Hyperkalemic periodic paralysis (HyperPP) is a rare neurological channelopathy caused by gain-of-function mutations in the skeletal muscle sodium channel gene (SCN4A) that disrupts sarcolemmal membrane excitability. Clinically, HyperPP is characterised by episodic muscle weakness attacks with associated rise in serum potassium and a degree of myotonia. Attacks are triggered by exercise, stress, potassium-rich food and a fasting state.
Therapy of periodic paralysis typically consists of avoiding triggers and the use of prophylactic carbonic anhydrase inhibitors. Although these drugs have shown their efficacy in randomised controlled trials (RCTs), many patients oppose a daily drug intake and side effects are frequently experienced.1
Alternatively, salbutamol has been used as an attack treatment in HyperPP, presumably because catecholamines stimulate the cellular uptake of potassium.2 Still, only a few patients with HyperPP are being treated with salbutamol and the large heterogeneity in individual treatment responses makes it difficult to predict who will…