This invention relates to compounds of the formula (I): ##STR00001## or a pharmaceutically acceptable salt thereof, wherein: A, R.sup.1, R.sup.2, R.sup.3, R.sup.4 and R.sup.5 are each as described herein or a pharmaceutically acceptable salt, and compositions containing such compounds and the use of such compounds in the treatment of a condition mediated by 5-HT.sub.4 agonistic activity such as, but not limited to, as gastroesophageal reflux disease, gastrointestinal disease, gastric motility disorder, non-ulcer dyspepsia, functional dyspepsia, irritable bowel syndrome (IBS), constipation, dyspepsia, esophagitis, gastroesophageal disease, nausea, central nervous system disease, Alzheimer's disease, cognitive disorder, emesis, migraine, neurological disease, pain, cardiovascular disorders, cardiac failure, heart arrhythmia, diabetes or apnea syndrome.