Statin induced myopathy: Difference between revisions

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===Vitamin D===
===Vitamin D===
Several studies have evaluated the role of [[vitamin D]] in [[statin induced myopathy]]. The results have shown so far no significant relation between the [[vitamin D]] level and [[statin induced myopathy]]. Hence, it is not recommended to take vitamin D as part of a treatment for [[statin induced myopathy]].
Several studies have evaluated the role of [[vitamin D]] in [[statin induced myopathy]]. The results have shown so far no significant relation between the [[vitamin D]] level and [[statin induced myopathy]]; however, the results of other studies are still pending. Hence, it is not recommended yet to take vitamin D as part of a treatment for [[statin induced myopathy]].
Nevertheless, it is important to check for the vitamin D level as [[vitamin D deficiency]] is common and it can cause symptoms of [[myalgia]] independently from [[statin]] use.<ref name="pmid21547103">{{cite journal| author=Linde R, Peng L, Desai M, Feldman D| title=The role of vitamin D and SLCO1B1*5 gene polymorphism in statin-associated myalgias. | journal=Dermatoendocrinol | year= 2010 | volume= 2 | issue= 2 | pages= 77-84 | pmid=21547103 | doi=10.4161/derm.2.2.13509 | pmc=PMC3081682 | url=http://www.ncbi.nlm.nih.gov/entrez/eutils/elink.fcgi?dbfrom=pubmed&tool=sumsearch.org/cite&retmode=ref&cmd=prlinks&id=21547103  }} </ref><ref name="pmid12723644">{{cite journal| author=Calvo MS, Whiting SJ| title=Prevalence of vitamin D insufficiency in Canada and the United States: importance to health status and efficacy of current food fortification and dietary supplement use. | journal=Nutr Rev | year= 2003 | volume= 61 | issue= 3 | pages= 107-13 | pmid=12723644 | doi= | pmc= | url=http://www.ncbi.nlm.nih.gov/entrez/eutils/elink.fcgi?dbfrom=pubmed&tool=sumsearch.org/cite&retmode=ref&cmd=prlinks&id=12723644  }} </ref>
Nevertheless, it is important to check for the vitamin D level as [[vitamin D deficiency]] is common and it can cause symptoms of [[myalgia]] independently from [[statin]] use.<ref name="pmid21547103">{{cite journal| author=Linde R, Peng L, Desai M, Feldman D| title=The role of vitamin D and SLCO1B1*5 gene polymorphism in statin-associated myalgias. | journal=Dermatoendocrinol | year= 2010 | volume= 2 | issue= 2 | pages= 77-84 | pmid=21547103 | doi=10.4161/derm.2.2.13509 | pmc=PMC3081682 | url=http://www.ncbi.nlm.nih.gov/entrez/eutils/elink.fcgi?dbfrom=pubmed&tool=sumsearch.org/cite&retmode=ref&cmd=prlinks&id=21547103  }} </ref><ref name="pmid12723644">{{cite journal| author=Calvo MS, Whiting SJ| title=Prevalence of vitamin D insufficiency in Canada and the United States: importance to health status and efficacy of current food fortification and dietary supplement use. | journal=Nutr Rev | year= 2003 | volume= 61 | issue= 3 | pages= 107-13 | pmid=12723644 | doi= | pmc= | url=http://www.ncbi.nlm.nih.gov/entrez/eutils/elink.fcgi?dbfrom=pubmed&tool=sumsearch.org/cite&retmode=ref&cmd=prlinks&id=12723644  }} </ref>



Revision as of 15:47, 30 November 2012

Editor-In-Chief: C. Michael Gibson, M.S., M.D. [1]; Associate Editor(s)-in-Chief: Rim Halaby

Overview

Definition

Statin induced myopathy is a spectrum of muscular problems caused by the intake of statins. Myopathy by definition is any pathology of the muscle. The spectrum of statin induced myopathy includes:

Myalgia

  • Myalgia is defined as one or combination of symptoms of muscle weakness, tenderness or pain in the context of normal or minimally elevated creatinine kinase.
  • Patients usually complain of cramping feeling in the muscles.

Asymptomatic Increase in Creatine Kinase

Myositis

  • Myositis is the inflammation of the muscle.
  • Myositis is defined as the presence of symptoms of muscle weakness, tenderness or pain in the setting of an elevated creatine kinase up to ten folds the normal level.

Rhabdomyolysis

Other Statin Induced Myopathies

Pathophysiology

Statin induced myopathy has a complex poorly understood multifactorial pathophysiology. It is postulated that statin induced myopathy is caused by apoptosis of the skeletal muscle cells because of disrupted intracellular calcium signaling and mitochondrial dysfunction due to depletion of mevalonate metabolism products, notably isoprenoids.[4]

The following changes are caused by statin:

  • Changes in cholesterol content and alteration of the membrane fluidity of skeletal muscle cells which disrupts their normal function
  • Changes in skeletal muscle cells membrane electrical properties
  • Changes in Na+/K+ pump density resulting in decreased production of ATP
  • Changes in the excitation-contraction coupling
  • Changes in the cell surface receptor transduction cascades
  • Decreased synthesis of ubiquinone (Q10), a component of the mitochondrial electron transport chain, leading to decreased ATP production and decreased free radical scavenging
  • Increased intracellular calcium causing apoptosis of the skeletal muscle cells[1]
  • Decreased mevalonate metabolism products, particularly isoprenoids, leading to a chain of events that culminate in the apoptosis of skeletal muscle cells[4]

In addition, muscle biopsies of patients suffering from statin induced rhabdomyolysis show a ragged red fibers appearance.[5]

Shown below is an image depicting the mechanism of statin induced myopathy through increasing the intracellular calcium concentration.
Statin induced myopathy through increased intracellular calcium
Statin induced myopathy through increased intracellular calcium

Differential Diagnosis

Prevalence

The prevalence of statin induced myopathy, described as a spectrum of clinical conditions ranging from myalgia to myositis and rhabdomyolysis, is almost 10-15%[7]

Risk Factors

Intrinsic Risk Factors

Extrinsic Risk Factors

Screening

  • The American Heart Association and the National Heart, Lung, and. Blood Institute (AHA/NHLBI) statin clinical advisory panel recommends the measurement of the creatine kinase level before the initiation of statin therapy.
  • The national lipid association does not recommend the measurement of the creatine kinase level before the initiation of statin therapy for all patients. It is useful to check the creatine level in patients with high risk factors for statin induced myopathy as for example patient with kidney diseases.
  • Otherwise, the level of creatine kinase should be measured only in the presence of symptoms of muscle pain, tenderness or pain[7]

History and Symptoms

The symptoms of statin induced myopathy belong to a spectrum ranging from being mild and asymptomatic to severe and lethal. The time of onset of symptoms varies among people, but the median of onset of symptoms is four weeks since the beginning of the treatment. Similarly, the time for the resolution of symptoms after appropriate management also varies among individuals.[11]

The patients usually complain of muscle pain or weakness that:

  • Is located in large, symmetric, proximal muscle groups
  • Gets exacerbated by exercise
  • Gets better within 2 weeks of withholding statin
  • Recurs within 2 weeks of restarting statin[6]

List of Symptoms

In alphabetical order

Diagnosis

Initial Evaluation

A proper evaluation should be done by checking the following:

Treatment

When symptoms of myopathy or elevation of creatine kinase occur in the setting of a patient taking statin, the majority of patients safely continue the treatment with statin. The decision on whether the patient can discontinue or continue statin depends on two factors:

  1. Severity of the symptoms
  2. Increase in the creatine kinase level

Tolerable Symptoms with Absent or Mild Elevation of Creatine Kinase<5ULN

  • Continue statin[13]
  • Consider lowering the dose of statin, adjust the optimal dose of statin depending on the symptoms of the patient

Tolerable Symptoms with Absent or Mild Elevation of Creatine Kinase>5ULN or with Rhabdomyolysis

  • Discontinue statin
  • Ensure an appropriate management for rhabdomyolysis if present by good hydration and follow up[7]
  • Resume the treatment with statin once the symptoms are resolved. Modify the treatment regimen as follows:
    • Administration of a lower dose statin
    • Alternation in the dosing
    • Twice weekly dosing with longer half lives statins
    • Different type of statin.[7]
  • Monitor creatinine kinase levels.

Intolerable Symptoms

  • Discontinue statin regardless of the level of the creatine kinase.[7]
  • Resume the treatment with statin once the symptoms are resolved. Modify the treatment regimen as follows:
    • Administration of a lower dose statin
    • Alternation in the dosing
    • Twice weekly dosing with longer half lives statins
    • Different type of statin.[7]
  • Monitor creatinine kinase levels.

Recurrence of Symptoms

If the symptoms recur despite appropriate management consider:

Multiple statin therapy at multiple doses
Other lipid lowering drugs[17]
Lifestyle changes including diet and exercise
Shown below is an image summarizing the management plan for statin induced myopathy.[18]
Management of statin induced myopathy
Management of statin induced myopathy

Vitamin D

Several studies have evaluated the role of vitamin D in statin induced myopathy. The results have shown so far no significant relation between the vitamin D level and statin induced myopathy; however, the results of other studies are still pending. Hence, it is not recommended yet to take vitamin D as part of a treatment for statin induced myopathy. Nevertheless, it is important to check for the vitamin D level as vitamin D deficiency is common and it can cause symptoms of myalgia independently from statin use.[19][20]

Coenzyme Q10

References

  1. 1.0 1.1 Baker, S.K. & Tarnopolsky, M.A. (2001). Statin myopathies: pathophysiologic and clinical perspectives. Clin. Invest. Med., 24(5): 258-272.
  2. Thompson PD, Clarkson P, Karas RH (2003). "Statin-associated myopathy". JAMA. 289 (13): 1681–90. doi:10.1001/jama.289.13.1681. PMID 12672737.
  3. Radcliffe KA, Campbell WW (2008). "Statin myopathy". Curr Neurol Neurosci Rep. 8 (1): 66–72. PMID 18367041.
  4. 4.0 4.1 Dirks AJ, Jones KM (2006). "Statin-induced apoptosis and skeletal myopathy". Am J Physiol Cell Physiol. 291 (6): C1208–12. doi:10.1152/ajpcell.00226.2006. PMID 16885396.
  5. Mohaupt MG, Karas RH, Babiychuk EB, et al.: Association between statin-associated myopathy and skeletal muscle damage. CMAJ Can Med Assoc J 2009, 181:E11–E18
  6. 6.0 6.1 6.2 Fernandez G, Spatz ES, Jablecki C, Phillips PS (2011). "Statin myopathy: a common dilemma not reflected in clinical trials". Cleve Clin J Med. 78 (6): 393–403. doi:10.3949/ccjm.78a.10073. PMID 21632911.
  7. 7.00 7.01 7.02 7.03 7.04 7.05 7.06 7.07 7.08 7.09 7.10 7.11 Harper CR, Jacobson TA (2010). "Evidence-based management of statin myopathy". Curr Atheroscler Rep. 12 (5): 322–30. doi:10.1007/s11883-010-0120-9. PMID 20628837.
  8. 8.0 8.1 Venero CV, Thompson PD (2009). "Managing statin myopathy". Endocrinol Metab Clin North Am. 38 (1): 121–36. doi:10.1016/j.ecl.2008.11.002. PMID 19217515.
  9. 9.0 9.1 Toth PP, Harper CR, Jacobson TA: Clinical characterization and molecular mechanisms of statin myopathy. Expert Rev Cardiovasc Ther 2008, 6:955–969
  10. 10.0 10.1 10.2 Hamilton-Craig I (2001). "Statin-associated myopathy". Med J Aust. 175 (9): 486–9. PMID 11758079.
  11. Bruckert E, Hayem G, Dejager S, et al.: Mild to moderate muscular symptoms with high-dosage statin therapy in hyper- lipidemic patients–the PRIMO study [see comment]. Cardiovasc Drugs Ther 2005, 19:403–414.
  12. Toth PP, Harper CR, Jacobson TA: Clinical characterization and molecular mechanisms of statin myopathy. Expert Rev Cardiovasc Ther 2008, 6:955–969.
  13. Blaier O, Lishner M, Elis A (2011). "Managing statin-induced muscle toxicity in a lipid clinic". J Clin Pharm Ther. 36 (3): 336–41. doi:10.1111/j.1365-2710.2011.01254.x. PMID 21414023.
  14. Athyros VG, Tziomalos K, Kakafika AI, et al.: Effectiveness of ezetimibe alone or in combination with twice a week Atorvastatin (10 mg) for statin intolerant high-risk patients. Am J Cardiol 2008, 101:483–485.
  15. Rivers SM, Kane MP, Busch RS, et al.: Colesevelam hydrochloride-ezetimibe combination lipid-lowering therapy in patients with diabetes or metabolic syndrome and a history of statin intolerance. Endocr Pract 2007, 13:11–16.
  16. Backes JM, Venero CV, Gibson CA, et al.: Effectiveness and tolerability of every-other-day rosuvastatin dosing in patients with prior statin intolerance. Ann Pharmacother 2008, 42:34–346.
  17. Lu Z, Kou W, Du B, et al.: Effect of Xuezhikang, an extract from red yeast Chinese rice, on coronary events in a Chinese population with previous myocardial infarction. Am J Cardiol 2008, 101:1689–1693.
  18. Jacobson TA: Toward “pain-free” statin prescribing: clinical algorithm for diagnosis and management of myalgia [see comment]. Mayo Clin Proc 2008, 83:687–700.
  19. Linde R, Peng L, Desai M, Feldman D (2010). "The role of vitamin D and SLCO1B1*5 gene polymorphism in statin-associated myalgias". Dermatoendocrinol. 2 (2): 77–84. doi:10.4161/derm.2.2.13509. PMC 3081682. PMID 21547103.
  20. Calvo MS, Whiting SJ (2003). "Prevalence of vitamin D insufficiency in Canada and the United States: importance to health status and efficacy of current food fortification and dietary supplement use". Nutr Rev. 61 (3): 107–13. PMID 12723644.