58 Care must be taken when prescribing Exelon transdermal patches: • to patients with sick sinus syndrome or conduction defects (sino-atrial block, atrio-ventricular block) (see section 4.8) • to patients with active gastric or duodenal ulcers or patients predisposed to these conditions because rivastigmine may cause increased gastric secretions (see section 4.8) • to patients predisposed to urinary obstruction and seizures because cholinomimetics may induce or exacerbate these diseases. • to patients with a history of asthma or obstructive pulmonary disease.