Concomitant administration w/ xanthine derivatives & other β-adrenegics & anticholinergics may increase side effects. Hypokalemia caused by β-agonists can be aggravated w/ concomitant administration of xanthine, glucocorticosteroid & diuretic derivatives. Hypokalemia can increase susceptibility to arrhythmias in patients who have been treated w/ digoxin. Decreased bronchodilation effects can occur w/ co-administration of β-blockers. Inhalation of halogenated hydrocarbon anesth eg, halothane, trichlorethylene & enflurane can increase susceptibility to β-agonists CV effects.