Medical providers are alerted to the following areas of risk when treating other conditions in McArdle patients. Care should also be taken when referring patients for physical therapy (page 14).

Statin therapy

• Although statin medications are generally well-tolerated, the most common side effects relate to skeletal muscle (myalgia, myositis, rhabdomyolysis) [1].

• People with McArdle’s may be at increased risk of muscle side effects from statins.

• If a patient needs a statin, establish their baseline CK level (page 10) before initiating treatment.

• Monitor symptoms and plasma CK weekly for the first few weeks, then extend the interval in stages to normal practice.

• Other cholesterol lowering drugs may also worsen myopathy in McArdle patients [2].

[1] Genetic risk factors associated with lipid-lowering drug induced myopathies. Vladutiu, G.D. et al. (2006) Musc Nv 34: 153-162.

[2] Worsening myopathy associate with ezetimibe in a patient with McArdle Disease. (2005) Perez-Calvo J, Civeira-Murillo F, Cabello A. QJM;98:461e4.

Drug side effects

• When prescribing for other medical conditions always check for any side effect of rhabdomyolysis (for example succinylcholine).

• For a list derived from the British National Formulary [1] see table 12.1, page 145, The McArdle Disease Handbook (page 19), free via our website.

[1] British National Formulary. Joint Formulary Committee London: British Medical Association and Royal Pharmaceutical Society.