Pharmacological and nutritional treatment for McArdle disease

McArdle Disease (also known as glycogen storage disease type V) is a disorder affecting muscle metabolism and is caused by the absence of an enzyme called muscle phosphorylase. This causes an inability to break down glycogen 'fuel' stores. The condition leads to pain and fatigue with strenuous exercise. Sometimes severe muscle damage may develop and occasionally this results in acute reversible kidney failure. No benefit was found with the following treatments: D-ribose, glucagon, verapamil, vitamin B6, oral branched chain amino acids, dantrolene sodium, high dose creatine and ramipril. Minimal benefit was found with low dose creatine and ramipril for patients who also have the D/D angiotensin converting enzyme (ACE) phenotype.Taking low dose creatine supplements has a minor benefit in improving exercise tolerance in a small number of people with the condition. Taking a sugary drink before planned strenuous exercise can improve performance but this treatment is not practical for day-to-day living. A diet rich in carbohydrate may be superior to a diet rich in protein but this evidence is based upon only a small number of participants.