Avoid administration of tiotropium bromide inhalation powder with other anticholinergic-containing drugs. ( 7.2 ) 7.1 Sympathomimetics, Methylxanthines, Steroids Tiotropium bromide inhalation powder has been used concomitantly with short-acting and long-acting sympathomimetic (beta-agonists) bronchodilators, methylxanthines, and oral and inhaled steroids without increases in adverse reactions. Therefore, avoid coadministration of tiotropium bromide inhalation powder with other anticholinergic-containing drugs as this may lead to an increase in anticholinergic adverse effects [see Warnings and Precautions ( 5.4 , 5.5 ) and Adverse Reactions ( 6 )].
Source: FDA drug label - tiotropium bromide