Statin induced myopathy history and symptoms

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

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.^[1]The history of the patient provides a description about the characteristic of the muscle pain as well as details about medications, history of trauma, exercise or excessive alcohol use.

• 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 statins
  • recurs within 2 weeks of restarting statins^[2]

• It is important that the history of the patient includes the list of current medications, mainly any of the following:
  • CYP450 inhibitors: examples of CYP450 inhibitors are azole antifungals (itraconazole, ketoconazole, fluconazole), macrolide antibiotics (erythromycin, clarithromycin), protease inhibitors ( ritonavir, nelfinavir, indinavir).
  • Fibrates: the combination of statins with fibrates is beneficial in the case of metabolic syndrome or diabetic dyslipidemia; however, fibrates increases the risk of statin induced myopathy.^[3]
• The patient should be asked about any history of excessive exercise or trauma.^[3]

In alphabetical order

• Fatigue
• Generalized aching
• Low back or proximal muscle pain
• Myalgia
• Nocturnal muscle cramps
• Tendon pain
• Weakness^[4]