Closely monitor patients w/ bronchial asthma during therapy. Patients w/ history of ulcers. Perform appropriate measures (eg, drainage & aspiration) if unable to expectorate. Terminate use if cutaneous & mucosal changes newly occur. Avoid treatment for longer periods in patients w/ histamine intolerance. Pregnancy & lactation.
May cause dangerous secretory congestion due to reduced cough reflex w/ antitussives. Do not mix w/ antibiotics & administer at an interval of at least 2 hr. May potentiate vasodilatory effects of nitroglycerin. Reduced effectiveness w/ activated carbon in high doses. May affect colorimetric determination of salicylates & determination results of ketone bodies.