawal.

METHODS

Sixty-nine patients with mild statin myopathy were studied by chart review.

RESULTS

Mean age at presentation was 62.1 years. Forty-nine (71.0%) of the 69 patients were men. Mean duration of follow-up after statin withdrawal was 18.2 months. Muscle symptoms improved in 9 (13.0%) and completely resolved in 50 (72.5%) patients. Thirteen (18.8%)/69 patients had symptoms lingered beyond 14 months. Creatine kinase (CK) levels were elevated in 52 (75.4%)/69 patients at initial presentation and returned to normal in 11 (21.3%)/52 patients at follow-up. Symptom improvement was not influenced by the initial presence of weakness, CK elevation, or myopathic changes on electromyography or muscle biopsy.

CONCLUSIONS

Muscle symptoms can linger beyond 14 months, and it is difficult to predict which patients will have a prolonged recovery course. CK normalization often lags behind symptom improvement, and this should not be the only indication for muscle biopsy.

Prevalence and risk factors of muscle complications secondary to statins

INTRODUCTION

The aim of the study was to investigate the prevalence and risk factors of muscle complications among patients using statins.

METHODS

We conducted a prospective comparative study on 345 patients receiving statins and compared the findings with an age- and gender-matched control group of 85 subjects. Univariate and multivariate analyses with logistic regression models were used to study the association of different patient and disease characteristics with muscle complications.

RESULTS

Adverse reactions were reported by 21% of patients and 5.9% of controls (P = 0.0013). Objective weakness was found in 15% of the patients who reported muscle symptoms (3.2% of the total cohort), but not in controls. Older age, longer duration of statin use, diabetes, stroke, and lower body mass index were associated with increased risk of developing these symptoms.

CONCLUSIONS

Adverse reactions to statins may be more common than previously reported, and they may be affected by specific patient and disease characteristics.

Approach to the patient who is intolerant of statin therapy

Myopathy occurs in approximately 10% of statin-treated patients and is most commonly manifested by myalgias with or without plasma creatine kinase (CK) elevations. Predisposition exists in patients treated with high doses of potent statins and those who are older, female, have a genetic predisposition, and when statins are coadministered with drugs that compete with or inhibit drug metabolism. In symptomatic patients, CK levels may assist in guiding management. If less than five times the upper limit of normal, the existing statin should be titrated to achieve cholesterol goals and the CK repeated when symptoms appear or worsen. In patients with moderate to severe symptoms and any patient with CK elevated to more than 5-fold the upper limit of normal, the statin should be stopped. Once asymptomatic and CK is reduced (if elevated previously), cholesterol goals can be approached by: 1) a different statin (e.g. fluvastatin or pravastatin), starting with a low dose and titrating up; 2) an alternate daily or weekly more potent statin (e.g. rosuvastatin or atorvastatin); or 3) the combination of the lowest tolerated statin with a cholesterol absorption inhibitor (ezetimibe) and/or bile acid sequestrant. Over-the-counter preparations, e.g. red yeast rice, containing natural statin-like agents, or plant sterols can also lower cholesterol. These, however, have limited efficacy to achieve targeted cholesterol levels for most patients. In patients without CK elevations and symptoms, progress can be followed clinically, but in patients who show CK elevations, CK should be monitored. At present, the superiority of one approach has not been demonstrated, and the need for clinical trials in well-characterized patients with statin intolerance cannot be dismissed.

Risk factors for rhabdomyolysis with simvastatin and atorvastatin

OBJECTIVE

To assess the frequency of risk factors for rhabdomyolysis with simvastatin and atorvastatin in cases reported to the Australian Adverse Drug Reactions Advisory Committee (ADRAC).

DESIGN

Reports meeting the definition of rhabdomyolysis were reviewed for risk factors including age > or = 70 years, dose > or = 40 mg, hepatic dysfunction, diabetes mellitus, hyperkalaemia, hypothyroidism and the use of concomitant interacting medications.

RESULTS

Only one report associated with simvastatin and five reports associated with atorvastatin did not list any risk factors for rhabdomyolysis. Interacting medicines featured in 77% of reports of rhabdomyolysis associated with simvastatin and 44% of reports associated with atorvastatin. A comparison of the age profile for reports of atorvastatin- and simvastatin-associated rhabdomyolysis with that for all adverse drug reaction reports received, and for all reports of muscle disorders, suggested a trend towards an increasing risk of rhabdomyolysis with increasing age with simvastatin but not with atorvastatin. Similarly, comparing prescribed tablet strengths from Pharmaceutical Benefits Scheme data with the HMG-CoA reductase inhibitor ('statin') doses in reports of rhabdomyolysis suggested a dose-related risk with simvastatin, but a less increased risk with high-dose atorvastatin.

CONCLUSION

Risk factors for rhabdomyolysis featured in nearly all of the reports of statin-associated rhabdomyolysis and the majority of reports listed multiple risk factors, although dependence on risk factors appeared to be stronger with simvastatin than atorvastatin. The multiplication of risk factors in patients taking simvastatin and atorvastatin should be minimised.

Statin safety: an overview and assessment of the data--2005

The 3-hydroxy-3-methylglutaryl coenzyme A (HMG-CoA) reductase inhibitors, or statin drugs, have been studied in numerous controlled human research trials involving hundreds of thousands of study participants. Statins have been prescribed for millions of patients. Based on this vast research and clinical experience, statins have been shown to improve lipid blood levels and reduce atherosclerotic coronary artery disease (CAD) risk, resulting in reduced CAD morbidity and mortality, and in several studies, reduced overall ("all-cause") mortality. From a safety perspective, both research trial evidence and clinical practice experience have demonstrated that statins are generally well tolerated. However, as with all pharmaceuticals, safety considerations exist with both monotherapy and combination statin therapy, mainly involving potential adverse effects on muscle, liver, kidney, and the nervous system. The evidence supporting statin-related potential adverse experiences on these organ systems is sometimes strong and based on clear clinical trial evidence (such as the increased risk of muscle enzyme elevation with higher statin doses). The evidence is at other times more speculative, being based on case reports and inconclusive clinical trial data (such as possible favorable or unfavorable effects of statins on cognition). Because the use of statins is so widespread, it is useful for the clinician to understand statin safety issues and the level of available evidence supporting the contention that various adverse effects are caused by statins. This review presents an assessment of statin safety based on an overview of the current statin safety data and their clinical implications.

Simvastatin-amiodarone interaction resulting in rhabdomyolysis, azotemia, and possible hepatotoxicity

OBJECTIVE

To describe the fifth reported instance, as of February 15, 2006, of a severe interaction between simvastatin and amiodarone and hypothesize inhibition of CYP3A4 as the major mechanism.

CASE SUMMARY

A 72-year-old white man (178 cm, 77.2 kg) with diabetes mellitus, hyperlipidemia, hypertension, and mild azotemia was hospitalized on September 21, 2004, with thigh weakness, achiness, and dark urine for 7 days. Coronary artery bypass had been performed on July 7, 2004. Amiodarone 200 mg/day was started on July 10, and simvastatin 80 mg/day was initiated on August 13. Laboratory testing on the present admission included creatine kinase (CK) 19,620 U/L (reference range 60-224), blood urea nitrogen 50 mg/dL, creatinine 2.6 mg/dL, aspartate aminotransferase (AST) 912 U/L (30-60), alanine aminotransferase (ALT) 748 U/L (30-60), urine myoglobin 71,100 microg/L (<50), and serum myoglobin 13,877 microg/L (<110). Simvastatin and amiodarone were discontinued, and the patient was hydrated with forced alkaline diuresis. Thirteen days later, his CK was 323 U/L, creatinine 1.7 mg/dL, ALT 145 U/L, and AST 37 U/L.

DISCUSSION

Simvastatin is metabolized primarily by CYP3A4, and amiodarone is a recognized inhibitor of this enzyme. This may, therefore, account for the presumed drug interaction.

CONCLUSIONS

An objective causal assessment suggests that rhabdomyolysis, renal failure, and possibly hepatotoxicity were probably related to an amiodarone-simvastatin interaction.

Muscle Symptoms Associated with Statins: A Series of Twenty Patients

The aim of this study was to examine the clinical profile of statin-induced myalgia in patients with no apparent predisposing factors. Patients who reported muscle complaints that limited daily functioning during statin use were prospectively identified among the patients of Kuusankoski District Hospital and its catchment area, a population of about 100,000, between January 2003 and July 2004. Twenty patients in whom the muscle complaints were probably attributable to the use of a statin were included in this series. There were no cases of severe myopathy or rhabdomyolysis, and the highest creatine kinase value observed was only about 1900 U/l. Of the 18 patients that were evaluable for creatine kinase level, 5 (28%) did not exhibit elevation of creatine kinase and 6 (33%) showed a minor increase only. Following discontinuation of the statin, resolution of symptoms and normalisation of creatine kinase occurred in 11 of the 13 patients with elevated creatine kinase value as well as muscle complaints. Statins may cause clinically important muscle symptoms without inducing a marked creatine kinase elevation.

Rhabdomyolysis in Association with Simvastatin and Amiodarone

OBJECTIVE:

To report a case of severe myopathy associated with concomitant simvastatin and amiodarone therapy.

CASE SUMMARY:

A 63-year-old white man with underlying insulin-dependent diabetes, recent coronary artery bypass surgery, and postoperative hemiplegia was treated with aspirin, metoprolol, furosemide, nitroglycerin, and simvastatin. Due to recurrent atrial fibrillation, oral anticoagulation with phenprocoumon and antiarrhythmic treatment with amiodarone were initiated. Four weeks after starting simvastatin 40 mg/day and 2 weeks after initiating amiodarone 1 g/day for 10 days, then 200 mg/day, he developed diffuse muscle pain with generalized muscular weakness. Laboratory investigations revealed a significant increase of creatine kinase (CK) peaking at 40 392 U/L. Due to a suspected drug interaction of simvastatin with amiodarone, both drugs were stopped. CK normalized over the following 8 days, and the patient made an uneventful recovery. An objective causality assessment revealed that the myopathy was probably related to simvastatin.

DISCUSSION:

Myopathy is a rare but potentially severe adverse reaction associated with statins. Besides high statin doses, concomitant use of fibrates, defined comorbidities, and concurrent use of inhibitors of cytochrome P450 are important additional risk factors. This is especially relevant if statins predominantly metabolized by CYP3A4 are combined with inhibitors of this isoenzyme. Amiodarone is a potent inhibitor of several different CYP isoenzymes, including CYP3A4.

CONCLUSIONS:

Avoiding the concomitant use of drugs with the potential to inhibit CYP-dependent metabolism (eg, amiodarone) or elimination of statins may decrease the risk of statin-associated myopathy. Alternatively, if drug therapy with a potent CYP inhibitor is inevitable, choosing a statin without relevant CYP metabolism (eg, pravastatin) should be considered.