Nebulized beta 2-adrenoceptor agonists do not affect plasma selenium or glutathione peroxidase activity in patients...

We investigated whether the beta 2-agonists fenoterol and salbutamol decreased plasma selenium and glutathione peroxidase activity in patients with asthma as this may partially explain the findings of reduced selenium status in asthmatic patients. Nine patients with asthma were studied on 3 occasions and inhaled either fenoterol (5 mg), salbutamol (5 mg) or ipratropium bromide (0.5 mg) administered by nebulization using a randomized, double blind, crossover design. Plasma selenium, glutathione peroxidase activity and potassium were measured prior to drug administration and at 15, 30 and 60 minutes after drug. None of the drugs had any effect on plasma selenium or glutathione peroxidase activity. Ipratropium bromide did not affect plasma potassium. Both beta 2-agonists significantly decreased plasma potassium. The mean (SD) maximum decrease was -0.79 (0-18) mmol/l for fenoterol and -0.26 (0-03) mmol/l for salbutamol (both p < or = 0.01) confirming systemic absorption of the drugs. beta 2-agonists are unlikely to be responsible for the reduced selenium status found in some patients with asthma.