Do not concomitantly administer w/ other methylxanthines including beverages & foods containing caffeine. Increased t
½ & decreased clearance w/ cimetidine, allopurinol, propranolol, erythromycin, troleandomycin, lincomycin, ciprofloxacin & anti-flu vaccine. Decreased t
½ & increased clearance by phenytoin, anticonvulsants & smoking. Synergistic toxicity w/ ephedrine & other sympathomimetics. May potentiate hypokalemia caused by hypoxia or associated w/ β
2-adrenoceptor stimulants (β
2-agonist), corticosteroids & diuretics.