DRUG-INDUCED MYOPATHY

SUMMARY

1. Statins, gemfibrozil and chronic corticosteroid use are the most common causes. Others: ethanol, cocaine, and heroin.

2. Drug-induced myopathy: patients have severe muscle pain, proximal myopathy and rhabdomyolysis.

3. Glucocorticoid myopathy: chronic myopathy (proximal myopathy & normal CK, EMG) vs. acute quadruplegic myopathy (severe generalised weakness, elevated CK, myoglobinuria, abnormal EMG).

4. If the myopathy is severe (weakness, CK > 3x normal, or myoglobinuria), stop the drugs.

5. Usually, the patients improve when the drug is stopped.

Reference(s)

Wilkinson, I., Furmedge, D. and Sinharay, R. (2017). Oxford handbook of clinical medicine. Oxford: Oxford University Press. Get it on Amazon.
Feather, A., Randall, D. and Waterhouse, M. (2020). Kumar And Clark’s Clinical Medicine. 10th ed. S.L.: Elsevier Health Sciences. Get it on Amazon.
Hannaman, R. A., Bullock, L., Hatchell, C. A., & Yoffe, M. (2016). Internal medicine review core curriculum, 2017-2018. CO Springs, CO: MedStudy.
Therapeutic Guidelines. Melbourne: Therapeutic Guidelines Limited. https://www.tg.org.au [Accessed 2021].